[PATCH v3 00/13] serial: qcom-geni-serial: implement support for SE DMA

[PATCH v3 00/13] serial: qcom-geni-serial: implement support for SE DMA

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The goal of this series is to update the qcom-geni-serial driver to use
the DMA mode of the QUPv3 serial engine. This is accomplished by the last
patch in the series. The previous ones contain either various tweaks,
reworks and refactoring or prepare the driver for adding DMA support.

More work will follow on the serial engine in order to reduce code
redundancy among its users and add support for SE DMA to the qcom GENI
SPI driver.

v2 -> v3:
- drop devres patches from the series

v1 -> v2:
- turn to_dev_uport() macro into a static inline function
- use CIRC_CNT_TO_END() and uart_xmit_advance() where applicable and don't
  handle xmit->tail directly
- drop sizeof() where BYTES_PER_FIFO_WORD can be used
- further refactor qcom_geni_serial_handle_tx_fifo()
- collect review tags

Bartosz Golaszewski (13):
  tty: serial: qcom-geni-serial: drop unneeded forward definitions
  tty: serial: qcom-geni-serial: remove unused symbols
  tty: serial: qcom-geni-serial: align #define values
  tty: serial: qcom-geni-serial: improve the to_dev_port() macro
  tty: serial: qcom-geni-serial: remove stray newlines
  tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()
  tty: serial: qcom-geni-serial: remove unneeded tabs
  tty: serial: qcom-geni-serial: refactor qcom_geni_serial_handle_tx()
  tty: serial: qcom-geni-serial: drop the return value from handle_rx
  tty: serial: qcom-geni-serial: use of_device_id data
  tty: serial: qcom-geni-serial: stop operations in progress at shutdown
  soc: qcom-geni-se: add more symbol definitions
  tty: serial: qcom-geni-serial: add support for serial engine DMA

 drivers/tty/serial/qcom_geni_serial.c | 606 +++++++++++++++++---------
 include/linux/qcom-geni-se.h          |   3 +
 2 files changed, 409 insertions(+), 200 deletions(-)

-- 
2.37.2

[PATCH v3 01/13] tty: serial: qcom-geni-serial: drop unneeded forward definitions

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

If we shuffle the code a bit, we can drop all forward definitions of
various static functions.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 79 +++++++++++++--------------
 1 file changed, 37 insertions(+), 42 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 83b66b73303a..9f2212e7b5ec 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -147,11 +147,6 @@ static const struct uart_ops qcom_geni_console_pops;
 static const struct uart_ops qcom_geni_uart_pops;
 static struct uart_driver qcom_geni_console_driver;
 static struct uart_driver qcom_geni_uart_driver;
-static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop);
-static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop);
-static unsigned int qcom_geni_serial_tx_empty(struct uart_port *port);
-static void qcom_geni_serial_stop_rx(struct uart_port *uport);
-static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop);
 
 #define to_dev_port(ptr, member) \
 		container_of(ptr, struct qcom_geni_serial_port, member)
@@ -590,6 +585,11 @@ static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
 	return ret;
 }
 
+static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
+{
+	return !readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
+}
+
 static void qcom_geni_serial_start_tx(struct uart_port *uport)
 {
 	u32 irq_en;
@@ -635,25 +635,29 @@ static void qcom_geni_serial_stop_tx(struct uart_port *uport)
 	writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
 }
 
-static void qcom_geni_serial_start_rx(struct uart_port *uport)
+static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
 {
-	u32 irq_en;
 	u32 status;
+	u32 word_cnt;
+	u32 last_word_byte_cnt;
+	u32 last_word_partial;
+	u32 total_bytes;
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 
-	status = readl(uport->membase + SE_GENI_STATUS);
-	if (status & S_GENI_CMD_ACTIVE)
-		qcom_geni_serial_stop_rx(uport);
-
-	geni_se_setup_s_cmd(&port->se, UART_START_READ, 0);
-
-	irq_en = readl(uport->membase + SE_GENI_S_IRQ_EN);
-	irq_en |= S_RX_FIFO_WATERMARK_EN | S_RX_FIFO_LAST_EN;
-	writel(irq_en, uport->membase + SE_GENI_S_IRQ_EN);
+	status = readl(uport->membase +	SE_GENI_RX_FIFO_STATUS);
+	word_cnt = status & RX_FIFO_WC_MSK;
+	last_word_partial = status & RX_LAST;
+	last_word_byte_cnt = (status & RX_LAST_BYTE_VALID_MSK) >>
+						RX_LAST_BYTE_VALID_SHFT;
 
-	irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
-	irq_en |= M_RX_FIFO_WATERMARK_EN | M_RX_FIFO_LAST_EN;
-	writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
+	if (!word_cnt)
+		return;
+	total_bytes = BYTES_PER_FIFO_WORD * (word_cnt - 1);
+	if (last_word_partial && last_word_byte_cnt)
+		total_bytes += last_word_byte_cnt;
+	else
+		total_bytes += BYTES_PER_FIFO_WORD;
+	port->handle_rx(uport, total_bytes, drop);
 }
 
 static void qcom_geni_serial_stop_rx(struct uart_port *uport)
@@ -694,29 +698,25 @@ static void qcom_geni_serial_stop_rx(struct uart_port *uport)
 		qcom_geni_serial_abort_rx(uport);
 }
 
-static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
+static void qcom_geni_serial_start_rx(struct uart_port *uport)
 {
+	u32 irq_en;
 	u32 status;
-	u32 word_cnt;
-	u32 last_word_byte_cnt;
-	u32 last_word_partial;
-	u32 total_bytes;
 	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
 
-	status = readl(uport->membase +	SE_GENI_RX_FIFO_STATUS);
-	word_cnt = status & RX_FIFO_WC_MSK;
-	last_word_partial = status & RX_LAST;
-	last_word_byte_cnt = (status & RX_LAST_BYTE_VALID_MSK) >>
-						RX_LAST_BYTE_VALID_SHFT;
+	status = readl(uport->membase + SE_GENI_STATUS);
+	if (status & S_GENI_CMD_ACTIVE)
+		qcom_geni_serial_stop_rx(uport);
 
-	if (!word_cnt)
-		return;
-	total_bytes = BYTES_PER_FIFO_WORD * (word_cnt - 1);
-	if (last_word_partial && last_word_byte_cnt)
-		total_bytes += last_word_byte_cnt;
-	else
-		total_bytes += BYTES_PER_FIFO_WORD;
-	port->handle_rx(uport, total_bytes, drop);
+	geni_se_setup_s_cmd(&port->se, UART_START_READ, 0);
+
+	irq_en = readl(uport->membase + SE_GENI_S_IRQ_EN);
+	irq_en |= S_RX_FIFO_WATERMARK_EN | S_RX_FIFO_LAST_EN;
+	writel(irq_en, uport->membase + SE_GENI_S_IRQ_EN);
+
+	irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
+	irq_en |= M_RX_FIFO_WATERMARK_EN | M_RX_FIFO_LAST_EN;
+	writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
 }
 
 static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
@@ -1122,11 +1122,6 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
 	qcom_geni_serial_start_rx(uport);
 }
 
-static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
-{
-	return !readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
-}
-
 #ifdef CONFIG_SERIAL_QCOM_GENI_CONSOLE
 static int qcom_geni_console_setup(struct console *co, char *options)
 {
-- 
2.37.2

[PATCH v3 02/13] tty: serial: qcom-geni-serial: remove unused symbols

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Drop all unused symbols from the driver.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 9f2212e7b5ec..7af5df6833c7 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -42,20 +42,11 @@
 #define UART_TX_PAR_EN		BIT(0)
 #define UART_CTS_MASK		BIT(1)
 
-/* SE_UART_TX_WORD_LEN */
-#define TX_WORD_LEN_MSK		GENMASK(9, 0)
-
 /* SE_UART_TX_STOP_BIT_LEN */
-#define TX_STOP_BIT_LEN_MSK	GENMASK(23, 0)
 #define TX_STOP_BIT_LEN_1	0
-#define TX_STOP_BIT_LEN_1_5	1
 #define TX_STOP_BIT_LEN_2	2
 
-/* SE_UART_TX_TRANS_LEN */
-#define TX_TRANS_LEN_MSK	GENMASK(23, 0)
-
 /* SE_UART_RX_TRANS_CFG */
-#define UART_RX_INS_STATUS_BIT	BIT(2)
 #define UART_RX_PAR_EN		BIT(3)
 
 /* SE_UART_RX_WORD_LEN */
@@ -66,12 +57,9 @@
 
 /* SE_UART_TX_PARITY_CFG/RX_PARITY_CFG */
 #define PAR_CALC_EN		BIT(0)
-#define PAR_MODE_MSK		GENMASK(2, 1)
-#define PAR_MODE_SHFT		1
 #define PAR_EVEN		0x00
 #define PAR_ODD			0x01
 #define PAR_SPACE		0x10
-#define PAR_MARK		0x11
 
