memory: Add TI GPMC driver

The GPMC is a unified memory controller dedicated for interfacing
with external memory devices like
 - Asynchronous SRAM-like memories and ASICs
 - Asynchronous, synchronous, and page mode burst NOR flash
 - NAND flash
 - Pseudo-SRAM devices

This driver will take care of setting up the GPMC based on
the settings specified in the Device tree and then
probe its children.

Signed-off-by: Roger Quadros <rogerq@kernel.org>

5 files changed, 1561 insertions, 0 deletions

diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
index c621f5bba3..56b89f17be 100644
--- a/drivers/memory/Kconfig
+++ b/drivers/memory/Kconfig
@@ -41,4 +41,23 @@ config TI_AEMIF
 	  of 256M bytes of any of these memories can be accessed at a given
 	  time via four chip selects with 64M byte access per chip select.
 
+config TI_GPMC
+	bool "Texas Instruments GPMC driver"
+	depends on ARCH_OMAP2PLUS || ARCH_KEYSTONE || ARCH_K3
+	depends on MEMORY && CLK && OF_CONTROL
+	help
+	  This driver is for the General Purpose Memory Controller (GPMC)
+          present on Texas Instruments SoCs (e.g. OMAP2+). GPMC allows
+          interfacing to a variety of asynchronous as well as synchronous
+          memory drives like NOR, NAND, OneNAND, SRAM.
+
+if TI_GPMC
+config TI_GPMC_DEBUG
+	bool "Debug Texas Instruments GPMC timings"
+	default n
+	help
+	  Enable this to print GPMC timings before and after the GPMC registers
+	  are programmed. This should not be left enabled on production systems.
+endif
+
 endmenu
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
index b27f701865..2b196d78c0 100644
--- a/drivers/memory/Makefile
+++ b/drivers/memory/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_MEMORY) += memory-uclass.o
 obj-$(CONFIG_SANDBOX_MEMORY) += memory-sandbox.o
 obj-$(CONFIG_STM32_FMC2_EBI) += stm32-fmc2-ebi.o
 obj-$(CONFIG_TI_AEMIF) += ti-aemif.o
+obj-$(CONFIG_TI_GPMC) += ti-gpmc.o
diff --git a/drivers/memory/ti-gpmc.c b/drivers/memory/ti-gpmc.c
new file mode 100644
index 0000000000..f511a529b1
--- /dev/null
+++ b/drivers/memory/ti-gpmc.c
@@ -0,0 +1,1240 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Texas Instruments GPMC Driver
+ *
+ * Copyright (C) 2021 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+#include <asm/io.h>
+#include <asm/arch/sys_proto.h>
+#include <clk.h>
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <dm/lists.h>
+#include <linux/mtd/omap_gpmc.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include "ti-gpmc.h"
+
+enum gpmc_clk_domain {
+	GPMC_CD_FCLK,
+	GPMC_CD_CLK
+};
+
+struct gpmc_cs_data {
+	const char *name;
+#define GPMC_CS_RESERVED	BIT(0)
+	u32 flags;
+};
+
+struct ti_gpmc {
+	void __iomem *base;
+	u32 cs_num;
+	u32 nr_waitpins;
+	struct clk *l3_clk;
+	u32 capability_flags;
+	struct resource data;
+};
+
+static struct gpmc_cs_data gpmc_cs[GPMC_CS_NUM];
+static unsigned int gpmc_cs_num = GPMC_CS_NUM;
+static unsigned int gpmc_nr_waitpins;
+static unsigned int gpmc_capability;
+static void __iomem *gpmc_base;
+static struct clk *gpmc_l3_clk;
+
+/* Public, as required by nand/raw/omap_gpmc.c */
+const struct gpmc *gpmc_cfg;
+
+/*
+ * The first 1MB of GPMC address space is typically mapped to
+ * the internal ROM. Never allocate the first page, to
+ * facilitate bug detection; even if we didn't boot from ROM.
+ * As GPMC minimum partition size is 16MB we can only start from
+ * there.
+ */
+#define GPMC_MEM_START		0x1000000
+#define GPMC_MEM_END		0x3FFFFFFF
+
+static void gpmc_write_reg(int idx, u32 val)
+{
+	writel_relaxed(val, gpmc_base + idx);
+}
+
+static u32 gpmc_read_reg(int idx)
+{
+	return readl_relaxed(gpmc_base + idx);
+}
+
+static void gpmc_cs_write_reg(int cs, int idx, u32 val)
+{
+	void __iomem *reg_addr;
+
+	reg_addr = gpmc_base + GPMC_CS0_OFFSET + (cs * GPMC_CS_SIZE) + idx;
+	writel_relaxed(val, reg_addr);
+}
+
+static u32 gpmc_cs_read_reg(int cs, int idx)
+{
+	void __iomem *reg_addr;
+
+	reg_addr = gpmc_base + GPMC_CS0_OFFSET + (cs * GPMC_CS_SIZE) + idx;
+	return readl_relaxed(reg_addr);
+}
+
+static unsigned long gpmc_get_fclk_period(void)
+{
+	unsigned long rate = clk_get_rate(gpmc_l3_clk);
+
+	rate /= 1000;
+	rate = 1000000000 / rate;	/* In picoseconds */
+
+	return rate;
+}
+
+/**
+ * gpmc_get_clk_period - get period of selected clock domain in ps
+ * @cs: Chip Select Region.
+ * @cd: Clock Domain.
+ *
+ * GPMC_CS_CONFIG1 GPMCFCLKDIVIDER for cs has to be setup
+ * prior to calling this function with GPMC_CD_CLK.
+ */
+static unsigned long gpmc_get_clk_period(int cs, enum gpmc_clk_domain cd)
+{
+	unsigned long tick_ps = gpmc_get_fclk_period();
+	u32 l;
+	int div;
+
+	switch (cd) {
+	case GPMC_CD_CLK:
+		/* get current clk divider */
+		l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+		div = (l & 0x03) + 1;
+		/* get GPMC_CLK period */
+		tick_ps *= div;
+		break;
+	case GPMC_CD_FCLK:
+	default:
+		break;
+	}
+
+	return tick_ps;
+}
+
+static unsigned int gpmc_ns_to_clk_ticks(unsigned int time_ns, int cs,
+					 enum gpmc_clk_domain cd)
+{
+	unsigned long tick_ps;
+
+	/* Calculate in picosecs to yield more exact results */
+	tick_ps = gpmc_get_clk_period(cs, cd);
+
+	return (time_ns * 1000 + tick_ps - 1) / tick_ps;
+}
+
+static unsigned int gpmc_ns_to_ticks(unsigned int time_ns)
+{
+	return gpmc_ns_to_clk_ticks(time_ns, /* any CS */ 0, GPMC_CD_FCLK);
+}
+
+static unsigned int gpmc_ps_to_ticks(unsigned int time_ps)
+{
+	unsigned long tick_ps;
+
+	/* Calculate in picosecs to yield more exact results */
+	tick_ps = gpmc_get_fclk_period();
+
+	return (time_ps + tick_ps - 1) / tick_ps;
+}
+
+static __maybe_unused unsigned int gpmc_clk_ticks_to_ns(unsigned int ticks, int cs,
+							enum gpmc_clk_domain cd)
+{
+	return ticks * gpmc_get_clk_period(cs, cd) / 1000;
+}
+
+static inline void gpmc_cs_modify_reg(int cs, int reg, u32 mask, bool value)
+{
+	u32 l;
+
+	l = gpmc_cs_read_reg(cs, reg);
+	if (value)
+		l |= mask;
+	else
+		l &= ~mask;
+	gpmc_cs_write_reg(cs, reg, l);
+}
+
+static void gpmc_cs_bool_timings(int cs, const struct gpmc_bool_timings *p)
+{
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG1,
+			   GPMC_CONFIG1_TIME_PARA_GRAN,
+			   p->time_para_granularity);
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG2,
+			   GPMC_CONFIG2_CSEXTRADELAY, p->cs_extra_delay);
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG3,
+			   GPMC_CONFIG3_ADVEXTRADELAY, p->adv_extra_delay);
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG4,
+			   GPMC_CONFIG4_OEEXTRADELAY, p->oe_extra_delay);
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG4,
+			   GPMC_CONFIG4_WEEXTRADELAY, p->we_extra_delay);
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG6,
+			   GPMC_CONFIG6_CYCLE2CYCLESAMECSEN,
+			   p->cycle2cyclesamecsen);
+	gpmc_cs_modify_reg(cs, GPMC_CS_CONFIG6,
+			   GPMC_CONFIG6_CYCLE2CYCLEDIFFCSEN,
+			   p->cycle2cyclediffcsen);
+}
+
+#if IS_ENABLED(CONFIG_TI_GPMC_DEBUG)
+/**
+ * get_gpmc_timing_reg - read a timing parameter and print DTS settings for it.
