linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
* mpc52xx_uart and rs485
@ 2008-08-14  9:23 Sinisa Denic
  2008-09-24 14:20 ` Grant Likely
  0 siblings, 1 reply; 3+ messages in thread
From: Sinisa Denic @ 2008-08-14  9:23 UTC (permalink / raw)
  To: linuxppc-dev

>From bf050adbc092043c1ba6e43373563bb761bb2e40 Mon Sep 17 00:00:00 2001
From: Sinisa Denic <sinisa.denic@abs-cs.com>
Date: Wed, 13 Aug 2008 15:57:52 +0200
Subject: [PATCH] mpc52xx_uart RS485 support added

Hi Wolfgang and others, 
below is patch for mpc52xx_usrt.c which add software rs485 support to 
this driver.
It has worked for me and if you think it is good enough it might be 
useful for someone else.
Regards, 
Sinisa Denic
System and software  engineer
tel: +381(0)112016142
ABS Control Systems
bul.Zorana Djindjica 8a
Belgrade,Serbia
---
 drivers/serial/mpc52xx_uart.c |   47 +++++++++++++++++++++++++++++++++
+-------
 1 files changed, 39 insertions(+), 8 deletions(-)

diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
index 7a3625f..38b2751 100644
--- a/drivers/serial/mpc52xx_uart.c
+++ b/drivers/serial/mpc52xx_uart.c
@@ -62,7 +62,7 @@
  * by the bootloader or in the platform init code.
  */
 
-#undef DEBUG
+//#undef DEBUG
 
 #include <linux/device.h>
 #include <linux/module.h>
@@ -142,11 +142,13 @@ struct psc_ops {
 	int		(*rx_rdy)(struct uart_port *port);
 	int		(*tx_rdy)(struct uart_port *port);
 	int		(*tx_empty)(struct uart_port *port);
+	int		(*tx_empty_enabled)(struct uart_port *port);
 	void		(*stop_rx)(struct uart_port *port);
 	void		(*start_tx)(struct uart_port *port);
 	void		(*stop_tx)(struct uart_port *port);
 	void		(*rx_clr_irq)(struct uart_port *port);
 	void		(*tx_clr_irq)(struct uart_port *port);
+	void		(*tx_empty_clr_irq)(struct uart_port *port);
 	void		(*write_char)(struct uart_port *port, unsigned 
char c);
 	unsigned char	(*read_char)(struct uart_port *port);
 	void		(*cw_disable_ints)(struct uart_port *port);
@@ -169,7 +171,7 @@ static void mpc52xx_psc_fifo_init(struct uart_port 
*port)
 	out_8(&fifo->tfcntl, 0x07);
 	out_be16(&fifo->tfalarm, 0x80);
 
-	port->read_status_mask |= MPC52xx_PSC_IMR_RXRDY | 
MPC52xx_PSC_IMR_TXRDY;
+	port->read_status_mask |= MPC52xx_PSC_IMR_RXRDY | 
MPC52xx_PSC_IMR_TXRDY | MPC52xx_PSC_IMR_TXEMP; 
 	out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
 }
 
@@ -200,6 +202,13 @@ static int mpc52xx_psc_tx_rdy(struct uart_port *port)
 	    & MPC52xx_PSC_IMR_TXRDY;
 }
 
+static int mpc52xx_psc_tx_empty_enabled(struct uart_port *port)
+{
+	return in_be16(&PSC(port)->mpc52xx_psc_isr)
+	    & port->read_status_mask
+	    & MPC52xx_PSC_IMR_TXEMP;
+}
+
 static int mpc52xx_psc_tx_empty(struct uart_port *port)
 {
 	return in_be16(&PSC(port)->mpc52xx_psc_status)
@@ -209,6 +218,7 @@ static int mpc52xx_psc_tx_empty(struct uart_port 
*port)
 static void mpc52xx_psc_start_tx(struct uart_port *port)
 {
 	port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
+	port->read_status_mask |= MPC52xx_PSC_IMR_TXEMP;
 	out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
 }
 
@@ -232,6 +242,11 @@ static void mpc52xx_psc_tx_clr_irq(struct uart_port 
*port)
 {
 }
 