 /* SE_UART_MANUAL_RFR register fields */
 #define UART_MANUAL_RFR_EN	BIT(31)
@@ -80,11 +68,8 @@
 
 /* UART M_CMD OP codes */
 #define UART_START_TX		0x1
-#define UART_START_BREAK	0x4
-#define UART_STOP_BREAK		0x5
 /* UART S_CMD OP codes */
 #define UART_START_READ		0x1
-#define UART_PARAM		0x1
 
 #define UART_OVERSAMPLING	32
 #define STALE_TIMEOUT		16
-- 
2.37.2

[PATCH v3 03/13] tty: serial: qcom-geni-serial: align #define values

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Keep the #define symbols aligned for better readability.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 62 +++++++++++++--------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 7af5df6833c7..97ee7c074b79 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -39,57 +39,57 @@
 #define SE_UART_MANUAL_RFR		0x2ac
 
 /* SE_UART_TRANS_CFG */
-#define UART_TX_PAR_EN		BIT(0)
-#define UART_CTS_MASK		BIT(1)
+#define UART_TX_PAR_EN			BIT(0)
+#define UART_CTS_MASK			BIT(1)
 
 /* SE_UART_TX_STOP_BIT_LEN */
-#define TX_STOP_BIT_LEN_1	0
-#define TX_STOP_BIT_LEN_2	2
+#define TX_STOP_BIT_LEN_1		0
+#define TX_STOP_BIT_LEN_2		2
 
 /* SE_UART_RX_TRANS_CFG */
-#define UART_RX_PAR_EN		BIT(3)
+#define UART_RX_PAR_EN			BIT(3)
 
 /* SE_UART_RX_WORD_LEN */
-#define RX_WORD_LEN_MASK	GENMASK(9, 0)
+#define RX_WORD_LEN_MASK		GENMASK(9, 0)
 
 /* SE_UART_RX_STALE_CNT */
-#define RX_STALE_CNT		GENMASK(23, 0)
+#define RX_STALE_CNT			GENMASK(23, 0)
 
 /* SE_UART_TX_PARITY_CFG/RX_PARITY_CFG */
-#define PAR_CALC_EN		BIT(0)
-#define PAR_EVEN		0x00
-#define PAR_ODD			0x01
-#define PAR_SPACE		0x10
+#define PAR_CALC_EN			BIT(0)
+#define PAR_EVEN			0x00
+#define PAR_ODD				0x01
+#define PAR_SPACE			0x10
 
 /* SE_UART_MANUAL_RFR register fields */
-#define UART_MANUAL_RFR_EN	BIT(31)
-#define UART_RFR_NOT_READY	BIT(1)
-#define UART_RFR_READY		BIT(0)
+#define UART_MANUAL_RFR_EN		BIT(31)
+#define UART_RFR_NOT_READY		BIT(1)
+#define UART_RFR_READY			BIT(0)
 
 /* UART M_CMD OP codes */
-#define UART_START_TX		0x1
+#define UART_START_TX			0x1
 /* UART S_CMD OP codes */
-#define UART_START_READ		0x1
-
-#define UART_OVERSAMPLING	32
-#define STALE_TIMEOUT		16
-#define DEFAULT_BITS_PER_CHAR	10
-#define GENI_UART_CONS_PORTS	1
-#define GENI_UART_PORTS		3
-#define DEF_FIFO_DEPTH_WORDS	16
-#define DEF_TX_WM		2
-#define DEF_FIFO_WIDTH_BITS	32
-#define UART_RX_WM		2
+#define UART_START_READ			0x1
+
+#define UART_OVERSAMPLING		32
+#define STALE_TIMEOUT			16
+#define DEFAULT_BITS_PER_CHAR		10
+#define GENI_UART_CONS_PORTS		1
+#define GENI_UART_PORTS			3
+#define DEF_FIFO_DEPTH_WORDS		16
+#define DEF_TX_WM			2
+#define DEF_FIFO_WIDTH_BITS		32
+#define UART_RX_WM			2
 
 /* SE_UART_LOOPBACK_CFG */
-#define RX_TX_SORTED	BIT(0)
-#define CTS_RTS_SORTED	BIT(1)
-#define RX_TX_CTS_RTS_SORTED	(RX_TX_SORTED | CTS_RTS_SORTED)
+#define RX_TX_SORTED			BIT(0)
+#define CTS_RTS_SORTED			BIT(1)
+#define RX_TX_CTS_RTS_SORTED		(RX_TX_SORTED | CTS_RTS_SORTED)
 
 /* UART pin swap value */
-#define DEFAULT_IO_MACRO_IO0_IO1_MASK		GENMASK(3, 0)
+#define DEFAULT_IO_MACRO_IO0_IO1_MASK	GENMASK(3, 0)
 #define IO_MACRO_IO0_SEL		0x3
-#define DEFAULT_IO_MACRO_IO2_IO3_MASK		GENMASK(15, 4)
+#define DEFAULT_IO_MACRO_IO2_IO3_MASK	GENMASK(15, 4)
 #define IO_MACRO_IO2_IO3_SWAP		0x4640
 
 /* We always configure 4 bytes per FIFO word */
-- 
2.37.2

[PATCH v3 04/13] tty: serial: qcom-geni-serial: improve the to_dev_port() macro

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The member we want to resolve in struct qcom_geni_serial_port is called
uport so we don't need an additional redundant parameter in this macro.

While at it: turn the macro into a static inline function.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 36 ++++++++++++++-------------
 1 file changed, 19 insertions(+), 17 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 97ee7c074b79..e4139718e084 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -133,8 +133,10 @@ static const struct uart_ops qcom_geni_uart_pops;
 static struct uart_driver qcom_geni_console_driver;
 static struct uart_driver qcom_geni_uart_driver;
 
-#define to_dev_port(ptr, member) \
-		container_of(ptr, struct qcom_geni_serial_port, member)
+static inline struct qcom_geni_serial_port *to_dev_port(struct uart_port *uport)
+{
+	return container_of(uport, struct qcom_geni_serial_port, uport);
+}
 
 static struct qcom_geni_serial_port qcom_geni_uart_ports[GENI_UART_PORTS] = {
 	[0] = {
@@ -175,7 +177,7 @@ static struct qcom_geni_serial_port qcom_geni_console_port = {
 static int qcom_geni_serial_request_port(struct uart_port *uport)
 {
 	struct platform_device *pdev = to_platform_device(uport->dev);
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	uport->membase = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(uport->membase))
@@ -212,7 +214,7 @@ static void qcom_geni_serial_set_mctrl(struct uart_port *uport,
 							unsigned int mctrl)
 {
 	u32 uart_manual_rfr = 0;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	if (uart_console(uport))
 		return;
@@ -253,7 +255,7 @@ static bool qcom_geni_serial_poll_bit(struct uart_port *uport,
 	struct qcom_geni_private_data *private_data = uport->private_data;
 
 	if (private_data->drv) {
-		port = to_dev_port(uport, uport);
+		port = to_dev_port(uport);
 		baud = port->baud;
 		if (!baud)
 			baud = 115200;
@@ -506,7 +508,7 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 	u32 i;
 	unsigned char buf[sizeof(u32)];
 	struct tty_port *tport;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	tport = &uport->state->port;
 	for (i = 0; i < bytes; ) {
@@ -549,7 +551,7 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
 {
 	struct tty_port *tport;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	u32 num_bytes_pw = port->tx_fifo_width / BITS_PER_BYTE;
 	u32 words = ALIGN(bytes, num_bytes_pw) / num_bytes_pw;
 	int ret;
@@ -598,7 +600,7 @@ static void qcom_geni_serial_stop_tx(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
 	irq_en &= ~(M_CMD_DONE_EN | M_TX_FIFO_WATERMARK_EN);
@@ -627,7 +629,7 @@ static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
 	u32 last_word_byte_cnt;
 	u32 last_word_partial;
 	u32 total_bytes;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	status = readl(uport->membase +	SE_GENI_RX_FIFO_STATUS);
 	word_cnt = status & RX_FIFO_WC_MSK;
@@ -649,7 +651,7 @@ static void qcom_geni_serial_stop_rx(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	u32 s_irq_status;
 
 	irq_en = readl(uport->membase + SE_GENI_S_IRQ_EN);
@@ -687,7 +689,7 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	status = readl(uport->membase + SE_GENI_STATUS);
 	if (status & S_GENI_CMD_ACTIVE)
@@ -707,7 +709,7 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
 static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 		bool active)
 {
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	struct circ_buf *xmit = &uport->state->xmit;
 	size_t avail;
 	size_t remaining;
@@ -803,7 +805,7 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 	struct uart_port *uport = dev;
 	bool drop_rx = false;
 	struct tty_port *tport = &uport->state->port;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	if (uport->suspended)
 		return IRQ_NONE;
@@ -869,7 +871,7 @@ static void qcom_geni_serial_shutdown(struct uart_port *uport)
 
 static int qcom_geni_serial_port_setup(struct uart_port *uport)
 {
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	u32 rxstale = DEFAULT_BITS_PER_CHAR * STALE_TIMEOUT;
 	u32 proto;
 	u32 pin_swap;
@@ -917,7 +919,7 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
 static int qcom_geni_serial_startup(struct uart_port *uport)
 {
 	int ret;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	if (!port->setup) {
 		ret = qcom_geni_serial_port_setup(uport);
@@ -1003,7 +1005,7 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
 	u32 stop_bit_len;
 	unsigned int clk_div;
 	u32 ser_clk_cfg;
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	unsigned long clk_rate;
 	u32 ver, sampling_rate;
 	unsigned int avg_bw_core;
@@ -1288,7 +1290,7 @@ static struct uart_driver qcom_geni_uart_driver = {
 static void qcom_geni_serial_pm(struct uart_port *uport,
 		unsigned int new_state, unsigned int old_state)
 {
-	struct qcom_geni_serial_port *port = to_dev_port(uport, uport);
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	/* If we've never been called, treat it as off */
 	if (old_state == UART_PM_STATE_UNDEFINED)
-- 
2.37.2