+ * @cs:      Chip Select Region
+ * @reg:     GPMC_CS_CONFIGn register offset.
+ * @st_bit:  Start Bit
+ * @end_bit: End Bit. Must be >= @st_bit.
+ * @max:     Maximum parameter value (before optional @shift).
+ *           If 0, maximum is as high as @st_bit and @end_bit allow.
+ * @name:    DTS node name, w/o "gpmc,"
+ * @cd:      Clock Domain of timing parameter.
+ * @shift:   Parameter value left shifts @shift, which is then printed instead of value.
+ * @raw:     Raw Format Option.
+ *           raw format:  gpmc,name = <value>
+ *           tick format: gpmc,name = <value> /&zwj;* x ns -- y ns; x ticks *&zwj;/
+ *           Where x ns -- y ns result in the same tick value.
+ *           When @max is exceeded, "invalid" is printed inside comment.
+ * @noval:   Parameter values equal to 0 are not printed.
+ * @return:  Specified timing parameter (after optional @shift).
+ *
+ */
+static int get_gpmc_timing_reg(/* timing specifiers */
+	int cs, int reg, int st_bit, int end_bit, int max,
+	const char *name, const enum gpmc_clk_domain cd,
+	/* value transform */
+	int shift,
+	/* format specifiers */
+	bool raw, bool noval)
+{
+	u32 l;
+	int nr_bits;
+	int mask;
+	bool invalid;
+
+	l = gpmc_cs_read_reg(cs, reg);
+	nr_bits = end_bit - st_bit + 1;
+	mask = (1 << nr_bits) - 1;
+	l = (l >> st_bit) & mask;
+	if (!max)
+		max = mask;
+	invalid = l > max;
+	if (shift)
+		l = (shift << l);
+	if (noval && l == 0)
+		return 0;
+	if (!raw) {
+		/* DTS tick format for timings in ns */
+		unsigned int time_ns;
+		unsigned int time_ns_min = 0;
+
+		if (l)
+			time_ns_min = gpmc_clk_ticks_to_ns(l - 1, cs, cd) + 1;
+		time_ns = gpmc_clk_ticks_to_ns(l, cs, cd);
+		pr_info("gpmc,%s = <%u>; /* %u ns - %u ns; %i ticks%s*/\n",
+			name, time_ns, time_ns_min, time_ns, l,
+			invalid ? "; invalid " : " ");
+	} else {
+		/* raw format */
+		pr_info("gpmc,%s = <%u>;%s\n", name, l,
+			invalid ? " /* invalid */" : "");
+	}
+
+	return l;
+}
+
+#define GPMC_PRINT_CONFIG(cs, config) \
+	pr_info("CS%i %s: 0x%08x\n", cs, #config, \
+		gpmc_cs_read_reg(cs, config))
+#define GPMC_GET_RAW(reg, st, end, field) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, GPMC_CD_FCLK, 0, 1, 0)
+#define GPMC_GET_RAW_MAX(reg, st, end, max, field) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), (max), field, GPMC_CD_FCLK, 0, 1, 0)
+#define GPMC_GET_RAW_BOOL(reg, st, end, field) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, GPMC_CD_FCLK, 0, 1, 1)
+#define GPMC_GET_RAW_SHIFT_MAX(reg, st, end, shift, max, field) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), (max), field, GPMC_CD_FCLK, (shift), 1, 1)
+#define GPMC_GET_TICKS(reg, st, end, field) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, GPMC_CD_FCLK, 0, 0, 0)
+#define GPMC_GET_TICKS_CD(reg, st, end, field, cd) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), 0, field, (cd), 0, 0, 0)
+#define GPMC_GET_TICKS_CD_MAX(reg, st, end, max, field, cd) \
+	get_gpmc_timing_reg(cs, (reg), (st), (end), (max), field, (cd), 0, 0, 0)
+
+static void gpmc_show_regs(int cs, const char *desc)
+{
+	pr_info("gpmc cs%i %s:\n", cs, desc);
+	GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG1);
+	GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG2);
+	GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG3);
+	GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG4);
+	GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG5);
+	GPMC_PRINT_CONFIG(cs, GPMC_CS_CONFIG6);
+}
+
+/*
+ * Note that gpmc,wait-pin handing wrongly assumes bit 8 is available,
+ * see commit c9fb809.
+ */
+static void gpmc_cs_show_timings(int cs, const char *desc)
+{
+	gpmc_show_regs(cs, desc);
+
+	pr_info("gpmc cs%i access configuration:\n", cs);
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1,  4,  4, "time-para-granularity");
+	GPMC_GET_RAW(GPMC_CS_CONFIG1,  8,  9, "mux-add-data");
+	GPMC_GET_RAW_SHIFT_MAX(GPMC_CS_CONFIG1, 12, 13, 1,
+			       GPMC_CONFIG1_DEVICESIZE_MAX, "device-width");
+	GPMC_GET_RAW(GPMC_CS_CONFIG1, 16, 17, "wait-pin");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 21, 21, "wait-on-write");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 22, 22, "wait-on-read");
+	GPMC_GET_RAW_SHIFT_MAX(GPMC_CS_CONFIG1, 23, 24, 4,
+			       GPMC_CONFIG1_ATTACHEDDEVICEPAGELENGTH_MAX,
+			       "burst-length");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 27, 27, "sync-write");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 28, 28, "burst-write");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 29, 29, "gpmc,sync-read");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 30, 30, "burst-read");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG1, 31, 31, "burst-wrap");
+
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG2,  7,  7, "cs-extra-delay");
+
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG3,  7,  7, "adv-extra-delay");
+
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG4, 23, 23, "we-extra-delay");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG4,  7,  7, "oe-extra-delay");
+
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG6,  7,  7, "cycle2cycle-samecsen");
+	GPMC_GET_RAW_BOOL(GPMC_CS_CONFIG6,  6,  6, "cycle2cycle-diffcsen");
+
+	pr_info("gpmc cs%i timings configuration:\n", cs);
+	GPMC_GET_TICKS(GPMC_CS_CONFIG2,  0,  3, "cs-on-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG2,  8, 12, "cs-rd-off-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG2, 16, 20, "cs-wr-off-ns");
+
+	GPMC_GET_TICKS(GPMC_CS_CONFIG3,  0,  3, "adv-on-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG3,  8, 12, "adv-rd-off-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG3, 16, 20, "adv-wr-off-ns");
+	if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+		GPMC_GET_TICKS(GPMC_CS_CONFIG3, 4, 6, "adv-aad-mux-on-ns");
+		GPMC_GET_TICKS(GPMC_CS_CONFIG3, 24, 26,
+			       "adv-aad-mux-rd-off-ns");
+		GPMC_GET_TICKS(GPMC_CS_CONFIG3, 28, 30,
+			       "adv-aad-mux-wr-off-ns");
+	}
+
+	GPMC_GET_TICKS(GPMC_CS_CONFIG4,  0,  3, "oe-on-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG4,  8, 12, "oe-off-ns");
+	if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+		GPMC_GET_TICKS(GPMC_CS_CONFIG4,  4,  6, "oe-aad-mux-on-ns");
+		GPMC_GET_TICKS(GPMC_CS_CONFIG4, 13, 15, "oe-aad-mux-off-ns");
+	}
+	GPMC_GET_TICKS(GPMC_CS_CONFIG4, 16, 19, "we-on-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG4, 24, 28, "we-off-ns");
+
+	GPMC_GET_TICKS(GPMC_CS_CONFIG5,  0,  4, "rd-cycle-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG5,  8, 12, "wr-cycle-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG5, 16, 20, "access-ns");
+
+	GPMC_GET_TICKS(GPMC_CS_CONFIG5, 24, 27, "page-burst-access-ns");
+
+	GPMC_GET_TICKS(GPMC_CS_CONFIG6, 0, 3, "bus-turnaround-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG6, 8, 11, "cycle2cycle-delay-ns");
+
+	GPMC_GET_TICKS_CD_MAX(GPMC_CS_CONFIG1, 18, 19,
+			      GPMC_CONFIG1_WAITMONITORINGTIME_MAX,
+			      "wait-monitoring-ns", GPMC_CD_CLK);
+	GPMC_GET_TICKS_CD_MAX(GPMC_CS_CONFIG1, 25, 26,
+			      GPMC_CONFIG1_CLKACTIVATIONTIME_MAX,
+			      "clk-activation-ns", GPMC_CD_FCLK);
+
+	GPMC_GET_TICKS(GPMC_CS_CONFIG6, 16, 19, "wr-data-mux-bus-ns");
+	GPMC_GET_TICKS(GPMC_CS_CONFIG6, 24, 28, "wr-access-ns");
+}
+#else
+static inline void gpmc_cs_show_timings(int cs, const char *desc)
+{
+}
+#endif
+
+/**
+ * set_gpmc_timing_reg - set a single timing parameter for Chip Select Region.
