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sdio_uart: Use kfifo instead of the messy circ stuff
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Revised patch to use the new kfifo API. This replaces the one that was dropped
from -next due to collisions with the kfifo API changes.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Alan Cox authored and Greg Kroah-Hartman committed Mar 2, 2010
1 parent 6a2c7ea commit 8b197a5
Showing 1 changed file with 30 additions and 63 deletions.
93 changes: 30 additions & 63 deletions drivers/mmc/card/sdio_uart.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@
#include <linux/gfp.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/kfifo.h>

#include <linux/mmc/core.h>
#include <linux/mmc/card.h>
Expand All @@ -47,19 +48,9 @@
#define UART_NR 8 /* Number of UARTs this driver can handle */


#define UART_XMIT_SIZE PAGE_SIZE
#define FIFO_SIZE PAGE_SIZE
#define WAKEUP_CHARS 256

#define circ_empty(circ) ((circ)->head == (circ)->tail)
#define circ_clear(circ) ((circ)->head = (circ)->tail = 0)

#define circ_chars_pending(circ) \
(CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))

#define circ_chars_free(circ) \
(CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))


struct uart_icount {
__u32 cts;
__u32 dsr;
Expand All @@ -82,7 +73,7 @@ struct sdio_uart_port {
struct mutex func_lock;
struct task_struct *in_sdio_uart_irq;
unsigned int regs_offset;
struct circ_buf xmit;
struct kfifo xmit_fifo;
spinlock_t write_lock;
struct uart_icount icount;
unsigned int uartclk;
Expand All @@ -105,6 +96,8 @@ static int sdio_uart_add_port(struct sdio_uart_port *port)
kref_init(&port->kref);
mutex_init(&port->func_lock);
spin_lock_init(&port->write_lock);
if (kfifo_alloc(&port->xmit_fifo, FIFO_SIZE, GFP_KERNEL))
return -ENOMEM;

spin_lock(&sdio_uart_table_lock);
for (index = 0; index < UART_NR; index++) {
Expand Down Expand Up @@ -140,6 +133,7 @@ static void sdio_uart_port_destroy(struct kref *kref)
{
struct sdio_uart_port *port =
container_of(kref, struct sdio_uart_port, kref);
kfifo_free(&port->xmit_fifo);
kfree(port);
}

Expand Down Expand Up @@ -456,9 +450,11 @@ static void sdio_uart_receive_chars(struct sdio_uart_port *port,

static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
{
struct circ_buf *xmit = &port->xmit;
struct kfifo *xmit = &port->xmit_fifo;
int count;
struct tty_struct *tty;
u8 iobuf[16];
int len;

if (port->x_char) {
sdio_out(port, UART_TX, port->x_char);
Expand All @@ -469,27 +465,25 @@ static void sdio_uart_transmit_chars(struct sdio_uart_port *port)

tty = tty_port_tty_get(&port->port);

if (tty == NULL || circ_empty(xmit) ||
if (tty == NULL || !kfifo_len(xmit) ||
tty->stopped || tty->hw_stopped) {
sdio_uart_stop_tx(port);
tty_kref_put(tty);
return;
}

count = 16;
do {
sdio_out(port, UART_TX, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
len = kfifo_out_locked(xmit, iobuf, 16, &port->write_lock);
for (count = 0; count < len; count++) {
sdio_out(port, UART_TX, iobuf[count]);
port->icount.tx++;
if (circ_empty(xmit))
break;
} while (--count > 0);
}

if (circ_chars_pending(xmit) < WAKEUP_CHARS)
len = kfifo_len(xmit);
if (len < WAKEUP_CHARS) {
tty_wakeup(tty);

if (circ_empty(xmit))
sdio_uart_stop_tx(port);
if (len == 0)
sdio_uart_stop_tx(port);
}
tty_kref_put(tty);
}

Expand Down Expand Up @@ -632,7 +626,6 @@ static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
{
struct sdio_uart_port *port =
container_of(tport, struct sdio_uart_port, port);
unsigned long page;
int ret;

/*
Expand All @@ -641,22 +634,17 @@ static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
*/
set_bit(TTY_IO_ERROR, &tty->flags);

/* Initialise and allocate the transmit buffer. */
page = __get_free_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
port->xmit.buf = (unsigned char *)page;
circ_clear(&port->xmit);
kfifo_reset(&port->xmit_fifo);

ret = sdio_uart_claim_func(port);
if (ret)
goto err1;
return ret;
ret = sdio_enable_func(port->func);
if (ret)
goto err2;
goto err1;
ret = sdio_claim_irq(port->func, sdio_uart_irq);
if (ret)
goto err3;
goto err2;

/*
* Clear the FIFO buffers and disable them.
Expand Down Expand Up @@ -700,12 +688,10 @@ static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
sdio_uart_release_func(port);
return 0;

err3:
sdio_disable_func(port->func);
err2:
sdio_uart_release_func(port);
sdio_disable_func(port->func);
err1:
free_page((unsigned long)port->xmit.buf);
sdio_uart_release_func(port);
return ret;
}

Expand All @@ -727,7 +713,7 @@ static void sdio_uart_shutdown(struct tty_port *tport)

ret = sdio_uart_claim_func(port);
if (ret)
goto skip;
return;

sdio_uart_stop_rx(port);

Expand All @@ -749,10 +735,6 @@ static void sdio_uart_shutdown(struct tty_port *tport)
sdio_disable_func(port->func);

sdio_uart_release_func(port);

skip:
/* Free the transmit buffer page. */
free_page((unsigned long)port->xmit.buf);
}

/**
Expand Down Expand Up @@ -822,27 +804,12 @@ static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf,
int count)
{
struct sdio_uart_port *port = tty->driver_data;
struct circ_buf *circ = &port->xmit;
int c, ret = 0;
int ret;

if (!port->func)
return -ENODEV;

spin_lock(&port->write_lock);
while (1) {
c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
if (count < c)
c = count;
if (c <= 0)
break;
memcpy(circ->buf + circ->head, buf, c);
circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
buf += c;
count -= c;
ret += c;
}
spin_unlock(&port->write_lock);

ret = kfifo_in_locked(&port->xmit_fifo, buf, count, &port->write_lock);
if (!(port->ier & UART_IER_THRI)) {
int err = sdio_uart_claim_func(port);
if (!err) {
Expand All @@ -859,13 +826,13 @@ static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf,
static int sdio_uart_write_room(struct tty_struct *tty)
{
struct sdio_uart_port *port = tty->driver_data;
return port ? circ_chars_free(&port->xmit) : 0;
return FIFO_SIZE - kfifo_len(&port->xmit_fifo);
}

static int sdio_uart_chars_in_buffer(struct tty_struct *tty)
{
struct sdio_uart_port *port = tty->driver_data;
return port ? circ_chars_pending(&port->xmit) : 0;
return kfifo_len(&port->xmit_fifo);
}

static void sdio_uart_send_xchar(struct tty_struct *tty, char ch)
Expand Down

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