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Subject[PATCH 08/10] cyclades: push down tty_port_tty_get
Date
Now, the tty is not needed at all places in the ISR. So we can just
request in on demand when really needed.

This cleans TX and RX paths a bit as the indentation level can be
dropped by two now when we also invert the char_count if condition.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
drivers/tty/cyclades.c | 237 ++++++++++++++++++++++++-------------------------
1 file changed, 115 insertions(+), 122 deletions(-)

diff --git a/drivers/tty/cyclades.c b/drivers/tty/cyclades.c
index 42a329b..345bd0e 100644
--- a/drivers/tty/cyclades.c
+++ b/drivers/tty/cyclades.c
@@ -917,7 +917,7 @@ cyz_issue_cmd(struct cyclades_card *cinfo,
return 0;
} /* cyz_issue_cmd */

-static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
+static void cyz_handle_rx(struct cyclades_port *info)
{
struct BUF_CTRL __iomem *buf_ctrl = info->u.cyz.buf_ctrl;
struct cyclades_card *cinfo = info->card;
@@ -940,80 +940,77 @@ static void cyz_handle_rx(struct cyclades_port *info, struct tty_struct *tty)
else
char_count = rx_put - rx_get + rx_bufsize;

- if (char_count) {
+ if (!char_count)
+ return;
+
#ifdef CY_ENABLE_MONITORING
- info->mon.int_count++;
- info->mon.char_count += char_count;
- if (char_count > info->mon.char_max)
- info->mon.char_max = char_count;
- info->mon.char_last = char_count;
+ info->mon.int_count++;
+ info->mon.char_count += char_count;
+ if (char_count > info->mon.char_max)
+ info->mon.char_max = char_count;
+ info->mon.char_last = char_count;
#endif
- if (tty == NULL) {
- /* flush received characters */
- new_rx_get = (new_rx_get + char_count) &
- (rx_bufsize - 1);
- info->rflush_count++;
- } else {
+
#ifdef BLOCKMOVE
- /* we'd like to use memcpy(t, f, n) and memset(s, c, count)
- for performance, but because of buffer boundaries, there
- may be several steps to the operation */
- while (1) {
- len = tty_prepare_flip_string(port, &buf,
- char_count);
- if (!len)
- break;
+ /* we'd like to use memcpy(t, f, n) and memset(s, c, count)
+ for performance, but because of buffer boundaries, there
+ may be several steps to the operation */
+ while (1) {
+ len = tty_prepare_flip_string(port, &buf,
+ char_count);
+ if (!len)
+ break;

- len = min_t(unsigned int, min(len, char_count),
- rx_bufsize - new_rx_get);
+ len = min_t(unsigned int, min(len, char_count),
+ rx_bufsize - new_rx_get);

- memcpy_fromio(buf, cinfo->base_addr +
- rx_bufaddr + new_rx_get, len);
+ memcpy_fromio(buf, cinfo->base_addr +
+ rx_bufaddr + new_rx_get, len);