+static void mpc52xx_psc_tx_empty_clr_irq(struct uart_port *port)
+{
+	port->read_status_mask &= ~MPC52xx_PSC_IMR_TXEMP;
+	out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
+}
 static void mpc52xx_psc_write_char(struct uart_port *port, unsigned char 
c)
 {
 	out_8(&PSC(port)->mpc52xx_psc_buffer_8, c);
@@ -275,11 +290,13 @@ static struct psc_ops mpc52xx_psc_ops = {
 	.rx_rdy = mpc52xx_psc_rx_rdy,
 	.tx_rdy = mpc52xx_psc_tx_rdy,
 	.tx_empty = mpc52xx_psc_tx_empty,
+	.tx_empty_enabled = mpc52xx_psc_tx_empty_enabled,
 	.stop_rx = mpc52xx_psc_stop_rx,
 	.start_tx = mpc52xx_psc_start_tx,
 	.stop_tx = mpc52xx_psc_stop_tx,
 	.rx_clr_irq = mpc52xx_psc_rx_clr_irq,
 	.tx_clr_irq = mpc52xx_psc_tx_clr_irq,
+	.tx_empty_clr_irq = mpc52xx_psc_tx_empty_clr_irq,
 	.write_char = mpc52xx_psc_write_char,
 	.read_char = mpc52xx_psc_read_char,
 	.cw_disable_ints = mpc52xx_psc_cw_disable_ints,
@@ -583,7 +600,7 @@ mpc52xx_uart_set_termios(struct uart_port *port, 
struct ktermios *new,
 
 
 	mr2 = 0;
-
+	
 	if (new->c_cflag & CSTOPB)
 		mr2 |= MPC52xx_PSC_MODE_TWO_STOP;
 	else
@@ -591,7 +608,6 @@ mpc52xx_uart_set_termios(struct uart_port *port, 
struct ktermios *new,
 			MPC52xx_PSC_MODE_ONE_STOP_5_BITS :
 			MPC52xx_PSC_MODE_ONE_STOP;
 
-
 	baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16);
 	quot = uart_get_divisor(port, baud);
 	ctr = quot & 0xffff;
@@ -735,7 +751,7 @@ mpc52xx_uart_int_rx_chars(struct uart_port *port)
 	struct tty_struct *tty = port->info->tty;
 	unsigned char ch, flag;
 	unsigned short status;
-
+	//printk("Int. citanje...\n");
 	/* While we can read, do so ! */
 	while (psc_ops->raw_rx_rdy(port)) {
 		/* Get the char */
@@ -792,7 +808,9 @@ static inline int
 mpc52xx_uart_int_tx_chars(struct uart_port *port)
 {
 	struct circ_buf *xmit = &port->info->xmit;
+	out_8(&PSC(port)->op1,1);
 
+//	printk("Int. slanje...\n");
 	/* Process out of band chars */
 	if (port->x_char) {
 		psc_ops->write_char(port, port->x_char);
@@ -812,8 +830,10 @@ mpc52xx_uart_int_tx_chars(struct uart_port *port)
 		psc_ops->write_char(port, xmit->buf[xmit->tail]);
 		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 		port->icount.tx++;
-		if (uart_circ_empty(xmit))
+		if (uart_circ_empty(xmit)){
+//		printk("Uart circular buffer is empty!!\n");
 			break;
+			}
 	}
 
 	/* Wake up */
@@ -828,7 +848,15 @@ mpc52xx_uart_int_tx_chars(struct uart_port *port)
 
 	return 1;
 }
-
+static inline int
+mpc52xx_uart_int_tx_empty(struct uart_port *port)
+{
+	out_8(&PSC(port)->op0,1);
+	port->read_status_mask &= ~MPC52xx_PSC_IMR_TXEMP;
+	out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
+//printk("tx_empty_interrupt!\n");
+	return 0;
+}
 static irqreturn_t
 mpc52xx_uart_int(int irq, void *dev_id)
 {
@@ -850,7 +878,10 @@ mpc52xx_uart_int(int irq, void *dev_id)
 		psc_ops->tx_clr_irq(port);
 		if (psc_ops->tx_rdy(port))
 			keepgoing |= mpc52xx_uart_int_tx_chars(port);
-
+		if (psc_ops->tx_empty_enabled(port)){
+			keepgoing |= mpc52xx_uart_int_tx_empty(port);
+//			psc_ops->tx_empty_clr_irq(port);
+		}
 		/* Limit number of iteration */
 		if (!(--pass))
 			keepgoing = 0;
-- 
1.5.4.5

