[PATCH v4 0/2] Add tracepoints support for Qualcomm GENI Serial drivers

[PATCH v4 0/2] Add tracepoints support for Qualcomm GENI Serial drivers

[Praveen Talari]

Add tracepoints to the Qualcomm GENI (Generic Interface) serial driver.
These trace events enable runtime debugging and performance analysis of
UART operations.

The trace events cover UART termios configuration, clock setup, manual
control state, interrupt status, and actual transmitted/received data in
hexadecimal format.

Usage examples:

Enable all serial traces:
  echo 1 > /sys/kernel/debug/tracing/events/qcom_geni_serial/enable
  cat /sys/kernel/debug/tracing/trace_pipe

Example trace output:

2517.938432: geni_serial_clk_cfg: a94000.serial: desired_rate=1843200
     clk_rate=7372800 clk_div=4 clk_idx=0
2517.938753: geni_serial_irq: a94000.serial: m_irq=0x88800000
     s_irq=0x08000111 dma_tx=0x00000000 dma_rx=0x00000000
2517.938803: geni_serial_set_termios: a94000.serial: baud=115200 bpc=8
     tx_trans=0x00000002 tx_par=0x00000000 rx_trans=0x00000000
rx_par=0x00000000 stop=0
2517.938807: geni_serial_set_mctrl: a94000.serial: mctrl=0x8006
     uart_manual_rfr=0x00000000
2517.938818: geni_serial_get_mctrl: a94000.serial: mctrl=0x0160
     geni_ios=0x00000001
2517.939165: geni_serial_irq: a94000.serial: m_irq=0x00400000
     s_irq=0x00000000 dma_tx=0x00000000 dma_rx=0x00000000
2517.939592: geni_serial_tx_data: a94000.serial: tx_len=8 data=61 62 63
     64 65 66 67 68
2517.940610: geni_serial_irq: a94000.serial: m_irq=0x00000001
     s_irq=0x00000000 dma_tx=0x00000003 dma_rx=0x00000000
2517.942174: geni_serial_irq: a94000.serial: m_irq=0x08000000
     s_irq=0x08000100 dma_tx=0x00000000 dma_rx=0x00000003
2517.942323: geni_serial_rx_data: a94000.serial: rx_len=8 data=61 62 63
     64 65 66 67 68
2517.942680: geni_serial_set_mctrl: a94000.serial: mctrl=0x8000
     uart_manual_rfr=0x80000002

Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
---
Changes in v4:
- Rebased patch(02/02) on latest linux-next.
- Link to v3: https://lore.kernel.org/all/20260518-add-tracepoints-for-qcom-geni-serial-v3-0-b4addb151376@oss.qualcomm.com

Changes in v3:
- Removed \n from geni_serial_tx_data and geni_serial_rx_data events.
- Resolved aligment issues in geni_serial_data, geni_serial_tx_data and
  geni_serial_rx_data events.
- Link to v2: https://lore.kernel.org/r/20260512-add-tracepoints-for-qcom-geni-serial-v2-0-a5726421b3af@oss.qualcomm.com

Changes in v2:
- removed multiple trace events for TX/RX events, instead used
  DECLARE_EVENT_CLASS and DEFINE_EVENT.
- Link to v1: https://lore.kernel.org/r/20260506-add-tracepoints-for-qcom-geni-serial-v1-0-544b22612e08@oss.qualcomm.com

To: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Jiri Slaby <jirislaby@kernel.org>
To: konrad.dybcio@oss.qualcomm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-kernel@vger.kernel.org
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Cc: mukesh.savaliya@oss.qualcomm.com
Cc: aniket.randive@oss.qualcomm.com
Cc: chandana.chiluveru@oss.qualcomm.com