[PATCH v3 05/13] tty: serial: qcom-geni-serial: remove stray newlines

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Remove stray newlines around #ifdefs for consistency with the rest
of the driver code.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index e4139718e084..ec2523736e99 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -320,7 +320,6 @@ static void qcom_geni_serial_abort_rx(struct uart_port *uport)
 }
 
 #ifdef CONFIG_CONSOLE_POLL
-
 static int qcom_geni_serial_get_char(struct uart_port *uport)
 {
 	struct qcom_geni_private_data *private_data = uport->private_data;
@@ -545,7 +544,6 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 {
 	return -EPERM;
 }
-
 #endif /* CONFIG_SERIAL_QCOM_GENI_CONSOLE */
 
 static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
-- 
2.37.2

[PATCH v3 06/13] tty: serial: qcom-geni-serial: refactor qcom_geni_serial_isr()

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Simplify the conditions in qcom_geni_serial_isr() and fix indentation.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/tty/serial/qcom_geni_serial.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index ec2523736e99..fba02f71a874 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -827,20 +827,18 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 
 	if (m_irq_status & m_irq_en & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN))
 		qcom_geni_serial_handle_tx(uport, m_irq_status & M_CMD_DONE_EN,
-					geni_status & M_GENI_CMD_ACTIVE);
+					   geni_status & M_GENI_CMD_ACTIVE);
 
-	if (s_irq_status & S_GP_IRQ_0_EN || s_irq_status & S_GP_IRQ_1_EN) {
+	if (s_irq_status & (S_GP_IRQ_0_EN | S_GP_IRQ_1_EN)) {
 		if (s_irq_status & S_GP_IRQ_0_EN)
 			uport->icount.parity++;
 		drop_rx = true;
-	} else if (s_irq_status & S_GP_IRQ_2_EN ||
-					s_irq_status & S_GP_IRQ_3_EN) {
+	} else if (s_irq_status & (S_GP_IRQ_2_EN | S_GP_IRQ_3_EN)) {
 		uport->icount.brk++;
 		port->brk = true;
 	}
 
-	if (s_irq_status & S_RX_FIFO_WATERMARK_EN ||
-					s_irq_status & S_RX_FIFO_LAST_EN)
+	if (s_irq_status & (S_RX_FIFO_WATERMARK_EN | S_RX_FIFO_LAST_EN))
 		qcom_geni_serial_handle_rx(uport, drop_rx);
 
 out_unlock:
-- 
2.37.2

[PATCH v3 07/13] tty: serial: qcom-geni-serial: remove unneeded tabs

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Remove redundant indentation in struct member assignment.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index fba02f71a874..68a1402fbe58 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -141,26 +141,26 @@ static inline struct qcom_geni_serial_port *to_dev_port(struct uart_port *uport)
 static struct qcom_geni_serial_port qcom_geni_uart_ports[GENI_UART_PORTS] = {
 	[0] = {
 		.uport = {
-				.iotype = UPIO_MEM,
-				.ops = &qcom_geni_uart_pops,
-				.flags = UPF_BOOT_AUTOCONF,
-				.line = 0,
+			.iotype = UPIO_MEM,
+			.ops = &qcom_geni_uart_pops,
+			.flags = UPF_BOOT_AUTOCONF,
+			.line = 0,
 		},
 	},
 	[1] = {
 		.uport = {
-				.iotype = UPIO_MEM,
-				.ops = &qcom_geni_uart_pops,
-				.flags = UPF_BOOT_AUTOCONF,
-				.line = 1,
+			.iotype = UPIO_MEM,
+			.ops = &qcom_geni_uart_pops,
+			.flags = UPF_BOOT_AUTOCONF,
+			.line = 1,
 		},
 	},
 	[2] = {
 		.uport = {
-				.iotype = UPIO_MEM,
-				.ops = &qcom_geni_uart_pops,
-				.flags = UPF_BOOT_AUTOCONF,
-				.line = 2,
+			.iotype = UPIO_MEM,
+			.ops = &qcom_geni_uart_pops,
+			.flags = UPF_BOOT_AUTOCONF,
+			.line = 2,
 		},
 	},
 };
-- 
2.37.2

[PATCH v3 08/13] tty: serial: qcom-geni-serial: refactor qcom_geni_serial_handle_tx()

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

qcom_geni_serial_handle_tx() is pretty big, let's move the code that
handles the actual writing of data to a separate function which makes
sense in preparation for introducing a dma variant of handle_tx().

Let's also shuffle the code a bit, drop unneeded variables and use
uart_xmit_advance() instead of handling tail->xmit manually.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 54 +++++++++++++--------------
 1 file changed, 27 insertions(+), 27 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 68a1402fbe58..658b6d596f58 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -704,19 +704,42 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
 	writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
 }
 
+static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
+					     unsigned int chunk)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	struct circ_buf *xmit = &uport->state->xmit;
+	u8 buf[BYTES_PER_FIFO_WORD];
+	size_t remaining = chunk;
+	unsigned int tx_bytes;
+	int c;
+
+	while (remaining) {
+		memset(buf, 0, sizeof(buf));
+		tx_bytes = min_t(size_t, remaining, BYTES_PER_FIFO_WORD);
+
+		for (c = 0; c < tx_bytes ; c++) {
+			buf[c] = xmit->buf[xmit->tail];
+			uart_xmit_advance(uport, 1);
+		}
+
+		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);
+
+		remaining -= tx_bytes;
+		port->tx_remaining -= tx_bytes;
+	}
+}
+
 static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 		bool active)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	struct circ_buf *xmit = &uport->state->xmit;
 	size_t avail;
-	size_t remaining;
 	size_t pending;
-	int i;
 	u32 status;
 	u32 irq_en;
 	unsigned int chunk;
-	int tail;
 
 	status = readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
 
@@ -735,7 +758,6 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 	avail = port->tx_fifo_depth - (status & TX_FIFO_WC);
 	avail *= BYTES_PER_FIFO_WORD;
 
-	tail = xmit->tail;
 	chunk = min(avail, pending);
 	if (!chunk)
 		goto out_write_wakeup;
@@ -750,29 +772,7 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 					uport->membase + SE_GENI_M_IRQ_EN);
 	}
 
-	remaining = chunk;
-	for (i = 0; i < chunk; ) {
-		unsigned int tx_bytes;
-		u8 buf[sizeof(u32)];
-		int c;
-
-		memset(buf, 0, sizeof(buf));
-		tx_bytes = min_t(size_t, remaining, BYTES_PER_FIFO_WORD);
-
-		for (c = 0; c < tx_bytes ; c++) {
-			buf[c] = xmit->buf[tail++];
-			tail &= UART_XMIT_SIZE - 1;
-		}
-
-		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);
-
-		i += tx_bytes;
-		uport->icount.tx += tx_bytes;
-		remaining -= tx_bytes;
-		port->tx_remaining -= tx_bytes;
-	}
-
-	xmit->tail = tail;
+	qcom_geni_serial_send_chunk_fifo(uport, chunk);
 
 	/*
 	 * The tx fifo watermark is level triggered and latched. Though we had
-- 
2.37.2

[PATCH v3 09/13] tty: serial: qcom-geni-serial: drop the return value from handle_rx

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The return value of the handle_rx() callback is never checked. Drop it.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 658b6d596f58..d5c343b06c23 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -114,7 +114,7 @@ struct qcom_geni_serial_port {
 	u32 tx_fifo_width;
 	u32 rx_fifo_depth;
 	bool setup;
-	int (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
+	void (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
 	unsigned int baud;
 	void *rx_fifo;
 	u32 loopback;
@@ -502,7 +502,7 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s,
 		spin_unlock_irqrestore(&uport->lock, flags);
 }
 
