drivers/serial/serial_msm.c - filogic/uboot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Qualcomm UART driver
  *
  * (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
  *
  * UART will work in Data Mover mode.
  * Based on Linux driver.
  */

 #include <common.h>
 #include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <malloc.h>
 #include <serial.h>
 #include <watchdog.h>
 #include <asm/global_data.h>
 #include <asm/io.h>
 #include <linux/compiler.h>
 #include <linux/delay.h>
 #include <dm/pinctrl.h>

 /* Serial registers - this driver works in uartdm mode*/

 #define UARTDM_DMRX             0x34 /* Max RX transfer length */
 #define UARTDM_DMEN             0x3C /* DMA/data-packing mode */
 #define UARTDM_NCF_TX           0x40 /* Number of chars to TX */

 #define UARTDM_RXFS             0x50 /* RX channel status register */
 #define UARTDM_RXFS_BUF_SHIFT   0x7  /* Number of bytes in the packing buffer */
 #define UARTDM_RXFS_BUF_MASK    0x7
 #define UARTDM_MR1				 0x00
 #define UARTDM_MR2				 0x04
 /*
  * This is documented on page 1817 of the apq8016e technical reference manual.
  * section 6.2.5.3.26
  *
  * The upper nybble contains the bit clock divider for the RX pin, the lower
  * nybble defines the TX pin. In almost all cases these should be the same value.
  *
  * The baud rate is the core clock frequency divided by the fixed divider value
  * programmed into this register (defined in calc_csr_bitrate()).
  */
 #define UARTDM_CSR				 0xA0

 #define UARTDM_SR                0xA4 /* Status register */
 #define UARTDM_SR_RX_READY       (1 << 0) /* Word is the receiver FIFO */
 #define UARTDM_SR_TX_EMPTY       (1 << 3) /* Transmitter underrun */
 #define UARTDM_SR_UART_OVERRUN   (1 << 4) /* Receive overrun */

 #define UARTDM_CR                         0xA8 /* Command register */
 #define UARTDM_CR_CMD_RESET_ERR           (3 << 4) /* Clear overrun error */
 #define UARTDM_CR_CMD_RESET_STALE_INT     (8 << 4) /* Clears stale irq */
 #define UARTDM_CR_CMD_RESET_TX_READY      (3 << 8) /* Clears TX Ready irq*/
 #define UARTDM_CR_CMD_FORCE_STALE         (4 << 8) /* Causes stale event */
 #define UARTDM_CR_CMD_STALE_EVENT_DISABLE (6 << 8) /* Disable stale event */

 #define UARTDM_IMR                0xB0 /* Interrupt mask register */
 #define UARTDM_ISR                0xB4 /* Interrupt status register */
 #define UARTDM_ISR_TX_READY       0x80 /* TX FIFO empty */

 #define UARTDM_TF               0x100 /* UART Transmit FIFO register */
 #define UARTDM_RF               0x140 /* UART Receive FIFO register */

 #define MSM_BOOT_UART_DM_8_N_1_MODE	0x34
 #define MSM_BOOT_UART_DM_CMD_RESET_RX	0x10
 #define MSM_BOOT_UART_DM_CMD_RESET_TX	0x20
 #define MSM_UART_MR1_RX_RDY_CTL		BIT(7)

 DECLARE_GLOBAL_DATA_PTR;

 struct msm_serial_data {
 	phys_addr_t base;
 	unsigned chars_cnt; /* number of buffered chars */
 	uint32_t chars_buf; /* buffered chars */
 	uint32_t clk_rate; /* core clock rate */
 };

 static int msm_serial_fetch(struct udevice *dev)
 {
 	struct msm_serial_data *priv = dev_get_priv(dev);
 	unsigned sr;

 	if (priv->chars_cnt)
 		return priv->chars_cnt;

 	/* Clear error in case of buffer overrun */
 	if (readl(priv->base + UARTDM_SR) & UARTDM_SR_UART_OVERRUN)
 		writel(UARTDM_CR_CMD_RESET_ERR, priv->base + UARTDM_CR);