---
Praveen Talari (2):
      serial: qcom-geni: trace: Add tracepoint support for Qualcomm GENI serial
      serial: qcom-geni: Add tracepoints for Qualcomm GENI serial driver

 drivers/tty/serial/qcom_geni_serial.c   |  27 +++++-
 include/trace/events/qcom_geni_serial.h | 164 ++++++++++++++++++++++++++++++++
 2 files changed, 187 insertions(+), 4 deletions(-)
---
base-commit: d387b06f7c15b4639244ad66b4b0900c6a02b430
change-id: 20260427-add-tracepoints-for-qcom-geni-serial-948777218b7b

Best regards,
--  
Praveen Talari <praveen.talari@oss.qualcomm.com>

[PATCH v4 1/2] serial: qcom-geni: trace: Add tracepoint support for Qualcomm GENI serial

[Praveen Talari]

Add tracepoint support to the Qualcomm GENI serial driver to provide
runtime visibility into driver behavior without requiring invasive debug
patches.

The trace events cover UART termios configuration, clock setup, modem
control state, interrupt status, and TX/RX data, making it easier to
diagnose communication issues in the field.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
---
v2->v3:
- Removed \n from geni_serial_tx_data and geni_serial_rx_data events.
- Resolved aligment issues in geni_serial_data, geni_serial_tx_data and
  geni_serial_rx_data events.

v1->v2:
- Removed multiple TX/RX trace events, instead used
  DECLARE_EVENT_CLASS and DEFINE_EVENT.
---
 include/trace/events/qcom_geni_serial.h | 164 ++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)