-static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
+static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 {
 	u32 i;
 	unsigned char buf[sizeof(u32)];
@@ -537,16 +537,15 @@ static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 	}
 	if (!drop)
 		tty_flip_buffer_push(tport);
-	return 0;
 }
 #else
-static int handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
+static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 {
-	return -EPERM;
+
 }
 #endif /* CONFIG_SERIAL_QCOM_GENI_CONSOLE */
 
-static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
+static void handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
 {
 	struct tty_port *tport;
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
@@ -557,7 +556,7 @@ static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
 	tport = &uport->state->port;
 	ioread32_rep(uport->membase + SE_GENI_RX_FIFOn, port->rx_fifo, words);
 	if (drop)
-		return 0;
+		return;
 
 	ret = tty_insert_flip_string(tport, port->rx_fifo, bytes);
 	if (ret != bytes) {
@@ -567,7 +566,6 @@ static int handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
 	}
 	uport->icount.rx += ret;
 	tty_flip_buffer_push(tport);
-	return ret;
 }
 
 static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
-- 
2.37.2

[PATCH v3 10/13] tty: serial: qcom-geni-serial: use of_device_id data

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Instead of checking the device compatible in probe(), assign the
device-specific data to struct of_device_id. We'll use it later when
providing SE DMA support.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 46 ++++++++++++++++++++-------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index d5c343b06c23..036231106321 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -95,6 +95,11 @@
 /* We always configure 4 bytes per FIFO word */
 #define BYTES_PER_FIFO_WORD		4
 
+struct qcom_geni_device_data {
+	bool console;
+	void (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
+};
+
 struct qcom_geni_private_data {
 	/* NOTE: earlycon port will have NULL here */
 	struct uart_driver *drv;
@@ -114,7 +119,6 @@ struct qcom_geni_serial_port {
 	u32 tx_fifo_width;
 	u32 rx_fifo_depth;
 	bool setup;
-	void (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
 	unsigned int baud;
 	void *rx_fifo;
 	u32 loopback;
@@ -126,6 +130,7 @@ struct qcom_geni_serial_port {
 	bool cts_rts_swap;
 
 	struct qcom_geni_private_data private_data;
+	const struct qcom_geni_device_data *dev_data;
 };
 
 static const struct uart_ops qcom_geni_console_pops;
@@ -640,7 +645,7 @@ static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
 		total_bytes += last_word_byte_cnt;
 	else
 		total_bytes += BYTES_PER_FIFO_WORD;
-	port->handle_rx(uport, total_bytes, drop);
+	port->dev_data->handle_rx(uport, total_bytes, drop);
 }
 
 static void qcom_geni_serial_stop_rx(struct uart_port *uport)
@@ -1345,13 +1350,14 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	struct uart_port *uport;
 	struct resource *res;
 	int irq;
-	bool console = false;
 	struct uart_driver *drv;
+	const struct qcom_geni_device_data *data;
 
-	if (of_device_is_compatible(pdev->dev.of_node, "qcom,geni-debug-uart"))
-		console = true;
+	data = of_device_get_match_data(&pdev->dev);
+	if (!data)
+		return -EINVAL;
 
-	if (console) {
+	if (data->console) {
 		drv = &qcom_geni_console_driver;
 		line = of_alias_get_id(pdev->dev.of_node, "serial");
 	} else {
@@ -1361,7 +1367,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 			line = of_alias_get_id(pdev->dev.of_node, "hsuart");
 	}
 
-	port = get_port_from_line(line, console);
+	port = get_port_from_line(line, data->console);
 	if (IS_ERR(port)) {
 		dev_err(&pdev->dev, "Invalid line %d\n", line);
 		return PTR_ERR(port);
@@ -1373,6 +1379,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	uport->dev = &pdev->dev;
+	port->dev_data = data;
 	port->se.dev = &pdev->dev;
 	port->se.wrapper = dev_get_drvdata(pdev->dev.parent);
 	port->se.clk = devm_clk_get(&pdev->dev, "se");
@@ -1391,7 +1398,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	port->rx_fifo_depth = DEF_FIFO_DEPTH_WORDS;
 	port->tx_fifo_width = DEF_FIFO_WIDTH_BITS;
 
-	if (!console) {
+	if (!data->console) {
 		port->rx_fifo = devm_kcalloc(uport->dev,
 			port->rx_fifo_depth, sizeof(u32), GFP_KERNEL);
 		if (!port->rx_fifo)
@@ -1421,7 +1428,7 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	uport->irq = irq;
 	uport->has_sysrq = IS_ENABLED(CONFIG_SERIAL_QCOM_GENI_CONSOLE);
 
-	if (!console)
+	if (!data->console)
 		port->wakeup_irq = platform_get_irq_optional(pdev, 1);
 
 	if (of_property_read_bool(pdev->dev.of_node, "rx-tx-swap"))
@@ -1443,7 +1450,6 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	port->private_data.drv = drv;
 	uport->private_data = &port->private_data;
 	platform_set_drvdata(pdev, port);
-	port->handle_rx = console ? handle_rx_console : handle_rx_uart;
 
 	ret = uart_add_one_port(drv, uport);
 	if (ret)
@@ -1523,14 +1529,30 @@ static int __maybe_unused qcom_geni_serial_sys_resume(struct device *dev)
 	return ret;
 }
 
+static const struct qcom_geni_device_data qcom_geni_console_data = {
+	.console = true,
+	.handle_rx = handle_rx_console,
+};
+
+static const struct qcom_geni_device_data qcom_geni_uart_data = {
+	.console = false,
+	.handle_rx = handle_rx_uart,
+};
+
 static const struct dev_pm_ops qcom_geni_serial_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(qcom_geni_serial_sys_suspend,
 					qcom_geni_serial_sys_resume)
 };
 
 static const struct of_device_id qcom_geni_serial_match_table[] = {
-	{ .compatible = "qcom,geni-debug-uart", },
-	{ .compatible = "qcom,geni-uart", },
+	{
+		.compatible = "qcom,geni-debug-uart",
+		.data = &qcom_geni_console_data,
+	},
+	{
+		.compatible = "qcom,geni-uart",
+		.data = &qcom_geni_uart_data,
+	},
 	{}
 };
 MODULE_DEVICE_TABLE(of, qcom_geni_serial_match_table);
-- 
2.37.2

[PATCH v3 11/13] tty: serial: qcom-geni-serial: stop operations in progress at shutdown

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

We don't stop transmissions in progress at shutdown. This is fine with
FIFO SE mode but with DMA it causes trouble so fix it now.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 036231106321..82242a40a95a 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -865,6 +865,9 @@ static void get_tx_fifo_size(struct qcom_geni_serial_port *port)
 
 static void qcom_geni_serial_shutdown(struct uart_port *uport)
 {
+	qcom_geni_serial_stop_tx(uport);
+	qcom_geni_serial_stop_rx(uport);
+
 	disable_irq(uport->irq);
 }
 
-- 
2.37.2

[PATCH v3 12/13] soc: qcom-geni-se: add more symbol definitions

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The following symbols will be used when adding support for SE DMA in
the qcom geni serial driver.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
---
 include/linux/qcom-geni-se.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/include/linux/qcom-geni-se.h b/include/linux/qcom-geni-se.h
index f5672785c0c4..400213daa461 100644
--- a/include/linux/qcom-geni-se.h
+++ b/include/linux/qcom-geni-se.h
@@ -103,6 +103,7 @@ struct geni_se {
 #define SE_DMA_TX_FSM_RST		0xc58
 #define SE_DMA_RX_IRQ_STAT		0xd40
 #define SE_DMA_RX_IRQ_CLR		0xd44
+#define SE_DMA_RX_LEN_IN		0xd54
 #define SE_DMA_RX_FSM_RST		0xd58
 #define SE_HW_PARAM_0			0xe24
 #define SE_HW_PARAM_1			0xe28
@@ -235,6 +236,8 @@ struct geni_se {
 #define RX_SBE				BIT(2)
 #define RX_RESET_DONE			BIT(3)
 #define RX_FLUSH_DONE			BIT(4)
+#define RX_DMA_PARITY_ERR		BIT(5)
+#define RX_DMA_BREAK			GENMASK(8, 7)
 #define RX_GENI_GP_IRQ			GENMASK(10, 5)
 #define RX_GENI_CANCEL_IRQ		BIT(11)
 #define RX_GENI_GP_IRQ_EXT		GENMASK(13, 12)
-- 
2.37.2

[PATCH v3 13/13] tty: serial: qcom-geni-serial: add support for serial engine DMA

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

The qcom-geni-serial driver currently only works in SE FIFO mode. This
limits the UART speed to around 180 kB/s. In order to achieve higher
speeds we need to use SE DMA mode.