+ * Caller is expected to have initialized CONFIG1 GPMCFCLKDIVIDER
+ * prior to calling this function with @cd equal to GPMC_CD_CLK.
+ *
+ * @cs:      Chip Select Region.
+ * @reg:     GPMC_CS_CONFIGn register offset.
+ * @st_bit:  Start Bit
+ * @end_bit: End Bit. Must be >= @st_bit.
+ * @max:     Maximum parameter value.
+ *           If 0, maximum is as high as @st_bit and @end_bit allow.
+ * @time:    Timing parameter in ns.
+ * @cd:      Timing parameter clock domain.
+ * @name:    Timing parameter name.
+ * @return:  0 on success, -1 on error.
+ */
+static int set_gpmc_timing_reg(int cs, int reg, int st_bit, int end_bit, int max,
+			       int time, enum gpmc_clk_domain cd, const char *name)
+{
+	u32 l;
+	int ticks, mask, nr_bits;
+
+	if (time == 0)
+		ticks = 0;
+	else
+		ticks = gpmc_ns_to_clk_ticks(time, cs, cd);
+	nr_bits = end_bit - st_bit + 1;
+	mask = (1 << nr_bits) - 1;
+
+	if (!max)
+		max = mask;
+
+	if (ticks > max) {
+		pr_err("%s: GPMC CS%d: %s %d ns, %d ticks > %d ticks\n",
+		       __func__, cs, name, time, ticks, max);
+
+		return -1;
+	}
+
+	l = gpmc_cs_read_reg(cs, reg);
+	if (IS_ENABLED(CONFIG_TI_GPMC_DEBUG)) {
+		pr_info("GPMC CS%d: %-17s: %3d ticks, %3lu ns (was %3i ticks) %3d ns\n",
+			cs, name, ticks, gpmc_get_clk_period(cs, cd) * ticks / 1000,
+				(l >> st_bit) & mask, time);
+	}
+
+	l &= ~(mask << st_bit);
+	l |= ticks << st_bit;
+	gpmc_cs_write_reg(cs, reg, l);
+
+	return 0;
+}
+
+/**
+ * gpmc_calc_waitmonitoring_divider - calculate proper GPMCFCLKDIVIDER based on WAITMONITORINGTIME
+ * WAITMONITORINGTIME will be _at least_ as long as desired, i.e.
+ * read  --> don't sample bus too early
+ * write --> data is longer on bus
+ *
+ * Formula:
+ * gpmc_clk_div + 1 = ceil(ceil(waitmonitoringtime_ns / gpmc_fclk_ns)
+ *                    / waitmonitoring_ticks)
+ * WAITMONITORINGTIME resulting in 0 or 1 tick with div = 1 are caught by
+ * div <= 0 check.
+ *
+ * @wait_monitoring: WAITMONITORINGTIME in ns.
+ * @return:          -1 on failure to scale, else proper divider > 0.
+ */
+static int gpmc_calc_waitmonitoring_divider(unsigned int wait_monitoring)
+{
+	int div = gpmc_ns_to_ticks(wait_monitoring);
+
+	div += GPMC_CONFIG1_WAITMONITORINGTIME_MAX - 1;
+	div /= GPMC_CONFIG1_WAITMONITORINGTIME_MAX;
+
+	if (div > 4)
+		return -1;
+	if (div <= 0)
+		div = 1;
+
+	return div;
+}
+
+/**
+ * gpmc_calc_divider - calculate GPMC_FCLK divider for sync_clk GPMC_CLK period.
+ * @sync_clk: GPMC_CLK period in ps.
+ * @return:   Returns at least 1 if GPMC_FCLK can be divided to GPMC_CLK.
+ *            Else, returns -1.
+ */
+static int gpmc_calc_divider(unsigned int sync_clk)
+{
+	int div = gpmc_ps_to_ticks(sync_clk);
+
+	if (div > 4)
+		return -1;
+	if (div <= 0)
+		div = 1;
+
+	return div;
+}
+
+/**
+ * gpmc_cs_set_timings - program timing parameters for Chip Select Region.
+ * @cs:     Chip Select Region.
+ * @t:      GPMC timing parameters.
+ * @s:      GPMC timing settings.
+ * @return: 0 on success, -1 on error.
+ */
+static int gpmc_cs_set_timings(int cs, const struct gpmc_timings *t,
+			       const struct gpmc_settings *s)
+{
+	int div, ret;
+	u32 l;
+
+	div = gpmc_calc_divider(t->sync_clk);
+	if (div < 0)
+		return -EINVAL;
+
+	/*
+	 * See if we need to change the divider for waitmonitoringtime.
+	 *
+	 * Calculate GPMCFCLKDIVIDER independent of gpmc,sync-clk-ps in DT for
+	 * pure asynchronous accesses, i.e. both read and write asynchronous.
+	 * However, only do so if WAITMONITORINGTIME is actually used, i.e.
+	 * either WAITREADMONITORING or WAITWRITEMONITORING is set.
+	 *
+	 * This statement must not change div to scale async WAITMONITORINGTIME
+	 * to protect mixed synchronous and asynchronous accesses.
+	 *
+	 * We raise an error later if WAITMONITORINGTIME does not fit.
+	 */
+	if (!s->sync_read && !s->sync_write &&
+	    (s->wait_on_read || s->wait_on_write)
+	   ) {
+		div = gpmc_calc_waitmonitoring_divider(t->wait_monitoring);
+		if (div < 0) {
+			pr_err("%s: waitmonitoringtime %3d ns too large for greatest gpmcfclkdivider.\n",
+			       __func__,
+			       t->wait_monitoring
+			       );
+			return -ENXIO;
+		}
+	}
+
+	ret = 0;
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG2, 0, 3, 0, t->cs_on,
+				   GPMC_CD_FCLK, "cs_on");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG2, 8, 12, 0, t->cs_rd_off,
+				   GPMC_CD_FCLK, "cs_rd_off");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG2, 16, 20, 0, t->cs_wr_off,
+				   GPMC_CD_FCLK, "cs_wr_off");
+	if (ret)
+		return -ENXIO;
+
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 0, 3, 0, t->adv_on,
+				   GPMC_CD_FCLK, "adv_on");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 8, 12, 0, t->adv_rd_off,
+				   GPMC_CD_FCLK, "adv_rd_off");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 16, 20, 0, t->adv_wr_off,
+				   GPMC_CD_FCLK, "adv_wr_off");
+	if (ret)
+		return -ENXIO;
+
+	if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 4, 6, 0,
+					   t->adv_aad_mux_on, GPMC_CD_FCLK,
+					   "adv_aad_mux_on");
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 24, 26, 0,
+					   t->adv_aad_mux_rd_off, GPMC_CD_FCLK,
+					   "adv_aad_mux_rd_off");
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG3, 28, 30, 0,
+					   t->adv_aad_mux_wr_off, GPMC_CD_FCLK,
+					   "adv_aad_mux_wr_off");
+		if (ret)
+			return -ENXIO;
+	}
+
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 0, 3, 0, t->oe_on,
+				   GPMC_CD_FCLK, "oe_on");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 8, 12, 0, t->oe_off,
+				   GPMC_CD_FCLK, "oe_off");
+	if (gpmc_capability & GPMC_HAS_MUX_AAD) {
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 4, 6, 0,
+					   t->oe_aad_mux_on, GPMC_CD_FCLK,
+					   "oe_aad_mux_on");
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 13, 15, 0,
+					   t->oe_aad_mux_off, GPMC_CD_FCLK,
+					   "oe_aad_mux_off");
+	}
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 16, 19, 0, t->we_on,
+				   GPMC_CD_FCLK, "we_on");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG4, 24, 28, 0, t->we_off,
+				   GPMC_CD_FCLK, "we_off");
+	if (ret)
+		return -ENXIO;
+
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 0, 4, 0, t->rd_cycle,
+				   GPMC_CD_FCLK, "rd_cycle");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 8, 12, 0, t->wr_cycle,
+				   GPMC_CD_FCLK, "wr_cycle");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 16, 20, 0, t->access,
+				   GPMC_CD_FCLK, "access");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG5, 24, 27, 0,
+				   t->page_burst_access, GPMC_CD_FCLK,
+				   "page_burst_access");
+	if (ret)
+		return -ENXIO;
+
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 0, 3, 0,
+				   t->bus_turnaround, GPMC_CD_FCLK,
+				   "bus_turnaround");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 8, 11, 0,
+				   t->cycle2cycle_delay, GPMC_CD_FCLK,
+				   "cycle2cycle_delay");
+	if (ret)
+		return -ENXIO;
+
+	if (gpmc_capability & GPMC_HAS_WR_DATA_MUX_BUS) {
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 16, 19, 0,
+					   t->wr_data_mux_bus, GPMC_CD_FCLK,
+					   "wr_data_mux_bus");
+		if (ret)
+			return -ENXIO;
+	}
+	if (gpmc_capability & GPMC_HAS_WR_ACCESS) {
+		ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG6, 24, 28, 0,
+					   t->wr_access, GPMC_CD_FCLK,
+					   "wr_access");
+		if (ret)
+			return -ENXIO;
+	}
+
+	l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG1);
+	l &= ~0x03;
+	l |= (div - 1);
+	gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, l);
+
+	ret = 0;
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG1, 18, 19,
+				   GPMC_CONFIG1_WAITMONITORINGTIME_MAX,
+				   t->wait_monitoring, GPMC_CD_CLK,
+				   "wait_monitoring");
+	ret |= set_gpmc_timing_reg(cs, GPMC_CS_CONFIG1, 25, 26,
+				   GPMC_CONFIG1_CLKACTIVATIONTIME_MAX,
+				   t->clk_activation, GPMC_CD_FCLK,
+				   "clk_activation");
+	if (ret)
+		return -ENXIO;
+
+	if (IS_ENABLED(CONFIG_TI_GPMC_DEBUG)) {
+		pr_info("GPMC CS%d CLK period is %lu ns (div %d)\n",
+			cs, (div * gpmc_get_fclk_period()) / 1000, div);
+	}
+
+	gpmc_cs_bool_timings(cs, &t->bool_timings);
+	gpmc_cs_show_timings(cs, "after gpmc_set_timings");
+
+	return 0;
+}
+
+static int gpmc_cs_set_memconf(int cs, resource_size_t base, u32 size)
+{
+	u32 l;
+	u32 mask;
+
+	/*
+	 * Ensure that base address is aligned on a
+	 * boundary equal to or greater than size.
