stm32: add SPI master for STM32H7

Add the driver for the new silicon used in STM32H7 SPI controller,
including its bad errata when used with DMA.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=none
BUG=b:67081508
TEST=on ZerbleBarn, do finger image acquisition on the SPI fingerprint
sensor.

Change-Id: Ieaf4a09e961d3e0ef78b58886c409a7dfb63aaf3
Reviewed-on: https://chromium-review.googlesource.com/836617
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Shawn N <shawnn@chromium.org>

3 files changed, 343 insertions, 1 deletions

diff --git a/chip/stm32/build.mk b/chip/stm32/build.mk
index a5249b4b4a..ff069c9fa6 100644
--- a/chip/stm32/build.mk
+++ b/chip/stm32/build.mk
@@ -31,6 +31,7 @@ endif
 # Select between 16-bit and 32-bit timer for clock source
 TIMER_TYPE=$(if $(CONFIG_STM_HWTIMER32),32,)
 DMA_TYPE=$(if $(CHIP_FAMILY_STM32F4)$(CHIP_FAMILY_STM32H7),-stm32f4,)
+SPI_TYPE=$(if $(CHIP_FAMILY_STM32H7),-stm32h7,)
 
 chip-$(CONFIG_DMA)+=dma$(DMA_TYPE).o
 chip-$(CONFIG_COMMON_RUNTIME)+=system.o
@@ -39,7 +40,7 @@ ifeq ($(CHIP_FAMILY),$(filter $(CHIP_FAMILY),stm32f0 stm32f3 stm32f4))
 chip-y+=clock-f.o
 endif
 chip-$(CONFIG_SPI)+=spi.o
-chip-$(CONFIG_SPI_MASTER)+=spi_master.o
+chip-$(CONFIG_SPI_MASTER)+=spi_master$(SPI_TYPE).o
 chip-$(CONFIG_COMMON_GPIO)+=gpio.o gpio-$(CHIP_FAMILY).o
 chip-$(CONFIG_COMMON_TIMER)+=hwtimer$(TIMER_TYPE).o
 chip-$(CONFIG_I2C)+=i2c-$(CHIP_FAMILY).o
diff --git a/chip/stm32/spi_master-stm32h7.c b/chip/stm32/spi_master-stm32h7.c
new file mode 100644
index 0000000000..af4c3a30f2
--- /dev/null
+++ b/chip/stm32/spi_master-stm32h7.c
@@ -0,0 +1,339 @@
+/*
+ * Copyright 2017 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * SPI master driver.
+ */
+
+#include "common.h"
+#include "dma.h"
+#include "gpio.h"
+#include "shared_mem.h"
+#include "spi.h"
+#include "stm32-dma.h"
+#include "task.h"
+#include "timer.h"
+#include "util.h"
+
+/* SPI ports are used as master */
+static stm32_spi_regs_t *SPI_REGS[] = {
+#ifdef CONFIG_STM32_SPI1_MASTER
+	STM32_SPI1_REGS,
+#endif
+	STM32_SPI2_REGS,
+	STM32_SPI3_REGS,
+	STM32_SPI4_REGS,
+};
+
+/* DMA request mapping on channels */
+static uint8_t dma_req_tx[ARRAY_SIZE(SPI_REGS)] = {
+#ifdef CONFIG_STM32_SPI1_MASTER
+	DMAMUX1_REQ_SPI1_TX,
+#endif
+	DMAMUX1_REQ_SPI2_TX,
+	DMAMUX1_REQ_SPI3_TX,
+	DMAMUX1_REQ_SPI4_TX,
+};
+static uint8_t dma_req_rx[ARRAY_SIZE(SPI_REGS)] = {
+#ifdef CONFIG_STM32_SPI1_MASTER
+	DMAMUX1_REQ_SPI1_RX,
+#endif
+	DMAMUX1_REQ_SPI2_RX,
+	DMAMUX1_REQ_SPI3_RX,
+	DMAMUX1_REQ_SPI4_RX,
+};
+
+static struct mutex spi_mutex[ARRAY_SIZE(SPI_REGS)];
+
+#define SPI_TRANSACTION_TIMEOUT_USEC (800 * MSEC)
+
+static const struct dma_option dma_tx_option[] = {
+#ifdef CONFIG_STM32_SPI1_MASTER
+	{
+		STM32_DMAC_SPI1_TX, (void *)&STM32_SPI1_REGS->txdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+#endif
+	{
+		STM32_DMAC_SPI2_TX, (void *)&STM32_SPI2_REGS->txdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+	{
+		STM32_DMAC_SPI3_TX, (void *)&STM32_SPI3_REGS->txdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+	{
+		STM32_DMAC_SPI4_TX, (void *)&STM32_SPI4_REGS->txdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+};
+
+static const struct dma_option dma_rx_option[] = {
+#ifdef CONFIG_STM32_SPI1_MASTER
+	{
+		STM32_DMAC_SPI1_RX, (void *)&STM32_SPI1_REGS->rxdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+#endif
+	{