Keep the console port working in FIFO mode but extend the code to use DMA
for the high-speed port.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/tty/serial/qcom_geni_serial.c | 289 ++++++++++++++++++++++----
 1 file changed, 247 insertions(+), 42 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 82242a40a95a..0f4ba909c792 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -70,6 +70,8 @@
 #define UART_START_TX			0x1
 /* UART S_CMD OP codes */
 #define UART_START_READ			0x1
+#define UART_PARAM			0x1
+#define UART_PARAM_RFR_OPEN		BIT(7)
 
 #define UART_OVERSAMPLING		32
 #define STALE_TIMEOUT			16
@@ -95,9 +97,11 @@
 /* We always configure 4 bytes per FIFO word */
 #define BYTES_PER_FIFO_WORD		4
 
+#define DMA_RX_BUF_SIZE		2048
+
 struct qcom_geni_device_data {
 	bool console;
-	void (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
+	enum geni_se_xfer_mode mode;
 };
 
 struct qcom_geni_private_data {
@@ -118,9 +122,11 @@ struct qcom_geni_serial_port {
 	u32 tx_fifo_depth;
 	u32 tx_fifo_width;
 	u32 rx_fifo_depth;
+	dma_addr_t tx_dma_addr;
+	dma_addr_t rx_dma_addr;
 	bool setup;
 	unsigned int baud;
-	void *rx_fifo;
+	void *rx_buf;
 	u32 loopback;
 	bool brk;
 
@@ -552,18 +558,11 @@ static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
 
 static void handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
 {
-	struct tty_port *tport;
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
-	u32 num_bytes_pw = port->tx_fifo_width / BITS_PER_BYTE;
-	u32 words = ALIGN(bytes, num_bytes_pw) / num_bytes_pw;
+	struct tty_port *tport = &uport->state->port;
 	int ret;
 
-	tport = &uport->state->port;
-	ioread32_rep(uport->membase + SE_GENI_RX_FIFOn, port->rx_fifo, words);
-	if (drop)
-		return;
-
-	ret = tty_insert_flip_string(tport, port->rx_fifo, bytes);
+	ret = tty_insert_flip_string(tport, port->rx_buf, bytes);
 	if (ret != bytes) {
 		dev_err(uport->dev, "%s:Unable to push data ret %d_bytes %d\n",
 				__func__, ret, bytes);
@@ -578,7 +577,70 @@ static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
 	return !readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
 }
 
-static void qcom_geni_serial_start_tx(struct uart_port *uport)
+static void qcom_geni_serial_stop_tx_dma(struct uart_port *uport)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	bool done;
+	u32 status;
+	u32 m_irq_en;
+
+	status = readl(uport->membase + SE_GENI_STATUS);
+	if (!(status & M_GENI_CMD_ACTIVE))
+		return;
+
+	if (port->rx_dma_addr) {
+		geni_se_tx_dma_unprep(&port->se, port->tx_dma_addr,
+				      port->tx_remaining);
+		port->tx_dma_addr = (dma_addr_t)NULL;
+		port->tx_remaining = 0;
+	}
+
+	m_irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
+	writel(m_irq_en, uport->membase + SE_GENI_M_IRQ_EN);
+	geni_se_cancel_m_cmd(&port->se);
+
+	done = qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS,
+					 S_CMD_CANCEL_EN, true);
+	if (!done) {
+		geni_se_abort_m_cmd(&port->se);
+		qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
+					  M_CMD_ABORT_EN, true);
+		writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
+	}
+
+	writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
+}
+
+static void qcom_geni_serial_start_tx_dma(struct uart_port *uport)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	struct circ_buf *xmit = &uport->state->xmit;
+	unsigned int xmit_size;
+	int ret;
+
+	if (port->tx_dma_addr)
+		return;
+
+	xmit_size = uart_circ_chars_pending(xmit);
+	if (xmit_size < WAKEUP_CHARS)
+		uart_write_wakeup(uport);
+
+	xmit_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+
+	qcom_geni_serial_setup_tx(uport, xmit_size);
+
+	ret = geni_se_tx_dma_prep(&port->se, &xmit->buf[xmit->tail],
+				  xmit_size, &port->tx_dma_addr);
+	if (ret) {
+		dev_err(uport->dev, "unable to start TX SE DMA: %d\n", ret);
+		qcom_geni_serial_stop_tx_dma(uport);
+		return;
+	}
+
+	port->tx_remaining = xmit_size;
+}
+
+static void qcom_geni_serial_start_tx_fifo(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
@@ -597,7 +659,7 @@ static void qcom_geni_serial_start_tx(struct uart_port *uport)
 	writel(irq_en, uport->membase +	SE_GENI_M_IRQ_EN);
 }
 
-static void qcom_geni_serial_stop_tx(struct uart_port *uport)
+static void qcom_geni_serial_stop_tx_fifo(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
@@ -623,14 +685,13 @@ static void qcom_geni_serial_stop_tx(struct uart_port *uport)
 	writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
 }
 
-static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
+static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop)
 {
 	u32 status;
 	u32 word_cnt;
 	u32 last_word_byte_cnt;
 	u32 last_word_partial;
 	u32 total_bytes;
-	struct qcom_geni_serial_port *port = to_dev_port(uport);
 
 	status = readl(uport->membase +	SE_GENI_RX_FIFO_STATUS);
 	word_cnt = status & RX_FIFO_WC_MSK;
@@ -645,10 +706,10 @@ static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop)
 		total_bytes += last_word_byte_cnt;
 	else
 		total_bytes += BYTES_PER_FIFO_WORD;
-	port->dev_data->handle_rx(uport, total_bytes, drop);
+	handle_rx_console(uport, total_bytes, drop);
 }
 
-static void qcom_geni_serial_stop_rx(struct uart_port *uport)
+static void qcom_geni_serial_stop_rx_fifo(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
@@ -678,7 +739,7 @@ static void qcom_geni_serial_stop_rx(struct uart_port *uport)
 	s_irq_status = readl(uport->membase + SE_GENI_S_IRQ_STATUS);
 	/* Flush the Rx buffer */
 	if (s_irq_status & S_RX_FIFO_LAST_EN)
-		qcom_geni_serial_handle_rx(uport, true);
+		qcom_geni_serial_handle_rx_fifo(uport, true);
 	writel(s_irq_status, uport->membase + SE_GENI_S_IRQ_CLEAR);
 
 	status = readl(uport->membase + SE_GENI_STATUS);
@@ -686,7 +747,7 @@ static void qcom_geni_serial_stop_rx(struct uart_port *uport)
 		qcom_geni_serial_abort_rx(uport);
 }
 
-static void qcom_geni_serial_start_rx(struct uart_port *uport)
+static void qcom_geni_serial_start_rx_fifo(struct uart_port *uport)
 {
 	u32 irq_en;
 	u32 status;
@@ -694,7 +755,7 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
 
 	status = readl(uport->membase + SE_GENI_STATUS);
 	if (status & S_GENI_CMD_ACTIVE)
-		qcom_geni_serial_stop_rx(uport);
+		qcom_geni_serial_stop_rx_fifo(uport);
 
 	geni_se_setup_s_cmd(&port->se, UART_START_READ, 0);
 
@@ -707,6 +768,101 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
 	writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
 }
 