+	 */
+	if (base & (size - 1))
+		return -EINVAL;
+
+	base >>= GPMC_CHUNK_SHIFT;
+	mask = (1 << GPMC_SECTION_SHIFT) - size;
+	mask >>= GPMC_CHUNK_SHIFT;
+	mask <<= GPMC_CONFIG7_MASKADDRESS_OFFSET;
+
+	l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG7);
+	l &= ~GPMC_CONFIG7_MASK;
+	l |= base & GPMC_CONFIG7_BASEADDRESS_MASK;
+	l |= mask & GPMC_CONFIG7_MASKADDRESS_MASK;
+	l |= GPMC_CONFIG7_CSVALID;
+	gpmc_cs_write_reg(cs, GPMC_CS_CONFIG7, l);
+
+	return 0;
+}
+
+static void gpmc_cs_enable_mem(int cs)
+{
+	u32 l;
+
+	l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG7);
+	l |= GPMC_CONFIG7_CSVALID;
+	gpmc_cs_write_reg(cs, GPMC_CS_CONFIG7, l);
+}
+
+static void gpmc_cs_disable_mem(int cs)
+{
+	u32 l;
+
+	l = gpmc_cs_read_reg(cs, GPMC_CS_CONFIG7);
+	l &= ~GPMC_CONFIG7_CSVALID;
+	gpmc_cs_write_reg(cs, GPMC_CS_CONFIG7, l);
+}
+
+static void gpmc_cs_set_reserved(int cs, int reserved)
+{
+	struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+	gpmc->flags |= GPMC_CS_RESERVED;
+}
+
+static bool gpmc_cs_reserved(int cs)
+{
+	struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+	return gpmc->flags & GPMC_CS_RESERVED;
+}
+
+static unsigned long gpmc_mem_align(unsigned long size)
+{
+	int order;
+
+	size = (size - 1) >> (GPMC_CHUNK_SHIFT - 1);
+	order = GPMC_CHUNK_SHIFT - 1;
+	do {
+		size >>= 1;
+		order++;
+	} while (size);
+	size = 1 << order;
+	return size;
+}
+
+static int gpmc_cs_request(ofnode node, int cs, struct resource *res)
+{
+	int r = -1;
+	u32 size;
+	resource_size_t addr_base = res->start;
+
+	if (cs >= gpmc_cs_num) {
+		pr_err("%s: requested chip-select is disabled\n", __func__);
+		return -ENODEV;
+	}
+
+	size = gpmc_mem_align(resource_size(res));
+	if (size > (1 << GPMC_SECTION_SHIFT))
+		return -ENOMEM;
+
+	if (gpmc_cs_reserved(cs)) {
+		r = -EBUSY;
+		goto out;
+	}
+
+	if (addr_base & (SZ_16M - 1)) {
+		pr_err("CS region should be aligned to 16M boundary\n");
+		goto out;
+	}
+
+	/* Disable CS while changing base address and size mask */
+	gpmc_cs_disable_mem(cs);
+
+	r = gpmc_cs_set_memconf(cs, addr_base, size);
+	if (r < 0)
+		goto out;
+
+	/* Enable CS */
+	gpmc_cs_enable_mem(cs);
+	gpmc_cs_set_reserved(cs, 1);
+out:
+	return r;
+}
+
+static void gpmc_cs_free(int cs)
+{
+	if (cs >= gpmc_cs_num || cs < 0 || !gpmc_cs_reserved(cs)) {
+		pr_warn("Trying to free non-reserved GPMC CS%d\n", cs);
+		return;
+	}
+
+	gpmc_cs_disable_mem(cs);
+	gpmc_cs_set_reserved(cs, 0);
+}
+
+/**
+ * gpmc_configure - write request to configure gpmc
+ * @cmd: command type
+ * @wval: value to write
+ * @return status of the operation
+ */
+static int gpmc_configure(int cmd, int wval)
+{
+	u32 regval;
+
+	switch (cmd) {
+	case GPMC_CONFIG_WP:
+		regval = gpmc_read_reg(GPMC_CONFIG);
+		if (wval)
+			regval &= ~GPMC_CONFIG_WRITEPROTECT; /* WP is ON */
+		else
+			regval |= GPMC_CONFIG_WRITEPROTECT;  /* WP is OFF */
+		gpmc_write_reg(GPMC_CONFIG, regval);
+		break;
+
+	default:
+		pr_err("%s: command not supported\n", __func__);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * gpmc_cs_program_settings - programs non-timing related settings
+ * @cs:		GPMC chip-select to program
+ * @p:		pointer to GPMC settings structure
+ *
+ * Programs non-timing related settings for a GPMC chip-select, such as
+ * bus-width, burst configuration, etc. Function should be called once
+ * for each chip-select that is being used and must be called before
+ * calling gpmc_cs_set_timings() as timing parameters in the CONFIG1
+ * register will be initialised to zero by this function. Returns 0 on
+ * success and appropriate negative error code on failure.