diff --git a/include/trace/events/qcom_geni_serial.h b/include/trace/events/qcom_geni_serial.h
new file mode 100644
index 000000000000..417ec01f9fc8
--- /dev/null
+++ b/include/trace/events/qcom_geni_serial.h
@@ -0,0 +1,164 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM qcom_geni_serial
+
+#if !defined(_TRACE_QCOM_GENI_SERIAL_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_QCOM_GENI_SERIAL_H
+
+#include <linux/device.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(geni_serial_set_termios,
+	    TP_PROTO(struct device *dev, unsigned int baud,
+		     unsigned int bits_per_char, u32 tx_trans_cfg,
+		     u32 tx_parity_cfg, u32 rx_trans_cfg,
+		     u32 rx_parity_cfg, u32 stop_bit_len),
+	    TP_ARGS(dev, baud, bits_per_char, tx_trans_cfg, tx_parity_cfg,
+		    rx_trans_cfg, rx_parity_cfg, stop_bit_len),
+
+	    TP_STRUCT__entry(__string(name, dev_name(dev))
+			     __field(unsigned int, baud)
+			     __field(unsigned int, bits_per_char)
+			     __field(u32, tx_trans_cfg)
+			     __field(u32, tx_parity_cfg)
+			     __field(u32, rx_trans_cfg)
+			     __field(u32, rx_parity_cfg)
+			     __field(u32, stop_bit_len)
+	    ),
+
+	    TP_fast_assign(__assign_str(name);
+			   __entry->baud = baud;
+			   __entry->bits_per_char = bits_per_char;
+			   __entry->tx_trans_cfg = tx_trans_cfg;
+			   __entry->tx_parity_cfg = tx_parity_cfg;
+			   __entry->rx_trans_cfg = rx_trans_cfg;
+			   __entry->rx_parity_cfg = rx_parity_cfg;
+			   __entry->stop_bit_len = stop_bit_len;
+	    ),
+
+	    TP_printk("%s: baud=%u bpc=%u tx_trans=0x%08x tx_par=0x%08x rx_trans=0x%08x rx_par=0x%08x stop=%u",
+		      __get_str(name), __entry->baud, __entry->bits_per_char,
+		      __entry->tx_trans_cfg, __entry->tx_parity_cfg,
+		      __entry->rx_trans_cfg, __entry->rx_parity_cfg,
+		      __entry->stop_bit_len)
+);
+
+TRACE_EVENT(geni_serial_clk_cfg,
+	    TP_PROTO(struct device *dev, unsigned int desired_rate,
+		     unsigned long clk_rate, unsigned int clk_div,
+		     unsigned int clk_idx),
+	    TP_ARGS(dev, desired_rate, clk_rate, clk_div, clk_idx),
+
+	    TP_STRUCT__entry(__string(name, dev_name(dev))
+			     __field(unsigned int, desired_rate)
+			     __field(unsigned long, clk_rate)
+			     __field(unsigned int, clk_div)
+			     __field(unsigned int, clk_idx)
+	    ),
+
+	    TP_fast_assign(__assign_str(name);
+			   __entry->desired_rate = desired_rate;
+			   __entry->clk_rate = clk_rate;
+			   __entry->clk_div = clk_div;
+			   __entry->clk_idx = clk_idx;
+	    ),
+
+	    TP_printk("%s: desired_rate=%u clk_rate=%lu clk_div=%u clk_idx=%u",
+		      __get_str(name), __entry->desired_rate, __entry->clk_rate,
+		      __entry->clk_div, __entry->clk_idx)
+);
+
+TRACE_EVENT(geni_serial_irq,
+	    TP_PROTO(struct device *dev, u32 m_irq, u32 s_irq,
+		     u32 dma_tx, u32 dma_rx),
+	    TP_ARGS(dev, m_irq, s_irq, dma_tx, dma_rx),
+
+	    TP_STRUCT__entry(__string(name, dev_name(dev))
+			     __field(u32, m_irq)
+			     __field(u32, s_irq)
+			     __field(u32, dma_tx)
+			     __field(u32, dma_rx)
+	    ),
+
+	    TP_fast_assign(__assign_str(name);
+			   __entry->m_irq = m_irq;
+			   __entry->s_irq = s_irq;
+			   __entry->dma_tx = dma_tx;
+			   __entry->dma_rx = dma_rx;
+	    ),
+
+	    TP_printk("%s: m_irq=0x%08x s_irq=0x%08x dma_tx=0x%08x dma_rx=0x%08x",
+		      __get_str(name), __entry->m_irq, __entry->s_irq,
+		      __entry->dma_tx, __entry->dma_rx)
+);
+
+DECLARE_EVENT_CLASS(geni_serial_data,
+		    TP_PROTO(struct device *dev, const u8 *buf, unsigned int len),
+		    TP_ARGS(dev, buf, len),
+
+		    TP_STRUCT__entry(__string(name, dev_name(dev))
+				     __field(unsigned int, len)
+				     __dynamic_array(u8, data, len)
+		    ),
+
+		    TP_fast_assign(__assign_str(name);
+				   __entry->len = len;
+				   memcpy(__get_dynamic_array(data), buf, len);
+		    ),
+
+		    TP_printk("%s: len=%u data=%s",
+			      __get_str(name), __entry->len,
+			      __print_hex(__get_dynamic_array(data), __entry->len))
+);
+
+DEFINE_EVENT(geni_serial_data, geni_serial_tx_data,
+	     TP_PROTO(struct device *dev, const u8 *buf, unsigned int len),
+	     TP_ARGS(dev, buf, len)
+);
+
+DEFINE_EVENT(geni_serial_data, geni_serial_rx_data,
+	     TP_PROTO(struct device *dev, const u8 *buf, unsigned int len),
+	     TP_ARGS(dev, buf, len)
+);
+
+TRACE_EVENT(geni_serial_set_mctrl,
+	    TP_PROTO(struct device *dev, unsigned int mctrl,
+		     u32 uart_manual_rfr),
+	    TP_ARGS(dev, mctrl, uart_manual_rfr),
+
+	    TP_STRUCT__entry(__string(name, dev_name(dev))
+			     __field(unsigned int, mctrl)
+			     __field(u32, uart_manual_rfr)
+	    ),
+
+	    TP_fast_assign(__assign_str(name);
+			   __entry->mctrl = mctrl;
+			   __entry->uart_manual_rfr = uart_manual_rfr;
+	    ),
+
+	    TP_printk("%s: mctrl=0x%04x uart_manual_rfr=0x%08x",
+		      __get_str(name), __entry->mctrl, __entry->uart_manual_rfr)
+);
+
+TRACE_EVENT(geni_serial_get_mctrl,
+	    TP_PROTO(struct device *dev, unsigned int mctrl, u32 geni_ios),
+	    TP_ARGS(dev, mctrl, geni_ios),
+
+	    TP_STRUCT__entry(__string(name, dev_name(dev))
+			     __field(unsigned int, mctrl)
+			     __field(u32, geni_ios)
+	    ),
+
+	    TP_fast_assign(__assign_str(name);
+			   __entry->mctrl = mctrl;
+			   __entry->geni_ios = geni_ios;
+	    ),
+
+	    TP_printk("%s: mctrl=0x%04x geni_ios=0x%08x",
+		      __get_str(name), __entry->mctrl, __entry->geni_ios)
+);
+
+#endif /* _TRACE_QCOM_GENI_SERIAL_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