- new_rx_get = (new_rx_get + len) &
- (rx_bufsize - 1);
- char_count -= len;
- info->icount.rx += len;
- info->idle_stats.recv_bytes += len;
- }
+ new_rx_get = (new_rx_get + len) &
+ (rx_bufsize - 1);
+ char_count -= len;
+ info->icount.rx += len;
+ info->idle_stats.recv_bytes += len;
+ }
#else
- len = tty_buffer_request_room(port, char_count);
- while (len--) {
- data = readb(cinfo->base_addr + rx_bufaddr +
- new_rx_get);
- new_rx_get = (new_rx_get + 1) &
- (rx_bufsize - 1);
- tty_insert_flip_char(port, data, TTY_NORMAL);
- info->idle_stats.recv_bytes++;
- info->icount.rx++;
- }
+ len = tty_buffer_request_room(port, char_count);
+ while (len--) {
+ data = readb(cinfo->base_addr + rx_bufaddr +
+ new_rx_get);
+ new_rx_get = (new_rx_get + 1) &
+ (rx_bufsize - 1);
+ tty_insert_flip_char(port, data, TTY_NORMAL);
+ info->idle_stats.recv_bytes++;
+ info->icount.rx++;
+ }
#endif
#ifdef CONFIG_CYZ_INTR
- /* Recalculate the number of chars in the RX buffer and issue
- a cmd in case it's higher than the RX high water mark */
- rx_put = readl(&buf_ctrl->rx_put);
- if (rx_put >= rx_get)
- char_count = rx_put - rx_get;
- else
- char_count = rx_put - rx_get + rx_bufsize;
- if (char_count >= readl(&buf_ctrl->rx_threshold) &&
- !timer_pending(&cyz_rx_full_timer[
- info->line]))
- mod_timer(&cyz_rx_full_timer[info->line],
- jiffies + 1);
+ /* Recalculate the number of chars in the RX buffer and issue
+ a cmd in case it's higher than the RX high water mark */
+ rx_put = readl(&buf_ctrl->rx_put);
+ if (rx_put >= rx_get)
+ char_count = rx_put - rx_get;
+ else
+ char_count = rx_put - rx_get + rx_bufsize;
+ if (char_count >= readl(&buf_ctrl->rx_threshold) &&
+ !timer_pending(&cyz_rx_full_timer[
+ info->line]))
+ mod_timer(&cyz_rx_full_timer[info->line],
+ jiffies + 1);
#endif
- info->idle_stats.recv_idle = jiffies;
- tty_schedule_flip(&info->port);
- }
- /* Update rx_get */
- cy_writel(&buf_ctrl->rx_get, new_rx_get);
- }
+ info->idle_stats.recv_idle = jiffies;
+ tty_schedule_flip(&info->port);
+
+ /* Update rx_get */
+ cy_writel(&buf_ctrl->rx_get, new_rx_get);
}

-static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
+static void cyz_handle_tx(struct cyclades_port *info)
{
struct BUF_CTRL __iomem *buf_ctrl = info->u.cyz.buf_ctrl;
struct cyclades_card *cinfo = info->card;
+ struct tty_struct *tty;
u8 data;
unsigned int char_count;
#ifdef BLOCKMOVE
@@ -1033,63 +1030,63 @@ static void cyz_handle_tx(struct cyclades_port *info, struct tty_struct *tty)
else
char_count = tx_get - tx_put - 1;

- if (char_count) {
-
- if (tty == NULL)
- goto ztxdone;
+ if (!char_count)
+ return;
+
+ tty = tty_port_tty_get(&info->port);
+ if (tty == NULL)
+ goto ztxdone;

- if (info->x_char) { /* send special char */
- data = info->x_char;
+ if (info->x_char) { /* send special char */
+ data = info->x_char;

- cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
- tx_put = (tx_put + 1) & (tx_bufsize - 1);
- info->x_char = 0;
- char_count--;
- info->icount.tx++;
- }
+ cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
+ tx_put = (tx_put + 1) & (tx_bufsize - 1);
+ info->x_char = 0;
+ char_count--;
+ info->icount.tx++;
+ }
#ifdef BLOCKMOVE
- while (0 < (small_count = min_t(unsigned int,
- tx_bufsize - tx_put, min_t(unsigned int,
- (SERIAL_XMIT_SIZE - info->xmit_tail),
- min_t(unsigned int, info->xmit_cnt,
- char_count))))) {
-
- memcpy_toio((char *)(cinfo->base_addr + tx_bufaddr +
- tx_put),
- &info->port.xmit_buf[info->xmit_tail],
- small_count);
-
- tx_put = (tx_put + small_count) & (tx_bufsize - 1);
- char_count -= small_count;
- info->icount.tx += small_count;
- info->xmit_cnt -= small_count;
- info->xmit_tail = (info->xmit_tail + small_count) &
- (SERIAL_XMIT_SIZE - 1);
- }
+ while (0 < (small_count = min_t(unsigned int,
+ tx_bufsize - tx_put, min_t(unsigned int,
+ (SERIAL_XMIT_SIZE - info->xmit_tail),
+ min_t(unsigned int, info->xmit_cnt,
+ char_count))))) {
+
+ memcpy_toio((char *)(cinfo->base_addr + tx_bufaddr + tx_put),
+ &info->port.xmit_buf[info->xmit_tail],
+ small_count);
+
+ tx_put = (tx_put + small_count) & (tx_bufsize - 1);
+ char_count -= small_count;
+ info->icount.tx += small_count;
+ info->xmit_cnt -= small_count;
+ info->xmit_tail = (info->xmit_tail + small_count) &
+ (SERIAL_XMIT_SIZE - 1);
+ }
#else
- while (info->xmit_cnt && char_count) {
- data = info->port.xmit_buf[info->xmit_tail];
- info->xmit_cnt--;
- info->xmit_tail = (info->xmit_tail + 1) &
- (SERIAL_XMIT_SIZE - 1);
-
- cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
- tx_put = (tx_put + 1) & (tx_bufsize - 1);
- char_count--;
- info->icount.tx++;
- }
+ while (info->xmit_cnt && char_count) {
+ data = info->port.xmit_buf[info->xmit_tail];
+ info->xmit_cnt--;
+ info->xmit_tail = (info->xmit_tail + 1) &
+ (SERIAL_XMIT_SIZE - 1);
+
+ cy_writeb(cinfo->base_addr + tx_bufaddr + tx_put, data);
+ tx_put = (tx_put + 1) & (tx_bufsize - 1);
+ char_count--;
+ info->icount.tx++;
+ }
#endif
- tty_wakeup(tty);
+ tty_wakeup(tty);
+ tty_kref_put(tty);
ztxdone:
- /* Update tx_put */
- cy_writel(&buf_ctrl->tx_put, tx_put);
- }
+ /* Update tx_put */
+ cy_writel(&buf_ctrl->tx_put, tx_put);
}