+ */
+static int gpmc_cs_program_settings(int cs, struct gpmc_settings *p)
+{
+	u32 config1;
+
+	if (!p->device_width || p->device_width > GPMC_DEVWIDTH_16BIT) {
+		pr_err("%s: invalid width %d!", __func__, p->device_width);
+		return -EINVAL;
+	}
+
+	/* Address-data multiplexing not supported for NAND devices */
+	if (p->device_nand && p->mux_add_data) {
+		pr_err("%s: invalid configuration!\n", __func__);
+		return -EINVAL;
+	}
+
+	if (p->mux_add_data > GPMC_MUX_AD ||
+	    (p->mux_add_data == GPMC_MUX_AAD &&
+	     !(gpmc_capability & GPMC_HAS_MUX_AAD))) {
+		pr_err("%s: invalid multiplex configuration!\n", __func__);
+		return -EINVAL;
+	}
+
+	/* Page/burst mode supports lengths of 4, 8 and 16 bytes */
+	if (p->burst_read || p->burst_write) {
+		switch (p->burst_len) {
+		case GPMC_BURST_4:
+		case GPMC_BURST_8:
+		case GPMC_BURST_16:
+			break;
+		default:
+			pr_err("%s: invalid page/burst-length (%d)\n",
+			       __func__, p->burst_len);
+			return -EINVAL;
+		}
+	}
+
+	if (p->wait_pin > gpmc_nr_waitpins) {
+		pr_err("%s: invalid wait-pin (%d)\n", __func__, p->wait_pin);
+		return -EINVAL;
+	}
+
+	config1 = GPMC_CONFIG1_DEVICESIZE((p->device_width - 1));
+
+	if (p->sync_read)
+		config1 |= GPMC_CONFIG1_READTYPE_SYNC;
+	if (p->sync_write)
+		config1 |= GPMC_CONFIG1_WRITETYPE_SYNC;
+	if (p->wait_on_read)
+		config1 |= GPMC_CONFIG1_WAIT_READ_MON;
+	if (p->wait_on_write)
+		config1 |= GPMC_CONFIG1_WAIT_WRITE_MON;
+	if (p->wait_on_read || p->wait_on_write)
+		config1 |= GPMC_CONFIG1_WAIT_PIN_SEL(p->wait_pin);
+	if (p->device_nand)
+		config1	|= GPMC_CONFIG1_DEVICETYPE(GPMC_DEVICETYPE_NAND);
+	if (p->mux_add_data)
+		config1	|= GPMC_CONFIG1_MUXTYPE(p->mux_add_data);
+	if (p->burst_read)
+		config1 |= GPMC_CONFIG1_READMULTIPLE_SUPP;
+	if (p->burst_write)
+		config1 |= GPMC_CONFIG1_WRITEMULTIPLE_SUPP;
+	if (p->burst_read || p->burst_write) {
+		config1 |= GPMC_CONFIG1_PAGE_LEN(p->burst_len >> 3);
+		config1 |= p->burst_wrap ? GPMC_CONFIG1_WRAPBURST_SUPP : 0;
+	}
+
+	gpmc_cs_write_reg(cs, GPMC_CS_CONFIG1, config1);
+
+	return 0;
+}
+
+static void gpmc_cs_set_name(int cs, const char *name)
+{
+	struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+	gpmc->name = name;
+}
+
+static const char *gpmc_cs_get_name(int cs)
+{
+	struct gpmc_cs_data *gpmc = &gpmc_cs[cs];
+
+	return gpmc->name;
+}
+
+/**
+ * gpmc_read_settings_dt - read gpmc settings from device-tree
+ * @np:		pointer to device-tree node for a gpmc child device
+ * @p:		pointer to gpmc settings structure
+ *
+ * Reads the GPMC settings for a GPMC child device from device-tree and
+ * stores them in the GPMC settings structure passed. The GPMC settings
+ * structure is initialised to zero by this function and so any
+ * previously stored settings will be cleared.
+ */
+static void gpmc_read_settings_dt(ofnode np, struct gpmc_settings *p)
+{
+	memset(p, 0, sizeof(struct gpmc_settings));
+
+	p->sync_read = ofnode_read_bool(np, "gpmc,sync-read");
+	p->sync_write = ofnode_read_bool(np, "gpmc,sync-write");
+	ofnode_read_u32(np, "gpmc,device-width", &p->device_width);
+	ofnode_read_u32(np, "gpmc,mux-add-data", &p->mux_add_data);
+
+	if (!ofnode_read_u32(np, "gpmc,burst-length", &p->burst_len)) {
+		p->burst_wrap = ofnode_read_bool(np, "gpmc,burst-wrap");
+		p->burst_read = ofnode_read_bool(np, "gpmc,burst-read");
+		p->burst_write = ofnode_read_bool(np, "gpmc,burst-write");
+		if (!p->burst_read && !p->burst_write)
+			pr_warn("%s: page/burst-length set but not used!\n",
+				__func__);
+	}
+
+	if (!ofnode_read_u32(np, "gpmc,wait-pin", &p->wait_pin)) {
+		p->wait_on_read = ofnode_read_bool(np,
+						   "gpmc,wait-on-read");
+		p->wait_on_write = ofnode_read_bool(np,
+						    "gpmc,wait-on-write");
+		if (!p->wait_on_read && !p->wait_on_write)
+			pr_debug("%s: rd/wr wait monitoring not enabled!\n",
+				 __func__);
+	}
+}
+
+static void gpmc_read_timings_dt(ofnode np,
+				 struct gpmc_timings *gpmc_t)
+{
+	struct gpmc_bool_timings *p;
+
+	if (!gpmc_t)
+		return;
+
+	memset(gpmc_t, 0, sizeof(*gpmc_t));
+
+	/* minimum clock period for syncronous mode */
+	ofnode_read_u32(np, "gpmc,sync-clk-ps", &gpmc_t->sync_clk);
+
+	/* chip select timtings */
+	ofnode_read_u32(np, "gpmc,cs-on-ns", &gpmc_t->cs_on);
+	ofnode_read_u32(np, "gpmc,cs-rd-off-ns", &gpmc_t->cs_rd_off);
+	ofnode_read_u32(np, "gpmc,cs-wr-off-ns", &gpmc_t->cs_wr_off);
+
+	/* ADV signal timings */
+	ofnode_read_u32(np, "gpmc,adv-on-ns", &gpmc_t->adv_on);
+	ofnode_read_u32(np, "gpmc,adv-rd-off-ns", &gpmc_t->adv_rd_off);
+	ofnode_read_u32(np, "gpmc,adv-wr-off-ns", &gpmc_t->adv_wr_off);
+	ofnode_read_u32(np, "gpmc,adv-aad-mux-on-ns",
+			&gpmc_t->adv_aad_mux_on);
+	ofnode_read_u32(np, "gpmc,adv-aad-mux-rd-off-ns",
+			&gpmc_t->adv_aad_mux_rd_off);
+	ofnode_read_u32(np, "gpmc,adv-aad-mux-wr-off-ns",
+			&gpmc_t->adv_aad_mux_wr_off);
+
+	/* WE signal timings */
+	ofnode_read_u32(np, "gpmc,we-on-ns", &gpmc_t->we_on);
+	ofnode_read_u32(np, "gpmc,we-off-ns", &gpmc_t->we_off);
+
+	/* OE signal timings */
+	ofnode_read_u32(np, "gpmc,oe-on-ns", &gpmc_t->oe_on);
+	ofnode_read_u32(np, "gpmc,oe-off-ns", &gpmc_t->oe_off);
+	ofnode_read_u32(np, "gpmc,oe-aad-mux-on-ns",
+			&gpmc_t->oe_aad_mux_on);
+	ofnode_read_u32(np, "gpmc,oe-aad-mux-off-ns",
+			&gpmc_t->oe_aad_mux_off);
+
+	/* access and cycle timings */
+	ofnode_read_u32(np, "gpmc,page-burst-access-ns",
+			&gpmc_t->page_burst_access);
+	ofnode_read_u32(np, "gpmc,access-ns", &gpmc_t->access);
+	ofnode_read_u32(np, "gpmc,rd-cycle-ns", &gpmc_t->rd_cycle);
+	ofnode_read_u32(np, "gpmc,wr-cycle-ns", &gpmc_t->wr_cycle);
+	ofnode_read_u32(np, "gpmc,bus-turnaround-ns",
+			&gpmc_t->bus_turnaround);
+	ofnode_read_u32(np, "gpmc,cycle2cycle-delay-ns",
+			&gpmc_t->cycle2cycle_delay);
+	ofnode_read_u32(np, "gpmc,wait-monitoring-ns",
+			&gpmc_t->wait_monitoring);
+	ofnode_read_u32(np, "gpmc,clk-activation-ns",
+			&gpmc_t->clk_activation);
+
+	/* only applicable to OMAP3+ */
+	ofnode_read_u32(np, "gpmc,wr-access-ns", &gpmc_t->wr_access);
+	ofnode_read_u32(np, "gpmc,wr-data-mux-bus-ns",
+			&gpmc_t->wr_data_mux_bus);
+
+	/* bool timing parameters */
+	p = &gpmc_t->bool_timings;
+
+	p->cycle2cyclediffcsen =
+		ofnode_read_bool(np, "gpmc,cycle2cycle-diffcsen");
+	p->cycle2cyclesamecsen =
+		ofnode_read_bool(np, "gpmc,cycle2cycle-samecsen");
+	p->we_extra_delay = ofnode_read_bool(np, "gpmc,we-extra-delay");
+	p->oe_extra_delay = ofnode_read_bool(np, "gpmc,oe-extra-delay");
+	p->adv_extra_delay = ofnode_read_bool(np, "gpmc,adv-extra-delay");
+	p->cs_extra_delay = ofnode_read_bool(np, "gpmc,cs-extra-delay");
+	p->time_para_granularity =
+		ofnode_read_bool(np, "gpmc,time-para-granularity");
+}
+
+/**
+ * gpmc_probe_generic_child - configures the gpmc for a child device
+ * @dev:	pointer to gpmc platform device
+ * @child:	pointer to device-tree node for child device
+ *
+ * Allocates and configures a GPMC chip-select for a child device.
+ * Returns 0 on success and appropriate negative error code on failure.