 	/* We need to fetch new character */
 	sr = readl(priv->base + UARTDM_SR);

 	if (sr & UARTDM_SR_RX_READY) {
 		/* There are at least 4 bytes in fifo */
 		priv->chars_buf = readl(priv->base + UARTDM_RF);
 		priv->chars_cnt = 4;
 	} else {
 		/* Check if there is anything in fifo */
 		priv->chars_cnt = readl(priv->base + UARTDM_RXFS);
 		/* Extract number of characters in UART packing buffer*/
 		priv->chars_cnt = (priv->chars_cnt >>
 				   UARTDM_RXFS_BUF_SHIFT) &
 				  UARTDM_RXFS_BUF_MASK;
 		if (!priv->chars_cnt)
 			return 0;

 		/* There is at least one charcter, move it to fifo */
 		writel(UARTDM_CR_CMD_FORCE_STALE,
 		       priv->base + UARTDM_CR);

 		priv->chars_buf = readl(priv->base + UARTDM_RF);
 		writel(UARTDM_CR_CMD_RESET_STALE_INT,
 		       priv->base + UARTDM_CR);
 		writel(0x7, priv->base + UARTDM_DMRX);
 	}

 	return priv->chars_cnt;
 }

 static int msm_serial_getc(struct udevice *dev)
 {
 	struct msm_serial_data *priv = dev_get_priv(dev);
 	char c;

 	if (!msm_serial_fetch(dev))
 		return -EAGAIN;

 	c = priv->chars_buf & 0xFF;
 	priv->chars_buf >>= 8;
 	priv->chars_cnt--;

 	return c;
 }

 static int msm_serial_putc(struct udevice *dev, const char ch)
 {
 	struct msm_serial_data *priv = dev_get_priv(dev);

 	if (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) &&
 	    !(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY))
 		return -EAGAIN;

 	writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR);

 	writel(1, priv->base + UARTDM_NCF_TX);
 	writel(ch, priv->base + UARTDM_TF);

 	return 0;
 }

 static int msm_serial_pending(struct udevice *dev, bool input)
 {
 	if (input) {
 		if (msm_serial_fetch(dev))
 			return 1;
 	}

 	return 0;
 }

 static const struct dm_serial_ops msm_serial_ops = {
 	.putc = msm_serial_putc,
 	.pending = msm_serial_pending,
 	.getc = msm_serial_getc,
 };

 static long msm_uart_clk_init(struct udevice *dev)
 {
 	struct msm_serial_data *priv = dev_get_priv(dev);
 	struct clk clk;
 	int ret;
 	long rate;

 	ret = clk_get_by_name(dev, "core", &clk);
 	if (ret < 0) {
 		pr_warn("%s: Failed to get clock: %d\n", __func__, ret);
 		return 0;
 	}

 	rate = clk_set_rate(&clk, priv->clk_rate);

 	return rate;
 }

 static int calc_csr_bitrate(struct msm_serial_data *priv)
 {
 	/* This table is from the TRE. See the definition of UARTDM_CSR */
 	unsigned int csr_div_table[] = {24576, 12288, 6144, 3072, 1536, 768, 512, 384,
 					256,   192,   128,  96,   64,   48,  32,  16};
 	int i = ARRAY_SIZE(csr_div_table) - 1;
 	/* Currently we only support one baudrate */
 	int baud = 115200;

 	for (; i >= 0; i--) {
 		int x = priv->clk_rate / csr_div_table[i];

 		if (x == baud)
 			/* Duplicate the configuration for RX
 			 * as the lower nybble only configures TX
 			 */
 			return i + (i << 4);
 	}

 	return -EINVAL;
 }

 static void uart_dm_init(struct msm_serial_data *priv)
 {
 	/* Delay initialization for a bit to let pins stabilize if necessary */
 	mdelay(5);
 	int bitrate = calc_csr_bitrate(priv);
 	if (bitrate < 0) {
 		log_warning("Couldn't calculate bit clock divider! Using default\n");
 		/* This happens to be the value used on MSM8916 for the hardcoded clockrate
 		 * in clock-apq8016. It's at least a better guess than a value we *know*
 		 * is wrong...
 		 */
 		bitrate = 0xCC;
 	}