static void cyz_handle_cmd(struct cyclades_card *cinfo)
{
struct BOARD_CTRL __iomem *board_ctrl = cinfo->board_ctrl;
- struct tty_struct *tty;
struct cyclades_port *info;
__u32 channel, param, fw_ver;
__u8 cmd;
@@ -1102,9 +1099,6 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
special_count = 0;
delta_count = 0;
info = &cinfo->ports[channel];
- tty = tty_port_tty_get(&info->port);
- if (tty == NULL)
- continue;

switch (cmd) {
case C_CM_PR_ERROR:
@@ -1130,8 +1124,14 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
readl(&info->u.cyz.ch_ctrl->rs_status);
if (dcd & C_RS_DCD)
wake_up_interruptible(&info->port.open_wait);
- else
- tty_hangup(tty);
+ else {
+ struct tty_struct *tty;
+ tty = tty_port_tty_get(&info->port);
+ if (tty) {
+ tty_hangup(tty);
+ tty_kref_put(tty);
+ }
+ }
}
break;
case C_CM_MCTS:
@@ -1160,7 +1160,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
printk(KERN_DEBUG "cyz_interrupt: rcvd intr, card %d, "
"port %ld\n", info->card, channel);
#endif
- cyz_handle_rx(info, tty);
+ cyz_handle_rx(info);
break;
case C_CM_TXBEMPTY:
case C_CM_TXLOWWM:
@@ -1170,7 +1170,7 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
printk(KERN_DEBUG "cyz_interrupt: xmit intr, card %d, "
"port %ld\n", info->card, channel);
#endif
- cyz_handle_tx(info, tty);
+ cyz_handle_tx(info);
break;
#endif /* CONFIG_CYZ_INTR */
case C_CM_FATAL:
@@ -1183,7 +1183,6 @@ static void cyz_handle_cmd(struct cyclades_card *cinfo)
wake_up_interruptible(&info->port.delta_msr_wait);
if (special_count)
tty_schedule_flip(&info->port);
- tty_kref_put(tty);
}
}

@@ -1249,17 +1248,11 @@ static void cyz_poll(unsigned long arg)
cyz_handle_cmd(cinfo);

for (port = 0; port < cinfo->nports; port++) {
- struct tty_struct *tty;
-
info = &cinfo->ports[port];
- tty = tty_port_tty_get(&info->port);
- /* OK to pass NULL to the handle functions below.
- They need to drop the data in that case. */

if (!info->throttle)
- cyz_handle_rx(info, tty);
- cyz_handle_tx(info, tty);
- tty_kref_put(tty);
+ cyz_handle_rx(info);
+ cyz_handle_tx(info);
}
/* poll every 'cyz_polling_cycle' period */
expires = jiffies + cyz_polling_cycle;
--
1.8.1



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