+ */
+static int gpmc_probe_generic_child(struct udevice *dev,
+				    ofnode child)
+{
+	struct gpmc_settings gpmc_s;
+	struct gpmc_timings gpmc_t;
+	struct resource res;
+	const char *name;
+	int ret;
+	u32 val, cs;
+
+	if (ofnode_read_u32(child, "reg", &cs) < 0) {
+		dev_err(dev, "can't get reg property of child %s\n",
+			ofnode_get_name(child));
+		return -ENODEV;
+	}
+
+	if (ofnode_read_resource(child, 0, &res) < 0) {
+		dev_err(dev, "%s has malformed 'reg' property\n",
+			ofnode_get_name(child));
+		return -ENODEV;
+	}
+
+	/*
+	 * Check if we have multiple instances of the same device
+	 * on a single chip select. If so, use the already initialized
+	 * timings.
+	 */
+	name = gpmc_cs_get_name(cs);
+	if (name && !strcmp(name, ofnode_get_name(child)))
+		goto no_timings;
+
+	ret = gpmc_cs_request(child, cs, &res);
+	if (ret < 0) {
+		dev_err(dev, "cannot request GPMC CS %d\n", cs);
+		return ret;
+	}
+	gpmc_cs_set_name(cs, ofnode_get_name(child));
+
+	gpmc_read_settings_dt(child, &gpmc_s);
+	gpmc_read_timings_dt(child, &gpmc_t);
+
+	/*
+	 * For some GPMC devices we still need to rely on the bootloader
+	 * timings because the devices can be connected via FPGA.
+	 * REVISIT: Add timing support from slls644g.pdf.
+	 */
+	if (!gpmc_t.cs_rd_off) {
+		pr_warn("enable GPMC debug to configure .dts timings for CS%i\n",
+			cs);
+		gpmc_cs_show_timings(cs,
+				     "please add GPMC bootloader timings to .dts");
+		goto no_timings;
+	}
+
+	/* CS must be disabled while making changes to gpmc configuration */
+	gpmc_cs_disable_mem(cs);
+
+	if (!ofnode_read_u32(child, "nand-bus-width", &val)) {
+		/* NAND specific setup */
+		ofnode_read_u32(child, "nand-bus-width", &val);
+		switch (val) {
+		case 8:
+			gpmc_s.device_width = GPMC_DEVWIDTH_8BIT;
+			break;
+		case 16:
+			gpmc_s.device_width = GPMC_DEVWIDTH_16BIT;
+			break;
+		default:
+			dev_err(dev, "%s: invalid 'nand-bus-width'\n",
+				ofnode_get_name(child));
+			ret = -EINVAL;
+			goto err;
+		}
+
+		/* disable write protect */
+		gpmc_configure(GPMC_CONFIG_WP, 0);
+		gpmc_s.device_nand = true;
+	} else {
+		ret = ofnode_read_u32(child, "bank-width",
+				      &gpmc_s.device_width);
+		if (ret < 0 && !gpmc_s.device_width) {
+			dev_err(dev,
+				"%s has no 'gpmc,device-width' property\n",
+				ofnode_get_name(child));
+			goto err;
+		}
+	}
+
+	gpmc_cs_show_timings(cs, "before gpmc_cs_program_settings");
+
+	ret = gpmc_cs_program_settings(cs, &gpmc_s);
+	if (ret < 0)
+		goto err;
+
+	ret = gpmc_cs_set_timings(cs, &gpmc_t, &gpmc_s);
+	if (ret) {
+		dev_err(dev, "failed to set gpmc timings for: %s\n",
+			ofnode_get_name(child));
+		goto err;
+	}
+
+	/* Clear limited address i.e. enable A26-A11 */
+	val = gpmc_read_reg(GPMC_CONFIG);
+	val &= ~GPMC_CONFIG_LIMITEDADDRESS;
+	gpmc_write_reg(GPMC_CONFIG, val);
+
+	/* Enable CS region */
+	gpmc_cs_enable_mem(cs);
+
+no_timings:
+
+	return 0;
+
+err:
+	gpmc_cs_free(cs);
+
+	return ret;
+}
+
+static void gpmc_probe_dt_children(struct udevice *dev)
+{
+	int ret;
+	ofnode child;
+
+	ofnode_for_each_subnode(child, dev_ofnode(dev)) {
+		ret = gpmc_probe_generic_child(dev, child);
+		if (ret) {
+			dev_err(dev, "Cannot parse child %s:%d",
+				ofnode_get_name(child), ret);
+		}
+	}
+}
+
+static int gpmc_parse_dt(struct udevice *dev, struct ti_gpmc *gpmc)
+{
+	int ret;
+	u32 val;
+
+	ret = ofnode_read_u32(dev_ofnode(dev), "gpmc,num-cs",
+			      &val);
+	if (ret < 0) {
+		pr_err("%s: number of chip-selects not defined\n", __func__);
+		return ret;
+	} else if (val < 1) {
+		pr_err("%s: all chip-selects are disabled\n", __func__);
+		return -EINVAL;
+	} else if (val > GPMC_CS_NUM) {
+		pr_err("%s: number of supported chip-selects cannot be > %d\n",
+		       __func__, GPMC_CS_NUM);
+		return -EINVAL;
+	}
+
+	gpmc->cs_num = val;
+	gpmc_cs_num = val;
+
+	ret = ofnode_read_u32(dev_ofnode(dev), "gpmc,num-waitpins",
+			      &gpmc->nr_waitpins);
+	if (ret < 0) {
+		pr_err("%s: number of wait pins not found!\n", __func__);
+		return ret;
+	}
+
+	gpmc_nr_waitpins = gpmc->nr_waitpins;
+
+	return 0;
+}
+
+static int gpmc_probe(struct udevice *dev)
+{
+	struct ti_gpmc *priv = dev_get_priv(dev);
+	int ret;
+	struct resource res;
+
+	ret = dev_read_resource_byname(dev, "cfg", &res);
+	if (ret) {
+		/* Legacy DT */
+		dev_read_resource(dev, 0, &res);
+		priv->base = devm_ioremap(dev, res.start, resource_size(&res));
+
+		priv->data.start = GPMC_MEM_START;
+		priv->data.end = GPMC_MEM_END;
+	} else {
+		priv->base = devm_ioremap(dev, res.start, resource_size(&res));
+		ret = dev_read_resource_byname(dev, "data", &res);
+		if (ret)
+			return -ENOENT;
+
+		priv->data = res;
+	}
+
+	if (!priv->base)
+		return -ENOMEM;
+
+	gpmc_cfg = (struct gpmc *)priv->base;
+	gpmc_base = priv->base;
+
+	priv->l3_clk = devm_clk_get(dev, "fck");
+	if (IS_ERR(priv->l3_clk))
+		return PTR_ERR(priv->l3_clk);
+
+	if (!clk_get_rate(priv->l3_clk))
+		return -EINVAL;
+
+	gpmc_l3_clk = priv->l3_clk;
+
+	ret = gpmc_parse_dt(dev, priv);
+	if (ret)
+		return ret;
+
+	priv->capability_flags = dev->driver->of_match->data;
+	gpmc_capability = priv->capability_flags;
+
+	gpmc_probe_dt_children(dev);
+
+	return 0;
+}
+
+#define GPMC_DATA_REV2_4 0
+#define GPMC_DATA_REV5 (GPMC_HAS_WR_ACCESS | GPMC_HAS_WR_DATA_MUX_BUS)
+#define GPMC_DATA_REV6 (GPMC_HAS_WR_ACCESS | GPMC_HAS_WR_DATA_MUX_BUS | GPMC_HAS_MUX_AAD)
+
+static const struct udevice_id gpmc_dt_ids[] = {
+	{ .compatible = "ti,am64-gpmc", .data = GPMC_DATA_REV6, },
+	{ .compatible = "ti,am3352-gpmc", .data = GPMC_DATA_REV5, },
+	{ .compatible = "ti,omap2420-gpmc", .data = GPMC_DATA_REV2_4, },
+	{ .compatible = "ti,omap2430-gpmc", .data = GPMC_DATA_REV2_4, },
+	{ .compatible = "ti,omap3430-gpmc", .data = GPMC_DATA_REV5, },
+	{ .compatible = "ti,omap4430-gpmc", .data = GPMC_DATA_REV6, },
+	{ } /* sentinel */
+};
+
+U_BOOT_DRIVER(ti_gpmc) = {
+	.name   = "ti-gpmc",
+	.id     = UCLASS_MEMORY,
+	.of_match = gpmc_dt_ids,
+	.probe  = gpmc_probe,
+	.flags  = DM_FLAG_ALLOC_PRIV_DMA,
+};
diff --git a/drivers/memory/ti-gpmc.h b/drivers/memory/ti-gpmc.h
new file mode 100644
index 0000000000..90f8e656c8
--- /dev/null
+++ b/drivers/memory/ti-gpmc.h
@@ -0,0 +1,298 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Texas Instruments GPMC Driver
+ *