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: mpc52xx_uart and rs485
  2008-08-14  9:23 mpc52xx_uart and rs485 Sinisa Denic
@ 2008-09-24 14:20 ` Grant Likely
  2008-09-26  7:11   ` Wolfram Sang
  0 siblings, 1 reply; 3+ messages in thread
From: Grant Likely @ 2008-09-24 14:20 UTC (permalink / raw)
  To: Sinisa Denic; +Cc: linuxppc-dev

On Thu, Aug 14, 2008 at 11:23:49AM +0200, Sinisa Denic wrote:
> From bf050adbc092043c1ba6e43373563bb761bb2e40 Mon Sep 17 00:00:00 2001
> From: Sinisa Denic <sinisa.denic@abs-cs.com>
> Date: Wed, 13 Aug 2008 15:57:52 +0200
> Subject: [PATCH] mpc52xx_uart RS485 support added
> 
> Hi Wolfgang and others, 
> below is patch for mpc52xx_usrt.c which add software rs485 support to 
> this driver.
> It has worked for me and if you think it is good enough it might be 
> useful for someone else.

Thanks for the patch.  I've made a number of comments below and it
appears that your mail client has damaged the patch.  Can you please
respin after addressing the comments.  When you repost, please include a
technical description of what you have done and why.

Thanks,
g.

> ---
>  drivers/serial/mpc52xx_uart.c |   47 +++++++++++++++++++++++++++++++++
> +-------
>  1 files changed, 39 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/serial/mpc52xx_uart.c b/drivers/serial/mpc52xx_uart.c
> index 7a3625f..38b2751 100644
> --- a/drivers/serial/mpc52xx_uart.c
> +++ b/drivers/serial/mpc52xx_uart.c
> @@ -62,7 +62,7 @@
>   * by the bootloader or in the platform init code.
>   */
>  
> -#undef DEBUG
> +//#undef DEBUG

Unrelated changes; please remove.

>  
>  #include <linux/device.h>
>  #include <linux/module.h>
> @@ -142,11 +142,13 @@ struct psc_ops {
>  	int		(*rx_rdy)(struct uart_port *port);
>  	int		(*tx_rdy)(struct uart_port *port);
>  	int		(*tx_empty)(struct uart_port *port);
> +	int		(*tx_empty_enabled)(struct uart_port *port);
>  	void		(*stop_rx)(struct uart_port *port);
>  	void		(*start_tx)(struct uart_port *port);
>  	void		(*stop_tx)(struct uart_port *port);
>  	void		(*rx_clr_irq)(struct uart_port *port);
>  	void		(*tx_clr_irq)(struct uart_port *port);
> +	void		(*tx_empty_clr_irq)(struct uart_port *port);
>  	void		(*write_char)(struct uart_port *port, unsigned 
> char c);
>  	unsigned char	(*read_char)(struct uart_port *port);
>  	void		(*cw_disable_ints)(struct uart_port *port);
> @@ -169,7 +171,7 @@ static void mpc52xx_psc_fifo_init(struct uart_port 
> *port)
>  	out_8(&fifo->tfcntl, 0x07);
>  	out_be16(&fifo->tfalarm, 0x80);
>  
> -	port->read_status_mask |= MPC52xx_PSC_IMR_RXRDY | 
> MPC52xx_PSC_IMR_TXRDY;
> +	port->read_status_mask |= MPC52xx_PSC_IMR_RXRDY | 
> MPC52xx_PSC_IMR_TXRDY | MPC52xx_PSC_IMR_TXEMP; 