+static void qcom_geni_serial_stop_rx_dma(struct uart_port *uport)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	u32 status;
+
+	status = readl(uport->membase + SE_GENI_STATUS);
+	if (!(status & S_GENI_CMD_ACTIVE))
+		return;
+
+	geni_se_cancel_s_cmd(&port->se);
+	qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS,
+				  S_CMD_CANCEL_EN, true);
+
+	status = readl(uport->membase + SE_GENI_STATUS);
+	if (status & S_GENI_CMD_ACTIVE)
+		qcom_geni_serial_abort_rx(uport);
+
+	if (port->rx_dma_addr) {
+		geni_se_rx_dma_unprep(&port->se, port->rx_dma_addr,
+				      DMA_RX_BUF_SIZE);
+		port->rx_dma_addr = (dma_addr_t)NULL;
+	}
+}
+
+static void qcom_geni_serial_start_rx_dma(struct uart_port *uport)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	u32 status;
+	int ret;
+
+	status = readl(uport->membase + SE_GENI_STATUS);
+	if (status & S_GENI_CMD_ACTIVE)
+		qcom_geni_serial_stop_rx_dma(uport);
+
+	geni_se_setup_s_cmd(&port->se, UART_START_READ, UART_PARAM_RFR_OPEN);
+
+	ret = geni_se_rx_dma_prep(&port->se, port->rx_buf,
+				  DMA_RX_BUF_SIZE,
+				  &port->rx_dma_addr);
+	if (ret) {
+		dev_err(uport->dev, "unable to start RX SE DMA: %d\n", ret);
+		qcom_geni_serial_stop_rx_dma(uport);
+	}
+}
+
+static void qcom_geni_serial_handle_rx_dma(struct uart_port *uport, bool drop)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	u32 status;
+	u32 rx_in;
+	int ret;
+
+	status = readl(uport->membase + SE_GENI_STATUS);
+	if (!(status & S_GENI_CMD_ACTIVE))
+		return;
+
+	if (!port->rx_dma_addr)
+		return;
+
+	geni_se_rx_dma_unprep(&port->se, port->rx_dma_addr, DMA_RX_BUF_SIZE);
+	port->rx_dma_addr = (dma_addr_t)NULL;
+
+	rx_in = readl(uport->membase + SE_DMA_RX_LEN_IN);
+	if (!rx_in) {
+		dev_warn(uport->dev, "serial engine reports 0 RX bytes in!\n");
+		return;
+	}
+
+	if (!drop)
+		handle_rx_uart(uport, rx_in, drop);
+
+	ret = geni_se_rx_dma_prep(&port->se, port->rx_buf,
+				  DMA_RX_BUF_SIZE,
+				  &port->rx_dma_addr);
+	if (ret) {
+		dev_err(uport->dev, "unable to start RX SE DMA: %d\n", ret);
+		qcom_geni_serial_stop_rx_dma(uport);
+	}
+}
+
+static void qcom_geni_serial_start_rx(struct uart_port *uport)
+{
+	uport->ops->start_rx(uport);
+}
+
+static void qcom_geni_serial_stop_rx(struct uart_port *uport)
+{
+	uport->ops->stop_rx(uport);
+}
+
+static void qcom_geni_serial_stop_tx(struct uart_port *uport)
+{
+	uport->ops->stop_tx(uport);
+}
+
 static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
 					     unsigned int chunk)
 {
@@ -733,8 +889,8 @@ static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
 	}
 }
 
-static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
-		bool active)
+static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport,
+					    bool done, bool active)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	struct circ_buf *xmit = &uport->state->xmit;
@@ -754,7 +910,7 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 
 	/* All data has been transmitted and acknowledged as received */
 	if (!pending && !status && done) {
-		qcom_geni_serial_stop_tx(uport);
+		qcom_geni_serial_stop_tx_fifo(uport);
 		goto out_write_wakeup;
 	}
 
@@ -797,12 +953,32 @@ static void qcom_geni_serial_handle_tx(struct uart_port *uport, bool done,
 		uart_write_wakeup(uport);
 }
 
+static void qcom_geni_serial_handle_tx_dma(struct uart_port *uport)
+{
+	struct qcom_geni_serial_port *port = to_dev_port(uport);
+	struct circ_buf *xmit = &uport->state->xmit;
+
+	uart_xmit_advance(uport, port->tx_remaining);
+	geni_se_tx_dma_unprep(&port->se, port->tx_dma_addr, port->tx_remaining);
+	port->tx_dma_addr = (dma_addr_t)NULL;
+	port->tx_remaining = 0;
+
+	if (!uart_circ_empty(xmit))
+		qcom_geni_serial_start_tx_dma(uport);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(uport);
+}
+
 static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 {
 	u32 m_irq_en;
 	u32 m_irq_status;
 	u32 s_irq_status;
 	u32 geni_status;
+	u32 dma;
+	u32 dma_tx_status;
+	u32 dma_rx_status;
 	struct uart_port *uport = dev;
 	bool drop_rx = false;
 	struct tty_port *tport = &uport->state->port;
@@ -815,10 +991,15 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 
 	m_irq_status = readl(uport->membase + SE_GENI_M_IRQ_STATUS);
 	s_irq_status = readl(uport->membase + SE_GENI_S_IRQ_STATUS);
+	dma_tx_status = readl(uport->membase + SE_DMA_TX_IRQ_STAT);
+	dma_rx_status = readl(uport->membase + SE_DMA_RX_IRQ_STAT);
 	geni_status = readl(uport->membase + SE_GENI_STATUS);
+	dma = readl(uport->membase + SE_GENI_DMA_MODE_EN);
 	m_irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
 	writel(m_irq_status, uport->membase + SE_GENI_M_IRQ_CLEAR);
 	writel(s_irq_status, uport->membase + SE_GENI_S_IRQ_CLEAR);
+	writel(dma_tx_status, uport->membase + SE_DMA_TX_IRQ_CLR);
+	writel(dma_rx_status, uport->membase + SE_DMA_RX_IRQ_CLR);
 
 	if (WARN_ON(m_irq_status & M_ILLEGAL_CMD_EN))
 		goto out_unlock;
@@ -828,10 +1009,6 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 	}
 
-	if (m_irq_status & m_irq_en & (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN))
-		qcom_geni_serial_handle_tx(uport, m_irq_status & M_CMD_DONE_EN,
-					   geni_status & M_GENI_CMD_ACTIVE);
-
 	if (s_irq_status & (S_GP_IRQ_0_EN | S_GP_IRQ_1_EN)) {
 		if (s_irq_status & S_GP_IRQ_0_EN)
 			uport->icount.parity++;
@@ -841,8 +1018,35 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 		port->brk = true;
 	}
 
-	if (s_irq_status & (S_RX_FIFO_WATERMARK_EN | S_RX_FIFO_LAST_EN))
-		qcom_geni_serial_handle_rx(uport, drop_rx);
+	if (dma) {
+		if (dma_tx_status & TX_DMA_DONE)
+			qcom_geni_serial_handle_tx_dma(uport);
+
+		if (dma_rx_status) {
+			if (dma_rx_status & RX_RESET_DONE)
+				goto out_unlock;
+
+			if (dma_rx_status & RX_DMA_PARITY_ERR) {
+				uport->icount.parity++;
+				drop_rx = true;
+			}
+
+			if (dma_rx_status & RX_DMA_BREAK)
+				uport->icount.brk++;
+
+			if (dma_rx_status & (RX_DMA_DONE | RX_EOT))
+				qcom_geni_serial_handle_rx_dma(uport, drop_rx);
+		}
+	} else {
+		if (m_irq_status & m_irq_en &
+		    (M_TX_FIFO_WATERMARK_EN | M_CMD_DONE_EN))
+			qcom_geni_serial_handle_tx_fifo(uport,
+					m_irq_status & M_CMD_DONE_EN,
+					geni_status & M_GENI_CMD_ACTIVE);
+
+		if (s_irq_status & (S_RX_FIFO_WATERMARK_EN | S_RX_FIFO_LAST_EN))
+			qcom_geni_serial_handle_rx_fifo(uport, drop_rx);
+	}
 
 out_unlock:
 	uart_unlock_and_check_sysrq(uport);
@@ -912,7 +1116,7 @@ static int qcom_geni_serial_port_setup(struct uart_port *uport)
 	geni_se_config_packing(&port->se, BITS_PER_BYTE, BYTES_PER_FIFO_WORD,
 			       false, true, true);
 	geni_se_init(&port->se, UART_RX_WM, port->rx_fifo_depth - 2);
-	geni_se_select_mode(&port->se, GENI_SE_FIFO);
+	geni_se_select_mode(&port->se, port->dev_data->mode);
 	port->setup = true;
 
 	return 0;
@@ -1310,10 +1514,10 @@ static void qcom_geni_serial_pm(struct uart_port *uport,
 
 static const struct uart_ops qcom_geni_console_pops = {
 	.tx_empty = qcom_geni_serial_tx_empty,
-	.stop_tx = qcom_geni_serial_stop_tx,
-	.start_tx = qcom_geni_serial_start_tx,
-	.stop_rx = qcom_geni_serial_stop_rx,
-	.start_rx = qcom_geni_serial_start_rx,
+	.stop_tx = qcom_geni_serial_stop_tx_fifo,
+	.start_tx = qcom_geni_serial_start_tx_fifo,
+	.stop_rx = qcom_geni_serial_stop_rx_fifo,
+	.start_rx = qcom_geni_serial_start_rx_fifo,
 	.set_termios = qcom_geni_serial_set_termios,
 	.startup = qcom_geni_serial_startup,
 	.request_port = qcom_geni_serial_request_port,
@@ -1331,9 +1535,10 @@ static const struct uart_ops qcom_geni_console_pops = {
 
 static const struct uart_ops qcom_geni_uart_pops = {
 	.tx_empty = qcom_geni_serial_tx_empty,
-	.stop_tx = qcom_geni_serial_stop_tx,
-	.start_tx = qcom_geni_serial_start_tx,
-	.stop_rx = qcom_geni_serial_stop_rx,
+	.stop_tx = qcom_geni_serial_stop_tx_dma,
+	.start_tx = qcom_geni_serial_start_tx_dma,
+	.start_rx = qcom_geni_serial_start_rx_dma,
+	.stop_rx = qcom_geni_serial_stop_rx_dma,
 	.set_termios = qcom_geni_serial_set_termios,
 	.startup = qcom_geni_serial_startup,
 	.request_port = qcom_geni_serial_request_port,
@@ -1402,9 +1607,9 @@ static int qcom_geni_serial_probe(struct platform_device *pdev)
 	port->tx_fifo_width = DEF_FIFO_WIDTH_BITS;
 
 	if (!data->console) {
-		port->rx_fifo = devm_kcalloc(uport->dev,
-			port->rx_fifo_depth, sizeof(u32), GFP_KERNEL);
-		if (!port->rx_fifo)
+		port->rx_buf = devm_kzalloc(uport->dev,
+					    DMA_RX_BUF_SIZE, GFP_KERNEL);
+		if (!port->rx_buf)
 			return -ENOMEM;
 	}
 