+ * Copyright (C) 2021 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+/* GPMC register offsets */
+#define GPMC_REVISION		0x00
+#define GPMC_SYSCONFIG		0x10
+#define GPMC_SYSSTATUS		0x14
+#define GPMC_IRQSTATUS		0x18
+#define GPMC_IRQENABLE		0x1c
+#define GPMC_TIMEOUT_CONTROL	0x40
+#define GPMC_ERR_ADDRESS	0x44
+#define GPMC_ERR_TYPE		0x48
+#define GPMC_CONFIG		0x50
+#define GPMC_STATUS		0x54
+#define GPMC_PREFETCH_CONFIG1	0x1e0
+#define GPMC_PREFETCH_CONFIG2	0x1e4
+#define GPMC_PREFETCH_CONTROL	0x1ec
+#define GPMC_PREFETCH_STATUS	0x1f0
+#define GPMC_ECC_CONFIG		0x1f4
+#define GPMC_ECC_CONTROL	0x1f8
+#define GPMC_ECC_SIZE_CONFIG	0x1fc
+#define GPMC_ECC1_RESULT        0x200
+#define GPMC_ECC_BCH_RESULT_0   0x240   /* not available on OMAP2 */
+#define	GPMC_ECC_BCH_RESULT_1	0x244	/* not available on OMAP2 */
+#define	GPMC_ECC_BCH_RESULT_2	0x248	/* not available on OMAP2 */
+#define	GPMC_ECC_BCH_RESULT_3	0x24c	/* not available on OMAP2 */
+#define	GPMC_ECC_BCH_RESULT_4	0x300	/* not available on OMAP2 */
+#define	GPMC_ECC_BCH_RESULT_5	0x304	/* not available on OMAP2 */
+#define	GPMC_ECC_BCH_RESULT_6	0x308	/* not available on OMAP2 */
+
+/* GPMC ECC control settings */
+#define GPMC_ECC_CTRL_ECCCLEAR		0x100
+#define GPMC_ECC_CTRL_ECCDISABLE	0x000
+#define GPMC_ECC_CTRL_ECCREG1		0x001
+#define GPMC_ECC_CTRL_ECCREG2		0x002
+#define GPMC_ECC_CTRL_ECCREG3		0x003
+#define GPMC_ECC_CTRL_ECCREG4		0x004
+#define GPMC_ECC_CTRL_ECCREG5		0x005
+#define GPMC_ECC_CTRL_ECCREG6		0x006
+#define GPMC_ECC_CTRL_ECCREG7		0x007
+#define GPMC_ECC_CTRL_ECCREG8		0x008
+#define GPMC_ECC_CTRL_ECCREG9		0x009
+
+#define GPMC_CONFIG_LIMITEDADDRESS		BIT(1)
+
+#define GPMC_STATUS_EMPTYWRITEBUFFERSTATUS	BIT(0)
+
+#define	GPMC_CONFIG2_CSEXTRADELAY		BIT(7)
+#define	GPMC_CONFIG3_ADVEXTRADELAY		BIT(7)
+#define	GPMC_CONFIG4_OEEXTRADELAY		BIT(7)
+#define	GPMC_CONFIG4_WEEXTRADELAY		BIT(23)
+#define	GPMC_CONFIG6_CYCLE2CYCLEDIFFCSEN	BIT(6)
+#define	GPMC_CONFIG6_CYCLE2CYCLESAMECSEN	BIT(7)
+
+#define GPMC_CS0_OFFSET		0x60
+#define GPMC_CS_SIZE		0x30
+#define	GPMC_BCH_SIZE		0x10
+
+/*
+ * The first 1MB of GPMC address space is typically mapped to
+ * the internal ROM. Never allocate the first page, to
+ * facilitate bug detection; even if we didn't boot from ROM.
+ * As GPMC minimum partition size is 16MB we can only start from
+ * there.
+ */
+#define GPMC_MEM_START		0x1000000
+#define GPMC_MEM_END		0x3FFFFFFF
+
+#define GPMC_CHUNK_SHIFT	24		/* 16 MB */
+#define GPMC_SECTION_SHIFT	28		/* 128 MB */
+
+#define CS_NUM_SHIFT		24
+#define ENABLE_PREFETCH		(0x1 << 7)
+#define DMA_MPU_MODE		2
+
+#define	GPMC_REVISION_MAJOR(l)		(((l) >> 4) & 0xf)
+#define	GPMC_REVISION_MINOR(l)		((l) & 0xf)
+
+#define	GPMC_HAS_WR_ACCESS		0x1
+#define	GPMC_HAS_WR_DATA_MUX_BUS	0x2
+#define	GPMC_HAS_MUX_AAD		0x4
+
+#define GPMC_NR_WAITPINS		4
+
+#define GPMC_CS_CONFIG1		0x00
+#define GPMC_CS_CONFIG2		0x04
+#define GPMC_CS_CONFIG3		0x08
+#define GPMC_CS_CONFIG4		0x0c
+#define GPMC_CS_CONFIG5		0x10
+#define GPMC_CS_CONFIG6		0x14
+#define GPMC_CS_CONFIG7		0x18
+#define GPMC_CS_NAND_COMMAND	0x1c
+#define GPMC_CS_NAND_ADDRESS	0x20
+#define GPMC_CS_NAND_DATA	0x24
+
+/* Control Commands */
+#define GPMC_CONFIG_RDY_BSY	0x00000001
+#define GPMC_CONFIG_DEV_SIZE	0x00000002
+#define GPMC_CONFIG_DEV_TYPE	0x00000003
+
+#define GPMC_CONFIG_WP          0x00000005
+
+#define GPMC_CONFIG1_WRAPBURST_SUPP     BIT(31)
+#define GPMC_CONFIG1_READMULTIPLE_SUPP  BIT(30)
+#define GPMC_CONFIG1_READTYPE_ASYNC     (0 << 29)
+#define GPMC_CONFIG1_READTYPE_SYNC      BIT(29)
+#define GPMC_CONFIG1_WRITEMULTIPLE_SUPP BIT(28)
+#define GPMC_CONFIG1_WRITETYPE_ASYNC    (0 << 27)
+#define GPMC_CONFIG1_WRITETYPE_SYNC     BIT(27)
+#define GPMC_CONFIG1_CLKACTIVATIONTIME(val) (((val) & 3) << 25)
+/** CLKACTIVATIONTIME Max Ticks */
+#define GPMC_CONFIG1_CLKACTIVATIONTIME_MAX 2
+#define GPMC_CONFIG1_PAGE_LEN(val)      (((val) & 3) << 23)
+/** ATTACHEDDEVICEPAGELENGTH Max Value */
+#define GPMC_CONFIG1_ATTACHEDDEVICEPAGELENGTH_MAX 2
+#define GPMC_CONFIG1_WAIT_READ_MON      BIT(22)
+#define GPMC_CONFIG1_WAIT_WRITE_MON     BIT(21)
+#define GPMC_CONFIG1_WAIT_MON_TIME(val) (((val) & 3) << 18)
+/** WAITMONITORINGTIME Max Ticks */
+#define GPMC_CONFIG1_WAITMONITORINGTIME_MAX  2
+#define GPMC_CONFIG1_WAIT_PIN_SEL(val)  (((val) & 3) << 16)
+#define GPMC_CONFIG1_DEVICESIZE(val)    (((val) & 3) << 12)
+#define GPMC_CONFIG1_DEVICESIZE_16      GPMC_CONFIG1_DEVICESIZE(1)
+/** DEVICESIZE Max Value */
+#define GPMC_CONFIG1_DEVICESIZE_MAX     1
+#define GPMC_CONFIG1_DEVICETYPE(val)    (((val) & 3) << 10)
+#define GPMC_CONFIG1_DEVICETYPE_NOR     GPMC_CONFIG1_DEVICETYPE(0)
+#define GPMC_CONFIG1_MUXTYPE(val)       (((val) & 3) << 8)
+#define GPMC_CONFIG1_TIME_PARA_GRAN     BIT(4)
+#define GPMC_CONFIG1_FCLK_DIV(val)      ((val) & 3)
+#define GPMC_CONFIG1_FCLK_DIV2          (GPMC_CONFIG1_FCLK_DIV(1))
+#define GPMC_CONFIG1_FCLK_DIV3          (GPMC_CONFIG1_FCLK_DIV(2))
+#define GPMC_CONFIG1_FCLK_DIV4          (GPMC_CONFIG1_FCLK_DIV(3))
+#define GPMC_CONFIG7_CSVALID		BIT(6)
+
+#define GPMC_CONFIG7_BASEADDRESS_MASK	0x3f
+#define GPMC_CONFIG7_CSVALID_MASK	BIT(6)
+#define GPMC_CONFIG7_MASKADDRESS_OFFSET	8
+#define GPMC_CONFIG7_MASKADDRESS_MASK	(0xf << GPMC_CONFIG7_MASKADDRESS_OFFSET)
+/* All CONFIG7 bits except reserved bits */
+#define GPMC_CONFIG7_MASK		(GPMC_CONFIG7_BASEADDRESS_MASK | \
+					 GPMC_CONFIG7_CSVALID_MASK |     \
+					 GPMC_CONFIG7_MASKADDRESS_MASK)
+
+#define GPMC_DEVICETYPE_NOR		0
+#define GPMC_DEVICETYPE_NAND		2
+#define GPMC_CONFIG_WRITEPROTECT	0x00000010
+#define WR_RD_PIN_MONITORING		0x00600000
+
+/* ECC commands */
+#define GPMC_ECC_READ		0 /* Reset Hardware ECC for read */
+#define GPMC_ECC_WRITE		1 /* Reset Hardware ECC for write */
+#define GPMC_ECC_READSYN	2 /* Reset before syndrom is read back */
+
+#define	GPMC_NR_NAND_IRQS	2 /* number of NAND specific IRQs */
+
+/* bool type time settings */
+struct gpmc_bool_timings {
+	bool cycle2cyclediffcsen;
+	bool cycle2cyclesamecsen;
+	bool we_extra_delay;
+	bool oe_extra_delay;
+	bool adv_extra_delay;
+	bool cs_extra_delay;
+	bool time_para_granularity;
+};
+
+/*
+ * Note that all values in this struct are in nanoseconds except sync_clk
+ * (which is in picoseconds), while the register values are in gpmc_fck cycles.