-- 
2.34.1

[PATCH v4 2/2] serial: qcom-geni: Add tracepoints for Qualcomm GENI serial driver

[Praveen Talari]

Add tracing to the Qualcomm GENI serial driver to improve runtime
observability.

Trace hooks are added at key points including termios and clock
configuration, manual control get/set, interrupt handling, and data
TX/RX paths.

Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Praveen Talari <praveen.talari@oss.qualcomm.com>
---
v2->v3:
- Updated commit text(removed example as it was available on cover
  letter).
---
 drivers/tty/serial/qcom_geni_serial.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index d81b539cff7f..4b62e58d4918 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -7,6 +7,9 @@
 /* Disable MMIO tracing to prevent excessive logging of unwanted MMIO traces */
 #define __DISABLE_TRACE_MMIO__
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/qcom_geni_serial.h>
+
 #include <linux/clk.h>
 #include <linux/console.h>
 #include <linux/io.h>
@@ -226,7 +229,7 @@ static void qcom_geni_serial_config_port(struct uart_port *uport, int cfg_flags)
 static unsigned int qcom_geni_serial_get_mctrl(struct uart_port *uport)
 {
 	unsigned int mctrl = TIOCM_DSR | TIOCM_CAR;
-	u32 geni_ios;
+	u32 geni_ios = 0;
 
 	if (uart_console(uport)) {
 		mctrl |= TIOCM_CTS;
@@ -236,6 +239,8 @@ static unsigned int qcom_geni_serial_get_mctrl(struct uart_port *uport)
 			mctrl |= TIOCM_CTS;
 	}
 
+	trace_geni_serial_get_mctrl(uport->dev, mctrl, geni_ios);
+
 	return mctrl;
 }
 
@@ -254,6 +259,8 @@ static void qcom_geni_serial_set_mctrl(struct uart_port *uport,
 	if (port->manual_flow && !(mctrl & TIOCM_RTS) && !uport->suspended)
 		uart_manual_rfr = UART_MANUAL_RFR_EN | UART_RFR_NOT_READY;
 	writel(uart_manual_rfr, uport->membase + SE_UART_MANUAL_RFR);
+
+	trace_geni_serial_set_mctrl(uport->dev, mctrl, uart_manual_rfr);
 }
 
 static const char *qcom_geni_serial_get_type(struct uart_port *uport)
@@ -684,6 +691,8 @@ static void qcom_geni_serial_start_tx_dma(struct uart_port *uport)
 	xmit_size = kfifo_out_linear_ptr(&tport->xmit_fifo, &tail,
 			UART_XMIT_SIZE);
 
+	trace_geni_serial_tx_data(uport->dev, tail, xmit_size);
+
 	qcom_geni_set_rs485_mode(uport, SER_RS485_RTS_ON_SEND);
 
 	qcom_geni_serial_setup_tx(uport, xmit_size);
@@ -910,8 +919,10 @@ static void qcom_geni_serial_handle_rx_dma(struct uart_port *uport, bool drop)
 		return;
 	}
 