@@ -1534,12 +1739,12 @@ static int __maybe_unused qcom_geni_serial_sys_resume(struct device *dev)
 
 static const struct qcom_geni_device_data qcom_geni_console_data = {
 	.console = true,
-	.handle_rx = handle_rx_console,
+	.mode = GENI_SE_FIFO,
 };
 
 static const struct qcom_geni_device_data qcom_geni_uart_data = {
 	.console = false,
-	.handle_rx = handle_rx_uart,
+	.mode = GENI_SE_DMA,
 };
 
 static const struct dev_pm_ops qcom_geni_serial_pm_ops = {
-- 
2.37.2

Re: [PATCH v3 08/13] tty: serial: qcom-geni-serial: refactor qcom_geni_serial_handle_tx()

[Jiri Slaby]

On 23. 11. 22, 12:07, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> qcom_geni_serial_handle_tx() is pretty big, let's move the code that
> handles the actual writing of data to a separate function which makes
> sense in preparation for introducing a dma variant of handle_tx().
> 
> Let's also shuffle the code a bit, drop unneeded variables and use
> uart_xmit_advance() instead of handling tail->xmit manually.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
>   drivers/tty/serial/qcom_geni_serial.c | 54 +++++++++++++--------------
>   1 file changed, 27 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> index 68a1402fbe58..658b6d596f58 100644
> --- a/drivers/tty/serial/qcom_geni_serial.c
> +++ b/drivers/tty/serial/qcom_geni_serial.c
> @@ -704,19 +704,42 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
>   	writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
>   }

I know you just shuffle the code, but:

> +static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
> +					     unsigned int chunk)
> +{
> +	struct qcom_geni_serial_port *port = to_dev_port(uport);
> +	struct circ_buf *xmit = &uport->state->xmit;
> +	u8 buf[BYTES_PER_FIFO_WORD];
> +	size_t remaining = chunk;

Why size_t when the others are uints? Well, BYTES_PER_FIFO_WORD should 
be defined as 4U.

> +	unsigned int tx_bytes;
> +	int c;
> +
> +	while (remaining) {
> +		memset(buf, 0, sizeof(buf));
> +		tx_bytes = min_t(size_t, remaining, BYTES_PER_FIFO_WORD);

Then, no need for min_t.

> +
> +		for (c = 0; c < tx_bytes ; c++) {
> +			buf[c] = xmit->buf[xmit->tail];
> +			uart_xmit_advance(uport, 1);
> +		}
> +
> +		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);

I wonder, why is _rep variant used to transfer a single word? Only to 
hide the cast?

thanks,
-- 
js
suse labs

Re: [PATCH v3 08/13] tty: serial: qcom-geni-serial: refactor qcom_geni_serial_handle_tx()

[Bartosz Golaszewski]

On Thu, Nov 24, 2022 at 8:18 AM Jiri Slaby <jirislaby@kernel.org> wrote:
>
> On 23. 11. 22, 12:07, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > qcom_geni_serial_handle_tx() is pretty big, let's move the code that
> > handles the actual writing of data to a separate function which makes
> > sense in preparation for introducing a dma variant of handle_tx().
> >
> > Let's also shuffle the code a bit, drop unneeded variables and use
> > uart_xmit_advance() instead of handling tail->xmit manually.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> >   drivers/tty/serial/qcom_geni_serial.c | 54 +++++++++++++--------------
> >   1 file changed, 27 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> > index 68a1402fbe58..658b6d596f58 100644
> > --- a/drivers/tty/serial/qcom_geni_serial.c
> > +++ b/drivers/tty/serial/qcom_geni_serial.c
> > @@ -704,19 +704,42 @@ static void qcom_geni_serial_start_rx(struct uart_port *uport)
> >       writel(irq_en, uport->membase + SE_GENI_M_IRQ_EN);
> >   }
>
> I know you just shuffle the code, but:
>
> > +static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
> > +                                          unsigned int chunk)
> > +{
> > +     struct qcom_geni_serial_port *port = to_dev_port(uport);
> > +     struct circ_buf *xmit = &uport->state->xmit;
> > +     u8 buf[BYTES_PER_FIFO_WORD];
> > +     size_t remaining = chunk;
>
> Why size_t when the others are uints? Well, BYTES_PER_FIFO_WORD should
> be defined as 4U.

Good point.

>
> > +     unsigned int tx_bytes;
> > +     int c;
> > +
> > +     while (remaining) {
> > +             memset(buf, 0, sizeof(buf));
> > +             tx_bytes = min_t(size_t, remaining, BYTES_PER_FIFO_WORD);
>
> Then, no need for min_t.
>

Same.

> > +
> > +             for (c = 0; c < tx_bytes ; c++) {
> > +                     buf[c] = xmit->buf[xmit->tail];
> > +                     uart_xmit_advance(uport, 1);
> > +             }
> > +
> > +             iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);
>
> I wonder, why is _rep variant used to transfer a single word? Only to
> hide the cast?
>

Even if - using writel() with a cast doesn't seem to improve the
performance and this one looks prettier IMO.

Bartosz

Re: [PATCH v3 13/13] tty: serial: qcom-geni-serial: add support for serial engine DMA

[Srinivas Kandagatla]

Thanks Bartosz for the patch,

On 23/11/2022 11:07, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> The qcom-geni-serial driver currently only works in SE FIFO mode. This
> limits the UART speed to around 180 kB/s. In order to achieve higher
> speeds we need to use SE DMA mode.
> 
> Keep the console port working in FIFO mode but extend the code to use DMA
> for the high-speed port.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
>   drivers/tty/serial/qcom_geni_serial.c | 289 ++++++++++++++++++++++----
>   1 file changed, 247 insertions(+), 42 deletions(-)
> 
> diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
> index 82242a40a95a..0f4ba909c792 100644
> --- a/drivers/tty/serial/qcom_geni_serial.c
> +++ b/drivers/tty/serial/qcom_geni_serial.c
> @@ -70,6 +70,8 @@
>   #define UART_START_TX			0x1
>   /* UART S_CMD OP codes */
>   #define UART_START_READ			0x1
> +#define UART_PARAM			0x1
> +#define UART_PARAM_RFR_OPEN		BIT(7)
>   
>   #define UART_OVERSAMPLING		32
>   #define STALE_TIMEOUT			16
> @@ -95,9 +97,11 @@
>   /* We always configure 4 bytes per FIFO word */
>   #define BYTES_PER_FIFO_WORD		4
>   
> +#define DMA_RX_BUF_SIZE		2048
> +
>   struct qcom_geni_device_data {
>   	bool console;
> -	void (*handle_rx)(struct uart_port *uport, u32 bytes, bool drop);
> +	enum geni_se_xfer_mode mode;
>   };
>   
>   struct qcom_geni_private_data {
> @@ -118,9 +122,11 @@ struct qcom_geni_serial_port {
>   	u32 tx_fifo_depth;
>   	u32 tx_fifo_width;
>   	u32 rx_fifo_depth;
> +	dma_addr_t tx_dma_addr;
> +	dma_addr_t rx_dma_addr;
>   	bool setup;
>   	unsigned int baud;
> -	void *rx_fifo;
> +	void *rx_buf;
>   	u32 loopback;
>   	bool brk;
>   
> @@ -552,18 +558,11 @@ static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
>   
>   static void handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
>   {
> -	struct tty_port *tport;
>   	struct qcom_geni_serial_port *port = to_dev_port(uport);
> -	u32 num_bytes_pw = port->tx_fifo_width / BITS_PER_BYTE;
> -	u32 words = ALIGN(bytes, num_bytes_pw) / num_bytes_pw;
> +	struct tty_port *tport = &uport->state->port;
>   	int ret;
>   
> -	tport = &uport->state->port;
> -	ioread32_rep(uport->membase + SE_GENI_RX_FIFOn, port->rx_fifo, words);
> -	if (drop)
> -		return;
> -

Are we removing FIFO support for uart?

It it not a overhead to use dma for small transfers that are less than 
fifo size?