 	writel(bitrate, priv->base + UARTDM_CSR);
 	/* Enable RS232 flow control to support RS232 db9 connector */
 	writel(MSM_UART_MR1_RX_RDY_CTL, priv->base + UARTDM_MR1);
 	writel(MSM_BOOT_UART_DM_8_N_1_MODE, priv->base + UARTDM_MR2);
 	writel(MSM_BOOT_UART_DM_CMD_RESET_RX, priv->base + UARTDM_CR);
 	writel(MSM_BOOT_UART_DM_CMD_RESET_TX, priv->base + UARTDM_CR);

 	/* Make sure BAM/single character mode is disabled */
 	writel(0x0, priv->base + UARTDM_DMEN);
 }
 static int msm_serial_probe(struct udevice *dev)
 {
 	struct msm_serial_data *priv = dev_get_priv(dev);
 	long rate;

 	/* No need to reinitialize the UART after relocation */
 	if (gd->flags & GD_FLG_RELOC)
 		return 0;

 	rate = msm_uart_clk_init(dev);
 	if (rate < 0)
 		return rate;
 	if (!rate) {
 		log_err("Got core clock rate of 0... Please fix your clock driver\n");
 		return -EINVAL;
 	}

 	/* Update the clock rate to the actual programmed rate returned by the
 	 * clock driver
 	 */
 	priv->clk_rate = rate;

 	uart_dm_init(priv);

 	return 0;
 }

 static int msm_serial_of_to_plat(struct udevice *dev)
 {
 	struct msm_serial_data *priv = dev_get_priv(dev);
 	int ret;

 	priv->base = dev_read_addr(dev);
 	if (priv->base == FDT_ADDR_T_NONE)
 		return -EINVAL;

 	ret = dev_read_u32(dev, "clock-frequency", &priv->clk_rate);
 	if (ret < 0) {
 		log_debug("No clock frequency specified, using default rate\n");
 		/* Default for APQ8016 */
 		priv->clk_rate = 7372800;
 	}

 	return 0;
 }

 static const struct udevice_id msm_serial_ids[] = {
 	{ .compatible = "qcom,msm-uartdm-v1.4" },
 	{ }
 };

 U_BOOT_DRIVER(serial_msm) = {
 	.name	= "serial_msm",
 	.id	= UCLASS_SERIAL,
 	.of_match = msm_serial_ids,
 	.of_to_plat = msm_serial_of_to_plat,
 	.priv_auto	= sizeof(struct msm_serial_data),
 	.probe = msm_serial_probe,
 	.ops	= &msm_serial_ops,
 	.flags = DM_FLAG_PRE_RELOC,
 };

 #ifdef CONFIG_DEBUG_UART_MSM

 static struct msm_serial_data init_serial_data = {
 	.base = CONFIG_VAL(DEBUG_UART_BASE),
 	.clk_rate = CONFIG_VAL(DEBUG_UART_CLOCK),
 };

 #include <debug_uart.h>

 /* Uncomment to turn on UART clocks when debugging U-Boot as aboot on MSM8916 */
 //int apq8016_clk_init_uart(phys_addr_t gcc_base, unsigned long id);

 static inline void _debug_uart_init(void)
 {
 	/*
 	 * Uncomment to turn on UART clocks when debugging U-Boot as aboot
 	 * on MSM8916. Supported debug UART clock IDs:
 	 *   - db410c: GCC_BLSP1_UART2_APPS_CLK
 	 *   - HMIBSC: GCC_BLSP1_UART1_APPS_CLK
 	 */
 	//apq8016_clk_init_uart(0x1800000, <uart_clk_id>);
 	uart_dm_init(&init_serial_data);
 }

 static inline void _debug_uart_putc(int ch)
 {
 	struct msm_serial_data *priv = &init_serial_data;

 	while (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) &&
 	       !(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY))
 		;

 	writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR);

 	writel(1, priv->base + UARTDM_NCF_TX);
 	writel(ch, priv->base + UARTDM_TF);
 }

 DEBUG_UART_FUNCS

 #endif
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Qualcomm UART driver
	*
	* (C) Copyright 2015 Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
	*
	* UART will work in Data Mover mode.
	* Based on Linux driver.
	*/