+ */
+struct gpmc_timings {
+	/* Minimum clock period for synchronous mode (in picoseconds) */
+	u32 sync_clk;
+
+	/* Chip-select signal timings corresponding to GPMC_CS_CONFIG2 */
+	u32 cs_on;		/* Assertion time */
+	u32 cs_rd_off;		/* Read deassertion time */
+	u32 cs_wr_off;		/* Write deassertion time */
+
+	/* ADV signal timings corresponding to GPMC_CONFIG3 */
+	u32 adv_on;		/* Assertion time */
+	u32 adv_rd_off;		/* Read deassertion time */
+	u32 adv_wr_off;		/* Write deassertion time */
+	u32 adv_aad_mux_on;	/* ADV assertion time for AAD */
+	u32 adv_aad_mux_rd_off;	/* ADV read deassertion time for AAD */
+	u32 adv_aad_mux_wr_off;	/* ADV write deassertion time for AAD */
+
+	/* WE signals timings corresponding to GPMC_CONFIG4 */
+	u32 we_on;		/* WE assertion time */
+	u32 we_off;		/* WE deassertion time */
+
+	/* OE signals timings corresponding to GPMC_CONFIG4 */
+	u32 oe_on;		/* OE assertion time */
+	u32 oe_off;		/* OE deassertion time */
+	u32 oe_aad_mux_on;	/* OE assertion time for AAD */
+	u32 oe_aad_mux_off;	/* OE deassertion time for AAD */
+
+	/* Access time and cycle time timings corresponding to GPMC_CONFIG5 */
+	u32 page_burst_access;	/* Multiple access word delay */
+	u32 access;		/* Start-cycle to first data valid delay */
+	u32 rd_cycle;		/* Total read cycle time */
+	u32 wr_cycle;		/* Total write cycle time */
+
+	u32 bus_turnaround;
+	u32 cycle2cycle_delay;
+
+	u32 wait_monitoring;
+	u32 clk_activation;
+
+	/* The following are only on OMAP3430 */
+	u32 wr_access;		/* WRACCESSTIME */
+	u32 wr_data_mux_bus;	/* WRDATAONADMUXBUS */
+
+	struct gpmc_bool_timings bool_timings;
+};
+
+/* Device timings in picoseconds */
+struct gpmc_device_timings {
+	u32 t_ceasu;	/* address setup to CS valid */
+	u32 t_avdasu;	/* address setup to ADV valid */
+	/* XXX: try to combine t_avdp_r & t_avdp_w. Issue is
+	 * of tusb using these timings even for sync whilst
+	 * ideally for adv_rd/(wr)_off it should have considered
+	 * t_avdh instead. This indirectly necessitates r/w
+	 * variations of t_avdp as it is possible to have one
+	 * sync & other async
+	 */
+	u32 t_avdp_r;	/* ADV low time (what about t_cer ?) */
+	u32 t_avdp_w;
+	u32 t_aavdh;	/* address hold time */
+	u32 t_oeasu;	/* address setup to OE valid */
+	u32 t_aa;	/* access time from ADV assertion */
+	u32 t_iaa;	/* initial access time */
+	u32 t_oe;	/* access time from OE assertion */
+	u32 t_ce;	/* access time from CS asertion */
+	u32 t_rd_cycle;	/* read cycle time */
+	u32 t_cez_r;	/* read CS deassertion to high Z */
+	u32 t_cez_w;	/* write CS deassertion to high Z */
+	u32 t_oez;	/* OE deassertion to high Z */
+	u32 t_weasu;	/* address setup to WE valid */
+	u32 t_wpl;	/* write assertion time */
+	u32 t_wph;	/* write deassertion time */
+	u32 t_wr_cycle;	/* write cycle time */
+
+	u32 clk;
+	u32 t_bacc;	/* burst access valid clock to output delay */
+	u32 t_ces;	/* CS setup time to clk */
+	u32 t_avds;	/* ADV setup time to clk */
+	u32 t_avdh;	/* ADV hold time from clk */
+	u32 t_ach;	/* address hold time from clk */
+	u32 t_rdyo;	/* clk to ready valid */
+
+	u32 t_ce_rdyz;	/* XXX: description ?, or use t_cez instead */
+	u32 t_ce_avd;	/* CS on to ADV on delay */
+
+	/* XXX: check the possibility of combining
+	 * cyc_aavhd_oe & cyc_aavdh_we
+	 */
+	u8 cyc_aavdh_oe;/* read address hold time in cycles */
+	u8 cyc_aavdh_we;/* write address hold time in cycles */
+	u8 cyc_oe;	/* access time from OE assertion in cycles */
+	u8 cyc_wpl;	/* write deassertion time in cycles */
+	u32 cyc_iaa;	/* initial access time in cycles */
+
+	/* extra delays */
+	bool ce_xdelay;
+	bool avd_xdelay;
+	bool oe_xdelay;
+	bool we_xdelay;
+};
+
+#define GPMC_BURST_4			4	/* 4 word burst */
+#define GPMC_BURST_8			8	/* 8 word burst */
+#define GPMC_BURST_16			16	/* 16 word burst */
+#define GPMC_DEVWIDTH_8BIT		1	/* 8-bit device width */
+#define GPMC_DEVWIDTH_16BIT		2	/* 16-bit device width */
+#define GPMC_MUX_AAD			1	/* Addr-Addr-Data multiplex */
+#define GPMC_MUX_AD			2	/* Addr-Data multiplex */
+
+struct gpmc_settings {
+	bool burst_wrap;	/* enables wrap bursting */
+	bool burst_read;	/* enables read page/burst mode */
+	bool burst_write;	/* enables write page/burst mode */
+	bool device_nand;	/* device is NAND */
+	bool sync_read;		/* enables synchronous reads */
+	bool sync_write;	/* enables synchronous writes */
+	bool wait_on_read;	/* monitor wait on reads */
+	bool wait_on_write;	/* monitor wait on writes */
+	u32 burst_len;		/* page/burst length */
+	u32 device_width;	/* device bus width (8 or 16 bit) */
+	u32 mux_add_data;	/* multiplex address & data */
+	u32 wait_pin;		/* wait-pin to be used */
+};
diff --git a/include/linux/mtd/omap_gpmc.h b/include/linux/mtd/omap_gpmc.h
index 864b05e432..f08e700a1d 100644
--- a/include/linux/mtd/omap_gpmc.h
+++ b/include/linux/mtd/omap_gpmc.h
@@ -8,6 +8,9 @@
 #ifndef __ASM_OMAP_GPMC_H
 #define __ASM_OMAP_GPMC_H
 
+/* Maximum Number of Chip Selects */
+#define GPMC_CS_NUM	8
+
 #define GPMC_BUF_EMPTY	0
 #define GPMC_BUF_FULL	1
 #define GPMC_MAX_SECTORS	8