[PATCH v2 0/6] serial: uartps:

[PATCH v2 0/6] serial: uartps:

[Michal Simek]

Hi,

This patchset is fixing several issues reported by checkpatch but also
major number handling for multiple allocated ports. For more information
please look at the first patch which describes more details.

When this patchset is applied driver only reports one checkpatch warning
which should be fixed via console.h first.
include/linux/console.h:147:    void    (*write)(struct console *, const char *, unsigned);

WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
+				    unsigned n)

Thanks,
Michal

v1
 https://lkml.org/lkml/2019/6/10/186
 https://lkml.org/lkml/2019/6/10/187


Changes in v2:
- Fix typo in subject line
- Swap patches compare to previous series
- Add Fixes tag
- Split patch from v1
- Fixes second S_IRUGO usage
- Add Fixes tag
- Split patch from v1
- Add Fixes tag
- Split patch from v1
- Add Fixes tag
- Split patch from v1
- Add Fixes tag
- Split patch from v1
- Add Fixes tag

Nava kishore Manne (5):
  serial: uartps: Use octal permission for module_param()
  serial: uartps: Fix multiple line dereference
  serial: uartps: Fix long line over 80 chars
  serial: uartps: Do not add a trailing semicolon to macro
  serial: uartps: Remove useless return from cdns_uart_poll_put_char

Shubhrajyoti Datta (1):
  serial: uartps: Use the same dynamic major number for all ports

 drivers/tty/serial/xilinx_uartps.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

-- 
2.17.1

[PATCH v2 1/6] serial: uartps: Use the same dynamic major number for all ports

[Michal Simek]

From: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>

Let kernel to find out major number dynamically for the first device and
then reuse it for other instances.
This fixes the issue that each uart is registered with a
different major number.

After the patch:
crw-------    1 root     root      253,   0 Jun 10 08:31 /dev/ttyPS0
crw--w----    1 root     root      253,   1 Jan  1  1970 /dev/ttyPS1

Fixes: 024ca329bfb9 ("serial: uartps: Register own uart console and driver structures")
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v2:
- Fix typo in subject line
- Swap patches compare to previous series
- Add Fixes tag

 drivers/tty/serial/xilinx_uartps.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 605354fd60b1..9dcc4d855ddd 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -29,12 +29,12 @@
 
 #define CDNS_UART_TTY_NAME	"ttyPS"
 #define CDNS_UART_NAME		"xuartps"
-#define CDNS_UART_MAJOR		0	/* use dynamic node allocation */
 #define CDNS_UART_FIFO_SIZE	64	/* FIFO size */
 #define CDNS_UART_REGISTER_SPACE	0x1000
 
 /* Rx Trigger level */
 static int rx_trigger_level = 56;
+static int uartps_major;
 module_param(rx_trigger_level, uint, S_IRUGO);
 MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes");
 
@@ -1517,7 +1517,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
 	cdns_uart_uart_driver->owner = THIS_MODULE;
 	cdns_uart_uart_driver->driver_name = driver_name;
 	cdns_uart_uart_driver->dev_name	= CDNS_UART_TTY_NAME;
-	cdns_uart_uart_driver->major = CDNS_UART_MAJOR;
+	cdns_uart_uart_driver->major = uartps_major;
 	cdns_uart_uart_driver->minor = cdns_uart_data->id;
 	cdns_uart_uart_driver->nr = 1;
 
@@ -1546,6 +1546,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
 		goto err_out_id;
 	}
 
+	uartps_major = cdns_uart_uart_driver->tty_driver->major;
 	cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver;
 
 	/*
-- 
2.17.1

[PATCH v2 2/6] serial: uartps: Use octal permission for module_param()

[Michal Simek]

From: Nava kishore Manne <nava.manne@xilinx.com>

Octal permission is preffered compare to symbolic one.

This patch fixes checkpatch warnings:
Symbolic permissions 'S_IRUGO' are not preferred. Consider using octal
permissions '0444'.

Fixes: 85baf542d54e ("tty: xuartps: support 64 byte FIFO size")
Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v2:
- Split patch from v1
- Fixes second S_IRUGO usage
- Add Fixes tag

 drivers/tty/serial/xilinx_uartps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 9dcc4d855ddd..c84db82bdaab 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -35,12 +35,12 @@
 /* Rx Trigger level */
 static int rx_trigger_level = 56;
 static int uartps_major;
-module_param(rx_trigger_level, uint, S_IRUGO);
+module_param(rx_trigger_level, uint, 0444);
 MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes");
 
 /* Rx Timeout */
 static int rx_timeout = 10;
-module_param(rx_timeout, uint, S_IRUGO);
+module_param(rx_timeout, uint, 0444);
 MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255");
 
 /* Register offsets for the UART. */
-- 
2.17.1

[PATCH v2 3/6] serial: uartps: Fix multiple line dereference

[Michal Simek]