> -	ret = tty_insert_flip_string(tport, port->rx_fifo, bytes);
> +	ret = tty_insert_flip_string(tport, port->rx_buf, bytes);
>   	if (ret != bytes) {
>   		dev_err(uport->dev, "%s:Unable to push data ret %d_bytes %d\n",
>   				__func__, ret, bytes);
> @@ -578,7 +577,70 @@ static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
>   	return !readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
>   }
>   
> -static void qcom_geni_serial_start_tx(struct uart_port *uport)
> +static void qcom_geni_serial_stop_tx_dma(struct uart_port *uport)
> +{
> +	struct qcom_geni_serial_port *port = to_dev_port(uport);
> +	bool done;

-->
> +	u32 status;
...
> +
> +	status = readl(uport->membase + SE_GENI_STATUS);
> +	if (!(status & M_GENI_CMD_ACTIVE))
> +		return;
<---

this code snippet is repeating more than few times in the patches, looks 
like it could be made to a inline helper.


> +
> +	if (port->rx_dma_addr) {
> +		geni_se_tx_dma_unprep(&port->se, port->tx_dma_addr,
> +				      port->tx_remaining);
> +		port->tx_dma_addr = (dma_addr_t)NULL;
> +		port->tx_remaining = 0;
> +	}
> +
> +	m_irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
> +	writel(m_irq_en, uport->membase + SE_GENI_M_IRQ_EN);
> +	geni_se_cancel_m_cmd(&port->se);
> +
> +	done = qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS,
> +					 S_CMD_CANCEL_EN, true);
> +	if (!done) {
> +		geni_se_abort_m_cmd(&port->se);
> +		qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
> +					  M_CMD_ABORT_EN, true);

return is not checked, there are few more such instances in the patch.

> +		writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
> +	}
> +
> +	writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
> +}
> +
> +static void qcom_geni_serial_start_tx_dma(struct uart_port *uport)
> +{
> +	struct qcom_geni_serial_port *port = to_dev_port(uport);
> +	struct circ_buf *xmit = &uport->state->xmit;
> +	unsigned int xmit_size;
> +	int ret;
> +
> +	if (port->tx_dma_addr)
> +		return;
Is this condition actually possible?


> +
> +	xmit_size = uart_circ_chars_pending(xmit);
> +	if (xmit_size < WAKEUP_CHARS)
> +		uart_write_wakeup(uport);
> +
> +	xmit_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
> +
> +	qcom_geni_serial_setup_tx(uport, xmit_size);
> +
> +	ret = geni_se_tx_dma_prep(&port->se, &xmit->buf[xmit->tail],
> +				  xmit_size, &port->tx_dma_addr);
> +	if (ret) {
> +		dev_err(uport->dev, "unable to start TX SE DMA: %d\n", ret);
> +		qcom_geni_serial_stop_tx_dma(uport);
> +		return;
> +	}
> +
> +	port->tx_remaining = xmit_size;
> +}
> +

...

Re: [PATCH v3 13/13] tty: serial: qcom-geni-serial: add support for serial engine DMA

[Bartosz Golaszewski]

On Fri, 25 Nov 2022 at 15:37, Srinivas Kandagatla
<srinivas.kandagatla@linaro.org> wrote:
>

<snip>

> >
> > @@ -552,18 +558,11 @@ static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop)
> >
> >   static void handle_rx_uart(struct uart_port *uport, u32 bytes, bool drop)
> >   {
> > -     struct tty_port *tport;
> >       struct qcom_geni_serial_port *port = to_dev_port(uport);
> > -     u32 num_bytes_pw = port->tx_fifo_width / BITS_PER_BYTE;
> > -     u32 words = ALIGN(bytes, num_bytes_pw) / num_bytes_pw;
> > +     struct tty_port *tport = &uport->state->port;
> >       int ret;
> >
> > -     tport = &uport->state->port;
> > -     ioread32_rep(uport->membase + SE_GENI_RX_FIFOn, port->rx_fifo, words);
> > -     if (drop)
> > -             return;
> > -
>
> Are we removing FIFO support for uart?
>
> It it not a overhead to use dma for small transfers that are less than
> fifo size?
>

You made me think about it but no - while I haven't measured it yet, I
don't think it's worth the code complexity behind it. The i2c driver
doesn't do it this way for short transfers either. If you insist I can
test it and come forward with numbers but unless we encounter a
real-life example of the need for lots of very short reads/writes in
short succession, I don't think we should overcomplicate this.

>
> > -     ret = tty_insert_flip_string(tport, port->rx_fifo, bytes);
> > +     ret = tty_insert_flip_string(tport, port->rx_buf, bytes);
> >       if (ret != bytes) {
> >               dev_err(uport->dev, "%s:Unable to push data ret %d_bytes %d\n",
> >                               __func__, ret, bytes);
> > @@ -578,7 +577,70 @@ static unsigned int qcom_geni_serial_tx_empty(struct uart_port *uport)
> >       return !readl(uport->membase + SE_GENI_TX_FIFO_STATUS);
> >   }
> >
> > -static void qcom_geni_serial_start_tx(struct uart_port *uport)
> > +static void qcom_geni_serial_stop_tx_dma(struct uart_port *uport)
> > +{
> > +     struct qcom_geni_serial_port *port = to_dev_port(uport);
> > +     bool done;
>
> -->
> > +     u32 status;
> ...
> > +
> > +     status = readl(uport->membase + SE_GENI_STATUS);
> > +     if (!(status & M_GENI_CMD_ACTIVE))
> > +             return;
> <---
>
> this code snippet is repeating more than few times in the patches, looks
> like it could be made to a inline helper.
>

Makes sense.

>
> > +
> > +     if (port->rx_dma_addr) {
> > +             geni_se_tx_dma_unprep(&port->se, port->tx_dma_addr,
> > +                                   port->tx_remaining);
> > +             port->tx_dma_addr = (dma_addr_t)NULL;
> > +             port->tx_remaining = 0;
> > +     }
> > +
> > +     m_irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN);
> > +     writel(m_irq_en, uport->membase + SE_GENI_M_IRQ_EN);
> > +     geni_se_cancel_m_cmd(&port->se);
> > +
> > +     done = qcom_geni_serial_poll_bit(uport, SE_GENI_S_IRQ_STATUS,
> > +                                      S_CMD_CANCEL_EN, true);
> > +     if (!done) {
> > +             geni_se_abort_m_cmd(&port->se);
> > +             qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS,
> > +                                       M_CMD_ABORT_EN, true);
>
> return is not checked, there are few more such instances in the patch.
>

Yes, but this is an error path. What would I do if the cancel failed
to go through and then the abort failed as well? I can at best emit an
error message.

> > +             writel(M_CMD_ABORT_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
> > +     }
> > +
> > +     writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR);
> > +}
> > +
> > +static void qcom_geni_serial_start_tx_dma(struct uart_port *uport)
> > +{
> > +     struct qcom_geni_serial_port *port = to_dev_port(uport);
> > +     struct circ_buf *xmit = &uport->state->xmit;
> > +     unsigned int xmit_size;
> > +     int ret;
> > +
> > +     if (port->tx_dma_addr)
> > +             return;
> Is this condition actually possible?
>

It should never happen but I wanted to be sure. Maybe a BUG_ON() or
WARN_ON() would be better?

>
> > +
> > +     xmit_size = uart_circ_chars_pending(xmit);
> > +     if (xmit_size < WAKEUP_CHARS)
> > +             uart_write_wakeup(uport);
> > +
> > +     xmit_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
> > +
> > +     qcom_geni_serial_setup_tx(uport, xmit_size);
> > +
> > +     ret = geni_se_tx_dma_prep(&port->se, &xmit->buf[xmit->tail],
> > +                               xmit_size, &port->tx_dma_addr);
> > +     if (ret) {
> > +             dev_err(uport->dev, "unable to start TX SE DMA: %d\n", ret);
> > +             qcom_geni_serial_stop_tx_dma(uport);
> > +             return;
> > +     }
> > +
> > +     port->tx_remaining = xmit_size;
> > +}
> > +
>
> ...

Bart

Re: [PATCH v3 13/13] tty: serial: qcom-geni-serial: add support for serial engine DMA

[Bartosz Golaszewski]

On Fri, Nov 25, 2022 at 3:37 PM Srinivas Kandagatla
<srinivas.kandagatla@linaro.org> wrote:
>

[snip]

> > +
> > +static void qcom_geni_serial_start_tx_dma(struct uart_port *uport)
> > +{
> > +     struct qcom_geni_serial_port *port = to_dev_port(uport);
> > +     struct circ_buf *xmit = &uport->state->xmit;
> > +     unsigned int xmit_size;
> > +     int ret;
> > +
> > +     if (port->tx_dma_addr)
> > +             return;
> Is this condition actually possible?
>

So it turns out, it's possible that the subsystem calls start_tx when
this is already set but the main engine is not yet in active state (so
we can't simply test that bit). This needs to stay then.

Bart