mpc52xx_uart and rs485
Grant Likely
grant.likely at secretlab.ca
Thu Sep 25 00:20:16 EST 2008
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 at 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
>
>
>
>
>
>
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