Patch was line wrapped here by your mailer

>  	out_be16(&psc->mpc52xx_psc_imr, port->read_status_mask);
>  }
>  
> @@ -200,6 +202,13 @@ static int mpc52xx_psc_tx_rdy(struct uart_port *port)
>  	    & MPC52xx_PSC_IMR_TXRDY;
>  }
>  
> +static int mpc52xx_psc_tx_empty_enabled(struct uart_port *port)
> +{
> +	return in_be16(&PSC(port)->mpc52xx_psc_isr)
> +	    & port->read_status_mask
> +	    & MPC52xx_PSC_IMR_TXEMP;
> +}
> +
>  static int mpc52xx_psc_tx_empty(struct uart_port *port)
>  {
>  	return in_be16(&PSC(port)->mpc52xx_psc_status)
> @@ -209,6 +218,7 @@ static int mpc52xx_psc_tx_empty(struct uart_port 
> *port)
>  static void mpc52xx_psc_start_tx(struct uart_port *port)
>  {
>  	port->read_status_mask |= MPC52xx_PSC_IMR_TXRDY;
> +	port->read_status_mask |= MPC52xx_PSC_IMR_TXEMP;

You're enabling the TXEMP interrupts unconditionally, regardless of
whether or not rs485 is used.  This adds performance impact to
non-rs485 users.

>  	out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
>  }
>  
> @@ -232,6 +242,11 @@ static void mpc52xx_psc_tx_clr_irq(struct uart_port 
> *port)
>  {
>  }
>  
> +static void mpc52xx_psc_tx_empty_clr_irq(struct uart_port *port)
> +{
> +	port->read_status_mask &= ~MPC52xx_PSC_IMR_TXEMP;
> +	out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
> +}
>  static void mpc52xx_psc_write_char(struct uart_port *port, unsigned char 
> c)
>  {
>  	out_8(&PSC(port)->mpc52xx_psc_buffer_8, c);
> @@ -275,11 +290,13 @@ static struct psc_ops mpc52xx_psc_ops = {
>  	.rx_rdy = mpc52xx_psc_rx_rdy,
>  	.tx_rdy = mpc52xx_psc_tx_rdy,
>  	.tx_empty = mpc52xx_psc_tx_empty,
> +	.tx_empty_enabled = mpc52xx_psc_tx_empty_enabled,
>  	.stop_rx = mpc52xx_psc_stop_rx,
>  	.start_tx = mpc52xx_psc_start_tx,
>  	.stop_tx = mpc52xx_psc_stop_tx,
>  	.rx_clr_irq = mpc52xx_psc_rx_clr_irq,
>  	.tx_clr_irq = mpc52xx_psc_tx_clr_irq,
> +	.tx_empty_clr_irq = mpc52xx_psc_tx_empty_clr_irq,
>  	.write_char = mpc52xx_psc_write_char,
>  	.read_char = mpc52xx_psc_read_char,
>  	.cw_disable_ints = mpc52xx_psc_cw_disable_ints,
> @@ -583,7 +600,7 @@ mpc52xx_uart_set_termios(struct uart_port *port, 
> struct ktermios *new,
>  
>  
>  	mr2 = 0;
> -
> +	

Unrelated whitespace change; please omit from patch

>  	if (new->c_cflag & CSTOPB)
>  		mr2 |= MPC52xx_PSC_MODE_TWO_STOP;
>  	else
> @@ -591,7 +608,6 @@ mpc52xx_uart_set_termios(struct uart_port *port, 
> struct ktermios *new,
>  			MPC52xx_PSC_MODE_ONE_STOP_5_BITS :
>  			MPC52xx_PSC_MODE_ONE_STOP;
>  
> -

Ditto

>  	baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16);
>  	quot = uart_get_divisor(port, baud);
>  	ctr = quot & 0xffff;
> @@ -735,7 +751,7 @@ mpc52xx_uart_int_rx_chars(struct uart_port *port)
>  	struct tty_struct *tty = port->info->tty;
>  	unsigned char ch, flag;
>  	unsigned short status;
> -
> +	//printk("Int. citanje...\n");

