rockchip: px30: Add support for using UART3 as debug UART

Some generic PX30 SoMs found in the wild use UART3 as their debug output
instead of UART2 (used for MMC) and UART5.

Make it possible to use UART3 as early debug output, with the associated
clock and pinmux configuration. Two sets of output pins are supported (M0/M1).

Future users should also note that the pinmux default in the dts is to use
the M1 pins while the Kconfig option takes M0 as a default.

Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/arch/arm/mach-rockchip/px30/px30.c b/arch/arm/mach-rockchip/px30/px30.c
index a2241cfc60..5014ee83d7 100644
--- a/arch/arm/mach-rockchip/px30/px30.c
+++ b/arch/arm/mach-rockchip/px30/px30.c
@@ -37,6 +37,7 @@ static struct mm_region px30_mem_map[] = {
 struct mm_region *mem_map = px30_mem_map;
 
 #define PMU_PWRDN_CON			0xff000018
+#define PMUGRF_BASE			0xff010000
 #define GRF_BASE			0xff140000
 #define CRU_BASE			0xff2b0000
 #define VIDEO_PHY_BASE			0xff2e0000
@@ -49,6 +50,23 @@ struct mm_region *mem_map = px30_mem_map;
 
 #define QOS_PRIORITY_LEVEL(h, l)	((((h) & 3) << 8) | ((l) & 3))
 
+/* GRF_GPIO1BH_IOMUX */
+enum {
+	GPIO1B7_SHIFT		= 12,
+	GPIO1B7_MASK		= 0xf << GPIO1B7_SHIFT,
+	GPIO1B7_GPIO		= 0,
+	GPIO1B7_FLASH_RDN,
+	GPIO1B7_UART3_RXM1,
+	GPIO1B7_SPI0_CLK,
+
+	GPIO1B6_SHIFT		= 8,
+	GPIO1B6_MASK		= 0xf << GPIO1B6_SHIFT,
+	GPIO1B6_GPIO		= 0,
+	GPIO1B6_FLASH_CS1,
+	GPIO1B6_UART3_TXM1,
+	GPIO1B6_SPI0_CSN,
+};
+
 /* GRF_GPIO1CL_IOMUX */
 enum {
 	GPIO1C1_SHIFT		= 4,
@@ -128,6 +146,23 @@ enum {
 	GPIO3A1_UART5_RX	= 4,
 };
 
+/* PMUGRF_GPIO0CL_IOMUX */
+enum {
+	GPIO0C1_SHIFT		= 2,
+	GPIO0C1_MASK		= 0x3 << GPIO0C1_SHIFT,
+	GPIO0C1_GPIO		= 0,
+	GPIO0C1_PWM_3,
+	GPIO0C1_UART3_RXM0,
+	GPIO0C1_PMU_DEBUG4,
+
+	GPIO0C0_SHIFT		= 0,
+	GPIO0C0_MASK		= 0x3 << GPIO0C0_SHIFT,
+	GPIO0C0_GPIO		= 0,
+	GPIO0C0_PWM_1,
+	GPIO0C0_UART3_TXM0,
+	GPIO0C0_PMU_DEBUG3,
+};
+
 int arch_cpu_init(void)
 {
 	static struct px30_grf * const grf = (void *)GRF_BASE;
@@ -175,6 +210,11 @@ int arch_cpu_init(void)
 #ifdef CONFIG_DEBUG_UART_BOARD_INIT
 void board_debug_uart_init(void)
 {
+#if defined(CONFIG_DEBUG_UART_BASE) && \
+	(CONFIG_DEBUG_UART_BASE == 0xff168000) && \
+	(CONFIG_DEBUG_UART_CHANNEL != 1)
+	static struct px30_pmugrf * const pmugrf = (void *)PMUGRF_BASE;
+#endif
 	static struct px30_grf * const grf = (void *)GRF_BASE;
 	static struct px30_cru * const cru = (void *)CRU_BASE;
 
@@ -191,6 +231,43 @@ void board_debug_uart_init(void)
 		     GPIO1C1_MASK | GPIO1C0_MASK,
 		     GPIO1C1_UART1_TX << GPIO1C1_SHIFT |
 		     GPIO1C0_UART1_RX << GPIO1C0_SHIFT);
+#elif defined(CONFIG_DEBUG_UART_BASE) && (CONFIG_DEBUG_UART_BASE == 0xff168000)
+	/* GRF_IOFUNC_CON0 */
+	enum {
+		CON_IOMUX_UART3SEL_SHIFT	= 9,
+		CON_IOMUX_UART3SEL_MASK = 1 << CON_IOMUX_UART3SEL_SHIFT,
+		CON_IOMUX_UART3SEL_M0	= 0,
+		CON_IOMUX_UART3SEL_M1,
+	};
+
+	/* uart_sel_clk default select 24MHz */
+	rk_clrsetreg(&cru->clksel_con[40],
+		     UART3_PLL_SEL_MASK | UART3_DIV_CON_MASK,
+		     UART3_PLL_SEL_24M << UART3_PLL_SEL_SHIFT | 0);
+	rk_clrsetreg(&cru->clksel_con[41],
+		     UART3_CLK_SEL_MASK,
+		     UART3_CLK_SEL_UART3 << UART3_CLK_SEL_SHIFT);
+
+#if (CONFIG_DEBUG_UART_CHANNEL == 1)
+	rk_clrsetreg(&grf->iofunc_con0,
+		     CON_IOMUX_UART3SEL_MASK,
+		     CON_IOMUX_UART3SEL_M1 << CON_IOMUX_UART3SEL_SHIFT);
+
+	rk_clrsetreg(&grf->gpio1bh_iomux,
+		     GPIO1B7_MASK | GPIO1B6_MASK,
+		     GPIO1B7_UART3_RXM1 << GPIO1B7_SHIFT |
+		     GPIO1B6_UART3_TXM1 << GPIO1B6_SHIFT);
+#else
+	rk_clrsetreg(&grf->iofunc_con0,
+		     CON_IOMUX_UART3SEL_MASK,
+		     CON_IOMUX_UART3SEL_M0 << CON_IOMUX_UART3SEL_SHIFT);
+
+	rk_clrsetreg(&pmugrf->gpio0cl_iomux,
+		     GPIO0C1_MASK | GPIO0C0_MASK,
+		     GPIO0C1_UART3_RXM0 << GPIO0C1_SHIFT |
+		     GPIO0C0_UART3_TXM0 << GPIO0C0_SHIFT);
+#endif /* CONFIG_DEBUG_UART_CHANNEL == 1 */
+
 #elif defined(CONFIG_DEBUG_UART_BASE) && (CONFIG_DEBUG_UART_BASE == 0xff178000)
 	/* uart_sel_clk default select 24MHz */
 	rk_clrsetreg(&cru->clksel_con[46],