From: Nava kishore Manne <nava.manne@xilinx.com>

Trivial patch which fixes this checkpatch warning:
WARNING: Avoid multiple line dereference - prefer 'port->state->xmit.tail'
+				port->state->xmit.buf[port->state->xmit.
+				tail], port->membase + CDNS_UART_FIFO);

Fixes: c8dbdc842d30 ("serial: xuartps: Rewrite the interrupt handling logic")
Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v2:
- Split patch from v1
- Add Fixes tag

 drivers/tty/serial/xilinx_uartps.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index c84db82bdaab..4cd20c036750 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -319,8 +319,8 @@ static void cdns_uart_handle_tx(void *dev_id)
 			 * register.
 			 */
 			writel(
-				port->state->xmit.buf[port->state->xmit.
-				tail], port->membase + CDNS_UART_FIFO);
+				port->state->xmit.buf[port->state->xmit.tail],
+					port->membase + CDNS_UART_FIFO);
 
 			port->icount.tx++;
 
-- 
2.17.1

Re: [PATCH v2 3/6] serial: uartps: Fix multiple line dereference

[Joe Perches]

On Wed, 2019-06-12 at 13:14 +0200, Michal Simek wrote:
> From: Nava kishore Manne <nava.manne@xilinx.com>
> 
> Trivial patch which fixes this checkpatch warning:
> WARNING: Avoid multiple line dereference - prefer 'port->state->xmit.tail'
> +				port->state->xmit.buf[port->state->xmit.
> +				tail], port->membase + CDNS_UART_FIFO);
> 
> Fixes: c8dbdc842d30 ("serial: xuartps: Rewrite the interrupt handling logic")
> Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
> 
> Changes in v2:
> - Split patch from v1
> - Add Fixes tag
> 
>  drivers/tty/serial/xilinx_uartps.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
> index c84db82bdaab..4cd20c036750 100644
> --- a/drivers/tty/serial/xilinx_uartps.c
> +++ b/drivers/tty/serial/xilinx_uartps.c
> @@ -319,8 +319,8 @@ static void cdns_uart_handle_tx(void *dev_id)
>  			 * register.
>  			 */
>  			writel(
> -				port->state->xmit.buf[port->state->xmit.
> -				tail], port->membase + CDNS_UART_FIFO);
> +				port->state->xmit.buf[port->state->xmit.tail],
> +					port->membase + CDNS_UART_FIFO);
>  
>  			port->icount.tx++;

Another way to rewrite this is to use a temporary for
port->state->xmit and also return early on empty to
avoid unnecessary indentation.

Using a temporary can also reduce object size a bit by
removing unnecessary dereferences: (defconfig x86-64)

$ size drivers/tty/serial/xilinx_uartps.o*
   text	   data	    bss	    dec	    hex	filename
  26578	   4632	    320	  31530	   7b2a	drivers/tty/serial/xilinx_uartps.o.new
  26642	   4632	    320	  31594	   7b6a	drivers/tty/serial/xilinx_uartps.o.old

i.e.:

---
 drivers/tty/serial/xilinx_uartps.c | 54 ++++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 29 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 605354fd60b1..09b586aeeca3 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -305,40 +305,36 @@ static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus)
 static void cdns_uart_handle_tx(void *dev_id)
 {
 	struct uart_port *port = (struct uart_port *)dev_id;
+	struct circ_buf *xmit = &port->state->xmit;
 	unsigned int numbytes;
 
-	if (uart_circ_empty(&port->state->xmit)) {
+	if (uart_circ_empty(xmit)) {
 		writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
-	} else {
-		numbytes = port->fifosize;
-		while (numbytes && !uart_circ_empty(&port->state->xmit) &&
-		       !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
-			/*
-			 * Get the data from the UART circular buffer
-			 * and write it to the cdns_uart's TX_FIFO
-			 * register.
-			 */
-			writel(
-				port->state->xmit.buf[port->state->xmit.
-				tail], port->membase + CDNS_UART_FIFO);
-
-			port->icount.tx++;
-
-			/*
-			 * Adjust the tail of the UART buffer and wrap
-			 * the buffer if it reaches limit.
-			 */
-			port->state->xmit.tail =
-				(port->state->xmit.tail + 1) &
-					(UART_XMIT_SIZE - 1);
-
-			numbytes--;
-		}
+		return;
+	}
+
+	numbytes = port->fifosize;
+	while (numbytes && !uart_circ_empty(xmit) &&
+	       !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
+		/*
+		 * Get the data from the UART circular buffer and write it
+		 * to the cdns_uart's TX_FIFO register.
+		 */
+		writel(xmit->buf[xmit->tail], port->membase + CDNS_UART_FIFO);
+
+		port->icount.tx++;
+
+		/*
+		 * Adjust the tail of the UART buffer and wrap the buffer
+		 * if it reaches limit.
+		 */
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 
-		if (uart_circ_chars_pending(
-				&port->state->xmit) < WAKEUP_CHARS)
-			uart_write_wakeup(port);
+		numbytes--;
 	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
 }
 
 /**
 

[PATCH v2 4/6] serial: uartps: Fix long line over 80 chars

[Michal Simek]