	#include <common.h>
	#include <clk.h>
	#include <dm.h>
	#include <errno.h>
	#include <malloc.h>
	#include <serial.h>
	#include <watchdog.h>
	#include <asm/global_data.h>
	#include <asm/io.h>
	#include <linux/compiler.h>
	#include <linux/delay.h>
	#include <dm/pinctrl.h>

	/* Serial registers - this driver works in uartdm mode*/

	#define UARTDM_DMRX 0x34 /* Max RX transfer length */
	#define UARTDM_DMEN 0x3C /* DMA/data-packing mode */
	#define UARTDM_NCF_TX 0x40 /* Number of chars to TX */

	#define UARTDM_RXFS 0x50 /* RX channel status register */
	#define UARTDM_RXFS_BUF_SHIFT 0x7 /* Number of bytes in the packing buffer */
	#define UARTDM_RXFS_BUF_MASK 0x7
	#define UARTDM_MR1 0x00
	#define UARTDM_MR2 0x04
	/*
	* This is documented on page 1817 of the apq8016e technical reference manual.
	* section 6.2.5.3.26
	*
	* The upper nybble contains the bit clock divider for the RX pin, the lower
	* nybble defines the TX pin. In almost all cases these should be the same value.
	*
	* The baud rate is the core clock frequency divided by the fixed divider value
	* programmed into this register (defined in calc_csr_bitrate()).
	*/
	#define UARTDM_CSR 0xA0

	#define UARTDM_SR 0xA4 /* Status register */
	#define UARTDM_SR_RX_READY (1 << 0) /* Word is the receiver FIFO */
	#define UARTDM_SR_TX_EMPTY (1 << 3) /* Transmitter underrun */
	#define UARTDM_SR_UART_OVERRUN (1 << 4) /* Receive overrun */

	#define UARTDM_CR 0xA8 /* Command register */
	#define UARTDM_CR_CMD_RESET_ERR (3 << 4) /* Clear overrun error */
	#define UARTDM_CR_CMD_RESET_STALE_INT (8 << 4) /* Clears stale irq */
	#define UARTDM_CR_CMD_RESET_TX_READY (3 << 8) /* Clears TX Ready irq*/
	#define UARTDM_CR_CMD_FORCE_STALE (4 << 8) /* Causes stale event */
	#define UARTDM_CR_CMD_STALE_EVENT_DISABLE (6 << 8) /* Disable stale event */

	#define UARTDM_IMR 0xB0 /* Interrupt mask register */
	#define UARTDM_ISR 0xB4 /* Interrupt status register */
	#define UARTDM_ISR_TX_READY 0x80 /* TX FIFO empty */

	#define UARTDM_TF 0x100 /* UART Transmit FIFO register */
	#define UARTDM_RF 0x140 /* UART Receive FIFO register */

	#define MSM_BOOT_UART_DM_8_N_1_MODE 0x34
	#define MSM_BOOT_UART_DM_CMD_RESET_RX 0x10
	#define MSM_BOOT_UART_DM_CMD_RESET_TX 0x20
	#define MSM_UART_MR1_RX_RDY_CTL BIT(7)

	DECLARE_GLOBAL_DATA_PTR;

	struct msm_serial_data {
	phys_addr_t base;
	unsigned chars_cnt; /* number of buffered chars */
	uint32_t chars_buf; /* buffered chars */
	uint32_t clk_rate; /* core clock rate */
	};

	static int msm_serial_fetch(struct udevice *dev)
	{
	struct msm_serial_data *priv = dev_get_priv(dev);
	unsigned sr;

	if (priv->chars_cnt)
	return priv->chars_cnt;

	/* Clear error in case of buffer overrun */
	if (readl(priv->base + UARTDM_SR) & UARTDM_SR_UART_OVERRUN)
	writel(UARTDM_CR_CMD_RESET_ERR, priv->base + UARTDM_CR);

