sdio_uart: Use kfifo instead of the messy circ stuff

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>

diff --git a/drivers/mmc/card/sdio_uart.c b/drivers/mmc/card/sdio_uart.c
index f537555..3fab78b 100644 (file)
--- a/drivers/mmc/card/sdio_uart.c
+++ b/drivers/mmc/card/sdio_uart.c
@@ -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>
@@ -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;
@@ -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;
@@ -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++) {
@@ -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);
 }
 
@@ -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);
@@ -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);
 }
 
@@ -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;
 
        /*
@@ -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.
@@ -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;
 }
 
@@ -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);
 
@@ -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);
 }
 
 /**
@@ -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) {
@@ -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)