From: Nava kishore Manne <nava.manne@xilinx.com>

Trivial patch which fixes one checkpatch warning:
WARNING: line over 80 characters
+		       !(readl(port->membase + CDNS_UART_SR)
			& CDNS_UART_SR_TXFULL)) {

Fixes: c8dbdc842d30 ("serial: xuartps: Rewrite the interrupt handling logic")
Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v2:
- Split patch from v1
- Add Fixes tag

 drivers/tty/serial/xilinx_uartps.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 4cd20c036750..c3949a323815 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -312,7 +312,8 @@ static void cdns_uart_handle_tx(void *dev_id)
 	} else {
 		numbytes = port->fifosize;
 		while (numbytes && !uart_circ_empty(&port->state->xmit) &&
-		       !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) {
+		       !(readl(port->membase + CDNS_UART_SR) &
+						CDNS_UART_SR_TXFULL)) {
 			/*
 			 * Get the data from the UART circular buffer
 			 * and write it to the cdns_uart's TX_FIFO
-- 
2.17.1

[PATCH v2 5/6] serial: uartps: Do not add a trailing semicolon to macro

[Michal Simek]

From: Nava kishore Manne <nava.manne@xilinx.com>

This patch fixes this checkpatch warning:
WARNING: macros should not use a trailing semicolon
+#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
+		clk_rate_change_nb);

Fixes: d9bb3fb12685 ("tty: xuartps: Rebrand driver as Cadence UART")
Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v2:
- Split patch from v1
- Add Fixes tag

Origin patch which introduce this semicolon was
c4b0510cc1571ff44e1 ("tty: xuartps: Dynamically adjust to input frequency
changes")
---
 drivers/tty/serial/xilinx_uartps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index c3949a323815..d4c1ae2ffca6 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -199,7 +199,7 @@ struct cdns_platform_data {
 	u32 quirks;
 };
 #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
-		clk_rate_change_nb);
+		clk_rate_change_nb)
 
 /**
  * cdns_uart_handle_rx - Handle the received bytes along with Rx errors.
-- 
2.17.1

Re: [PATCH v2 5/6] serial: uartps: Do not add a trailing semicolon to macro

[Joe Perches]

On Wed, 2019-06-12 at 13:14 +0200, Michal Simek wrote:
> From: Nava kishore Manne <nava.manne@xilinx.com>
> 
> This patch fixes this checkpatch warning:
> WARNING: macros should not use a trailing semicolon
> +#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
> +		clk_rate_change_nb);
> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
[]
> @@ -199,7 +199,7 @@ struct cdns_platform_data {
>  	u32 quirks;
>  };
>  #define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
> -		clk_rate_change_nb);
> +		clk_rate_change_nb)
>  
>  /**
>   * cdns_uart_handle_rx - Handle the received bytes along with Rx errors.

trivia:

Perhaps this is easier for humans to read with the macro
on two lines like:

#define to_cdns_uart(_nb) \
	container_of(_nb, struct cdns_uart, clk_rate_change_nb)

or just ignore the 80 column limit

#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, clk_rate_change_nb)

or because the macro is only used in one place,
just get rid of it and use container_of directly.
---
 drivers/tty/serial/xilinx_uartps.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 605354fd60b1..ca5cec2b83ce 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -195,11 +195,10 @@ struct cdns_uart {
 	u32			quirks;
 	bool cts_override;
 };
+
 struct cdns_platform_data {
 	u32 quirks;
 };
-#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \
-		clk_rate_change_nb);
 
 /**
  * cdns_uart_handle_rx - Handle the received bytes along with Rx errors.
@@ -489,8 +488,9 @@ static int cdns_uart_clk_notifier_cb(struct notifier_block *nb,
 	int locked = 0;
 	struct clk_notifier_data *ndata = data;
 	unsigned long flags = 0;
-	struct cdns_uart *cdns_uart = to_cdns_uart(nb);
+	struct cdns_uart *cdns_uart;
 
+	cdns_uart = container_of(nb, struct cdns_uart, clk_rate_change_nb);
 	port = cdns_uart->port;
 	if (port->suspended)
 		return NOTIFY_OK;

[PATCH v2 6/6] serial: uartps: Remove useless return from cdns_uart_poll_put_char

[Michal Simek]

From: Nava kishore Manne <nava.manne@xilinx.com>

There is no reason to call return at the end of function which should
return void.

The patch is also remove one checkpatch warning:
WARNING: void function return statements are not generally useful
+	return;
+}

Fixes: 6ee04c6c5488 ("tty: xuartps: Add polled mode support for xuartps")
Signed-off-by: Nava kishore Manne <nava.manne@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

Changes in v2:
- Split patch from v1
- Add Fixes tag

 drivers/tty/serial/xilinx_uartps.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index d4c1ae2ffca6..bcef254fa03c 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1074,8 +1074,6 @@ static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c)
 		cpu_relax();
 
 	spin_unlock_irqrestore(&port->lock, flags);
-
-	return;
 }
 #endif
 
-- 
2.17.1