+		STM32_DMAC_SPI2_RX, (void *)&STM32_SPI2_REGS->rxdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+	{
+		STM32_DMAC_SPI3_RX, (void *)&STM32_SPI3_REGS->rxdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+	{
+		STM32_DMAC_SPI4_RX, (void *)&STM32_SPI4_REGS->rxdr,
+		STM32_DMA_CCR_MSIZE_8_BIT | STM32_DMA_CCR_PSIZE_8_BIT
+	},
+};
+
+static uint8_t spi_enabled[ARRAY_SIZE(SPI_REGS)];
+
+/**
+ * Initialize SPI module, registers, and clocks
+ *
+ * - port: which port to initialize.
+ */
+static void spi_master_config(int port)
+{
+	int i, div = 0;
+
+	stm32_spi_regs_t *spi = SPI_REGS[port];
+
+	/*
+	 * Set SPI master, baud rate, and software slave control.
+	 */
+	for (i = 0; i < spi_devices_used; i++)
+		if ((spi_devices[i].port == port) &&
+		    (div < spi_devices[i].div))
+			div = spi_devices[i].div;
+
+	spi->cr1 = STM32_SPI_CR1_SSI;
+	spi->cfg2 = STM32_SPI_CFG2_MSTR | STM32_SPI_CFG2_SSM
+			| STM32_SPI_CFG2_AFCNTR;
+	spi->cfg1 = STM32_SPI_CFG1_DATASIZE(8) | STM32_SPI_CFG1_FTHLV(4)
+			| STM32_SPI_CFG1_CRCSIZE(8) | STM32_SPI_CR1_DIV(div);
+
+	dma_select_channel(dma_tx_option[port].channel, dma_req_tx[port]);
+	dma_select_channel(dma_rx_option[port].channel, dma_req_rx[port]);
+}
+
+static int spi_master_initialize(int port)
+{
+	int i;
+
+	spi_master_config(port);
+
+	for (i = 0; i < spi_devices_used; i++) {
+		if (spi_devices[i].port != port)
+			continue;
+		/* Drive SS high */
+		gpio_set_level(spi_devices[i].gpio_cs, 1);
+	}
+
+	/* Set flag */
+	spi_enabled[port] = 1;
+
+	return EC_SUCCESS;
+}
+
+/**
+ * Shutdown SPI module
+ */
+static int spi_master_shutdown(int port)
+{
+	int rv = EC_SUCCESS;
+	stm32_spi_regs_t *spi = SPI_REGS[port];
+
+	/* Set flag */
+	spi_enabled[port] = 0;
+
+	/* Disable DMA streams */
+	dma_disable(dma_tx_option[port].channel);
+	dma_disable(dma_rx_option[port].channel);
+
+	/* Disable SPI */
+	spi->cr1 &= ~STM32_SPI_CR1_SPE;
+
+	/* Disable DMA buffers */
+	spi->cfg1 &= ~(STM32_SPI_CFG1_TXDMAEN | STM32_SPI_CFG1_RXDMAEN);
+
+	return rv;
+}
+
+int spi_enable(int port, int enable)
+{
+	if (enable == spi_enabled[port])
+		return EC_SUCCESS;
+	if (enable)
+		return spi_master_initialize(port);
+	else
+		return spi_master_shutdown(port);
+}
+
+static int spi_dma_start(int port, const uint8_t *txdata,
+		uint8_t *rxdata, int len)
+{
+	dma_chan_t *txdma;
+	stm32_spi_regs_t *spi = SPI_REGS[port];
+
+	/*
+	 * Workaround for STM32H7 errata: without resetting the SPI controller,
+	 * the RX DMA requests will happen too early on the 2nd transfer.
+	 */
+	STM32_RCC_APB2RSTR = STM32_RCC_PB2_SPI4;
+	STM32_RCC_APB2RSTR = 0;
+	dma_clear_isr(dma_tx_option[port].channel);
+	dma_clear_isr(dma_rx_option[port].channel);
+	/* restore proper SPI configuration registers. */
+	spi_master_config(port);
+
+	spi->cr2 = len;
+	spi->cfg1 |= STM32_SPI_CFG1_RXDMAEN;
+	/* Set up RX DMA */
+	if (rxdata)
+		dma_start_rx(&dma_rx_option[port], len, rxdata);
+
+	/* Set up TX DMA */
+	if (txdata) {
+		txdma = dma_get_channel(dma_tx_option[port].channel);
+		dma_prepare_tx(&dma_tx_option[port], len, txdata);
+		dma_go(txdma);
+	}
+
+	spi->cfg1 |= STM32_SPI_CFG1_TXDMAEN;
+	spi->cr1 |= STM32_SPI_CR1_SPE;
+	spi->cr1 |= STM32_SPI_CR1_CSTART;
+
+	return EC_SUCCESS;
+}
+
+static inline int dma_is_enabled(const struct dma_option *option)
+{
+	/* dma_bytes_done() returns 0 if channel is not enabled */
+	return dma_bytes_done(dma_get_channel(option->channel), -1);
+}
+
+static int spi_dma_wait(int port)
+{
+	timestamp_t timeout;