Remove

>  	/* While we can read, do so ! */
>  	while (psc_ops->raw_rx_rdy(port)) {
>  		/* Get the char */
> @@ -792,7 +808,9 @@ static inline int
>  mpc52xx_uart_int_tx_chars(struct uart_port *port)
>  {
>  	struct circ_buf *xmit = &port->info->xmit;
> +	out_8(&PSC(port)->op1,1);
>  
> +//	printk("Int. slanje...\n");

Remove

>  	/* Process out of band chars */
>  	if (port->x_char) {
>  		psc_ops->write_char(port, port->x_char);
> @@ -812,8 +830,10 @@ mpc52xx_uart_int_tx_chars(struct uart_port *port)
>  		psc_ops->write_char(port, xmit->buf[xmit->tail]);
>  		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
>  		port->icount.tx++;
> -		if (uart_circ_empty(xmit))
> +		if (uart_circ_empty(xmit)){
> +//		printk("Uart circular buffer is empty!!\n");
>  			break;
> +			}

Remove

>  	}
>  
>  	/* Wake up */
> @@ -828,7 +848,15 @@ mpc52xx_uart_int_tx_chars(struct uart_port *port)
>  
>  	return 1;
>  }
> -
> +static inline int
> +mpc52xx_uart_int_tx_empty(struct uart_port *port)
> +{
> +	out_8(&PSC(port)->op0,1);
> +	port->read_status_mask &= ~MPC52xx_PSC_IMR_TXEMP;
> +	out_be16(&PSC(port)->mpc52xx_psc_imr, port->read_status_mask);
> +//printk("tx_empty_interrupt!\n");

Remove debug line.

> +	return 0;
> +}
>  static irqreturn_t
>  mpc52xx_uart_int(int irq, void *dev_id)
>  {
> @@ -850,7 +878,10 @@ mpc52xx_uart_int(int irq, void *dev_id)
>  		psc_ops->tx_clr_irq(port);
>  		if (psc_ops->tx_rdy(port))
>  			keepgoing |= mpc52xx_uart_int_tx_chars(port);
> -
> +		if (psc_ops->tx_empty_enabled(port)){
> +			keepgoing |= mpc52xx_uart_int_tx_empty(port);
> +//			psc_ops->tx_empty_clr_irq(port);
> +		}

It isn't clear what this code is doing.
mpc52xx_uart_int_tx_empty() only ever returns 0, so it will not change
the value of keepgoing.  The call to mpc52xx_uart_int_tx_empty() will
clear the TXEMP mask, but you need to describe why it is done.

>  		/* Limit number of iteration */
>  		if (!(--pass))
>  			keepgoing = 0;
> -- 
> 1.5.4.5
> 
> 
> 
> 
> 
> 
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: mpc52xx_uart and rs485
  2008-09-24 14:20 ` Grant Likely
@ 2008-09-26  7:11   ` Wolfram Sang
  0 siblings, 0 replies; 3+ messages in thread
From: Wolfram Sang @ 2008-09-26  7:11 UTC (permalink / raw)
  To: Grant Likely; +Cc: Sinisa Denic, linuxppc-dev

[-- Attachment #1: Type: text/plain, Size: 973 bytes --]

Hello,

On Wed, Sep 24, 2008 at 08:20:16AM -0600, Grant Likely wrote:

> > Hi Wolfgang and others, 
> > below is patch for mpc52xx_usrt.c which add software rs485 support to 
> > this driver.
> > It has worked for me and if you think it is good enough it might be 
> > useful for someone else.
> 
> Thanks for the patch.  I've made a number of comments below and it
> appears that your mail client has damaged the patch.  Can you please
> respin after addressing the comments.  When you repost, please include a
> technical description of what you have done and why.

And please add linux-serial as cc then. I recently read some criticism
about software RS485 (http://article.gmane.org/gmane.linux.serial/2573).
I don't know if these apply to this patch, but it would be nice to have
it sorted out IMHO.

All the best,

   Wolfram

-- 
  Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 189 bytes --]

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2008-09-26  7:11 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-08-14  9:23 mpc52xx_uart and rs485 Sinisa Denic
2008-09-24 14:20 ` Grant Likely
2008-09-26  7:11   ` Wolfram Sang

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).