-	if (!drop)
+	if (!drop) {
+		trace_geni_serial_rx_data(uport->dev, port->rx_buf, rx_in);
 		handle_rx_uart(uport, rx_in);
+	}
 
 	ret = geni_se_rx_dma_prep(&port->se, port->rx_buf,
 				  DMA_RX_BUF_SIZE,
@@ -1082,6 +1093,10 @@ static irqreturn_t qcom_geni_serial_isr(int isr, void *dev)
 	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);
+
+	trace_geni_serial_irq(uport->dev, m_irq_status, s_irq_status,
+			      dma_tx_status, dma_rx_status);
+
 	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);
@@ -1294,8 +1309,8 @@ static int geni_serial_set_rate(struct uart_port *uport, unsigned int baud)
 		return -EINVAL;
 	}
 
-	dev_dbg(port->se.dev, "desired_rate = %u, clk_rate = %lu, clk_div = %u, clk_idx = %u\n",
-		baud * sampling_rate, clk_rate, clk_div, clk_idx);
+	trace_geni_serial_clk_cfg(uport->dev, baud * sampling_rate, clk_rate,
+				  clk_div, clk_idx);
 
 	uport->uartclk = clk_rate;
 	port->clk_rate = clk_rate;
@@ -1455,6 +1470,10 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport,
 	writel(bits_per_char, uport->membase + SE_UART_TX_WORD_LEN);
 	writel(bits_per_char, uport->membase + SE_UART_RX_WORD_LEN);
 	writel(stop_bit_len, uport->membase + SE_UART_TX_STOP_BIT_LEN);
+
+	trace_geni_serial_set_termios(uport->dev, baud, bits_per_char,
+				      tx_trans_cfg, tx_parity_cfg, rx_trans_cfg,
+				      rx_parity_cfg, stop_bit_len);
 }
 
 #ifdef CONFIG_SERIAL_QCOM_GENI_CONSOLE

-- 
2.34.1

Re: [PATCH v4 1/2] serial: qcom-geni: trace: Add tracepoint support for Qualcomm GENI serial

[Steven Rostedt]

On Tue, 26 May 2026 23:07:39 +0530
Praveen Talari <praveen.talari@oss.qualcomm.com> wrote:

> +DECLARE_EVENT_CLASS(geni_serial_data,
> +		    TP_PROTO(struct device *dev, const u8 *buf, unsigned int len),
> +		    TP_ARGS(dev, buf, len),
> +
> +		    TP_STRUCT__entry(__string(name, dev_name(dev))
> +				     __field(unsigned int, len)
> +				     __dynamic_array(u8, data, len)
> +		    ),
> +
> +		    TP_fast_assign(__assign_str(name);
> +				   __entry->len = len;
> +				   memcpy(__get_dynamic_array(data), buf, len);
> +		    ),
> +
> +		    TP_printk("%s: len=%u data=%s",
> +			      __get_str(name), __entry->len,
> +			      __print_hex(__get_dynamic_array(data), __entry->len))
> +);

No need to save the length of the dynamic array in __entry->len because
it's already saved in the metadata of the dynamic array that is stored
on the buffer. Instead you can have:

DECLARE_EVENT_CLASS(geni_serial_data,
		    TP_PROTO(struct device *dev, const u8 *buf, unsigned int len),
		    TP_ARGS(dev, buf, len),

		    TP_STRUCT__entry(__string(name, dev_name(dev))
				     __dynamic_array(u8, data, len)
		    ),

		    TP_fast_assign(__assign_str(name);
				   memcpy(__get_dynamic_array(data), buf, len);
		    ),

		    TP_printk("%s: len=%u data=%s",
			      __get_str(name), __entry->len,
			      __print_hex(__get_dynamic_array(data),
					__get_dynamic_array_len(data)))
);

That will save you 4 bytes per event on the ring buffer. And a few
cycles not having to store the redundant information.

-- Steve