+	stm32_spi_regs_t *spi = SPI_REGS[port];
+	int rv = EC_SUCCESS;
+
+	/* Wait for DMA transmission to complete */
+	if (dma_is_enabled(&dma_tx_option[port])) {
+		rv = dma_wait(dma_tx_option[port].channel);
+		if (rv)
+			return rv;
+
+		timeout.val = get_time().val + SPI_TRANSACTION_TIMEOUT_USEC;
+		/* Wait for FIFO empty and BSY bit clear */
+		while (!(spi->sr & (STM32_SPI_SR_TXC)))
+			if (get_time().val > timeout.val)
+				return EC_ERROR_TIMEOUT;
+
+		/* Disable TX DMA */
+		dma_disable(dma_tx_option[port].channel);
+	}
+
+	/* Wait for DMA reception to complete */
+	if (dma_is_enabled(&dma_rx_option[port])) {
+		rv = dma_wait(dma_rx_option[port].channel);
+		if (rv)
+			return rv;
+
+		timeout.val = get_time().val + SPI_TRANSACTION_TIMEOUT_USEC;
+		/* Wait for FRLVL[1:0] to indicate FIFO empty */
+		while (spi->sr & (STM32_SPI_SR_FRLVL | STM32_SPI_SR_RXNE))
+			if (get_time().val > timeout.val)
+				return EC_ERROR_TIMEOUT;
+
+		/* Disable RX DMA */
+		dma_disable(dma_rx_option[port].channel);
+	}
+
+	spi->cr1 &= ~STM32_SPI_CR1_SPE;
+	spi->cfg1 &= ~(STM32_SPI_CFG1_TXDMAEN | STM32_SPI_CFG1_RXDMAEN);
+
+	return rv;
+}
+
+int spi_transaction_async(const struct spi_device_t *spi_device,
+			  const uint8_t *txdata, int txlen,
+			  uint8_t *rxdata, int rxlen)
+{
+	int rv = EC_SUCCESS;
+	int port = spi_device->port;
+	int full_readback = 0;
+
+	char *buf = NULL;
+
+#ifndef CONFIG_SPI_HALFDUPLEX
+	if (rxlen == SPI_READBACK_ALL) {
+		buf = rxdata;
+		full_readback = 1;
+	} else {
+		rv = shared_mem_acquire(MAX(txlen, rxlen), &buf);
+		if (rv != EC_SUCCESS)
+			return rv;
+	}
+#endif
+
+	/* Drive SS low */
+	gpio_set_level(spi_device->gpio_cs, 0);
+
+	rv = spi_dma_start(port, txdata, buf, txlen);
+	if (rv != EC_SUCCESS)
+		goto err_free;
+
+	if (full_readback)
+		return EC_SUCCESS;
+
+	if (rxlen) {
+		rv = spi_dma_wait(port);
+		if (rv != EC_SUCCESS)
+			goto err_free;
+
+		rv = spi_dma_start(port, buf, rxdata, rxlen);
+		if (rv != EC_SUCCESS)
+			goto err_free;
+	}
+
+err_free:
+	if (!full_readback)
+		shared_mem_release(buf);
+	return rv;
+}
+
+int spi_transaction_flush(const struct spi_device_t *spi_device)
+{
+	int rv = spi_dma_wait(spi_device->port);
+
+	/* Drive SS high */
+	gpio_set_level(spi_device->gpio_cs, 1);
+
+	return rv;
+}
+
+int spi_transaction_wait(const struct spi_device_t *spi_device)
+{
+	return spi_dma_wait(spi_device->port);
+}
+
+int spi_transaction(const struct spi_device_t *spi_device,
+		    const uint8_t *txdata, int txlen,
+		    uint8_t *rxdata, int rxlen)
+{
+	int rv;
+	int port = spi_device->port;
+
+	mutex_lock(spi_mutex + port);
+	rv = spi_transaction_async(spi_device, txdata, txlen, rxdata, rxlen);
+	rv |= spi_transaction_flush(spi_device);
+	mutex_unlock(spi_mutex + port);
+
+	return rv;
+}
diff --git a/include/spi.h b/include/spi.h
index 49bddd3cc3..5cf3389e91 100644
--- a/include/spi.h
+++ b/include/spi.h
@@ -88,6 +88,8 @@ int spi_transaction(const struct spi_device_t *spi_device,
 /* Similar to spi_transaction(), but hands over to DMA for reading response.
  * Must call spi_transaction_flush() after this to make sure the response is
  * received.
+ * Contrary the regular spi_transaction(), this function does NOT lock the
+ * SPI port, it's up to the caller to ensure proper mutual exclusion if needed.
  */
 int spi_transaction_async(const struct spi_device_t *spi_device,
 			  const uint8_t *txdata, int txlen,