	/* We need to fetch new character */
	sr = readl(priv->base + UARTDM_SR);

	if (sr & UARTDM_SR_RX_READY) {
	/* There are at least 4 bytes in fifo */
	priv->chars_buf = readl(priv->base + UARTDM_RF);
	priv->chars_cnt = 4;
	} else {
	/* Check if there is anything in fifo */
	priv->chars_cnt = readl(priv->base + UARTDM_RXFS);
	/* Extract number of characters in UART packing buffer*/
	priv->chars_cnt = (priv->chars_cnt >>
	UARTDM_RXFS_BUF_SHIFT) &
	UARTDM_RXFS_BUF_MASK;
	if (!priv->chars_cnt)
	return 0;

	/* There is at least one charcter, move it to fifo */
	writel(UARTDM_CR_CMD_FORCE_STALE,
	priv->base + UARTDM_CR);

	priv->chars_buf = readl(priv->base + UARTDM_RF);
	writel(UARTDM_CR_CMD_RESET_STALE_INT,
	priv->base + UARTDM_CR);
	writel(0x7, priv->base + UARTDM_DMRX);
	}

	return priv->chars_cnt;
	}

	static int msm_serial_getc(struct udevice *dev)
	{
	struct msm_serial_data *priv = dev_get_priv(dev);
	char c;

	if (!msm_serial_fetch(dev))
	return -EAGAIN;

	c = priv->chars_buf & 0xFF;
	priv->chars_buf >>= 8;
	priv->chars_cnt--;

	return c;
	}

	static int msm_serial_putc(struct udevice *dev, const char ch)
	{
	struct msm_serial_data *priv = dev_get_priv(dev);

	if (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) &&
	!(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY))
	return -EAGAIN;

	writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR);

	writel(1, priv->base + UARTDM_NCF_TX);
	writel(ch, priv->base + UARTDM_TF);

	return 0;
	}

	static int msm_serial_pending(struct udevice *dev, bool input)
	{
	if (input) {
	if (msm_serial_fetch(dev))
	return 1;
	}

	return 0;
	}

	static const struct dm_serial_ops msm_serial_ops = {
	.putc = msm_serial_putc,
	.pending = msm_serial_pending,
	.getc = msm_serial_getc,
	};

	static long msm_uart_clk_init(struct udevice *dev)
	{
	struct msm_serial_data *priv = dev_get_priv(dev);
	struct clk clk;
	int ret;
	long rate;

	ret = clk_get_by_name(dev, "core", &clk);
	if (ret < 0) {
	pr_warn("%s: Failed to get clock: %d\n", __func__, ret);
	return 0;
	}

	rate = clk_set_rate(&clk, priv->clk_rate);

	return rate;
	}

	static int calc_csr_bitrate(struct msm_serial_data *priv)
	{
	/* This table is from the TRE. See the definition of UARTDM_CSR */
	unsigned int csr_div_table[] = {24576, 12288, 6144, 3072, 1536, 768, 512, 384,
	256, 192, 128, 96, 64, 48, 32, 16};
	int i = ARRAY_SIZE(csr_div_table) - 1;
	/* Currently we only support one baudrate */
	int baud = 115200;

	for (; i >= 0; i--) {
	int x = priv->clk_rate / csr_div_table[i];

	if (x == baud)
	/* Duplicate the configuration for RX
	* as the lower nybble only configures TX
	*/
	return i + (i << 4);
	}

	return -EINVAL;
	}

	static void uart_dm_init(struct msm_serial_data *priv)
	{
	/* Delay initialization for a bit to let pins stabilize if necessary */
	mdelay(5);
	int bitrate = calc_csr_bitrate(priv);
	if (bitrate < 0) {
	log_warning("Couldn't calculate bit clock divider! Using default\n");
	/* This happens to be the value used on MSM8916 for the hardcoded clockrate
	* in clock-apq8016. It's at least a better guess than a value we know
	* is wrong...
	*/
	bitrate = 0xCC;
	}

	writel(bitrate, priv->base + UARTDM_CSR);
	/* Enable RS232 flow control to support RS232 db9 connector */
	writel(MSM_UART_MR1_RX_RDY_CTL, priv->base + UARTDM_MR1);
	writel(MSM_BOOT_UART_DM_8_N_1_MODE, priv->base + UARTDM_MR2);
	writel(MSM_BOOT_UART_DM_CMD_RESET_RX, priv->base + UARTDM_CR);
	writel(MSM_BOOT_UART_DM_CMD_RESET_TX, priv->base + UARTDM_CR);

	/* Make sure BAM/single character mode is disabled */
	writel(0x0, priv->base + UARTDM_DMEN);
	}
	static int msm_serial_probe(struct udevice *dev)
	{
	struct msm_serial_data *priv = dev_get_priv(dev);
	long rate;

	/* No need to reinitialize the UART after relocation */
	if (gd->flags & GD_FLG_RELOC)
	return 0;

	rate = msm_uart_clk_init(dev);
	if (rate < 0)
	return rate;
	if (!rate) {
	log_err("Got core clock rate of 0... Please fix your clock driver\n");
	return -EINVAL;
	}

	/* Update the clock rate to the actual programmed rate returned by the
	* clock driver
	*/
	priv->clk_rate = rate;

	uart_dm_init(priv);

	return 0;
	}

	static int msm_serial_of_to_plat(struct udevice *dev)
	{
	struct msm_serial_data *priv = dev_get_priv(dev);
	int ret;

	priv->base = dev_read_addr(dev);
	if (priv->base == FDT_ADDR_T_NONE)
	return -EINVAL;

	ret = dev_read_u32(dev, "clock-frequency", &priv->clk_rate);
	if (ret < 0) {
	log_debug("No clock frequency specified, using default rate\n");
	/* Default for APQ8016 */
	priv->clk_rate = 7372800;
	}

	return 0;
	}

	static const struct udevice_id msm_serial_ids[] = {
	{ .compatible = "qcom,msm-uartdm-v1.4" },
	{ }
	};

	U_BOOT_DRIVER(serial_msm) = {
	.name = "serial_msm",
	.id = UCLASS_SERIAL,
	.of_match = msm_serial_ids,
	.of_to_plat = msm_serial_of_to_plat,
	.priv_auto = sizeof(struct msm_serial_data),
	.probe = msm_serial_probe,
	.ops = &msm_serial_ops,
	.flags = DM_FLAG_PRE_RELOC,
	};

	#ifdef CONFIG_DEBUG_UART_MSM

	static struct msm_serial_data init_serial_data = {
	.base = CONFIG_VAL(DEBUG_UART_BASE),
	.clk_rate = CONFIG_VAL(DEBUG_UART_CLOCK),
	};

	#include <debug_uart.h>

	/* Uncomment to turn on UART clocks when debugging U-Boot as aboot on MSM8916 */
	//int apq8016_clk_init_uart(phys_addr_t gcc_base, unsigned long id);

	static inline void _debug_uart_init(void)
	{
	/*
	* Uncomment to turn on UART clocks when debugging U-Boot as aboot
	* on MSM8916. Supported debug UART clock IDs:
	* - db410c: GCC_BLSP1_UART2_APPS_CLK
	* - HMIBSC: GCC_BLSP1_UART1_APPS_CLK
	*/
	//apq8016_clk_init_uart(0x1800000, <uart_clk_id>);
	uart_dm_init(&init_serial_data);
	}

	static inline void _debug_uart_putc(int ch)
	{
	struct msm_serial_data *priv = &init_serial_data;

	while (!(readl(priv->base + UARTDM_SR) & UARTDM_SR_TX_EMPTY) &&
	!(readl(priv->base + UARTDM_ISR) & UARTDM_ISR_TX_READY))
	;

	writel(UARTDM_CR_CMD_RESET_TX_READY, priv->base + UARTDM_CR);

	writel(1, priv->base + UARTDM_NCF_TX);
	writel(ch, priv->base + UARTDM_TF);
	}

	DEBUG_UART_FUNCS

	#endif