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Date: Fri, 2 Nov 2007 10:38:29 +0800
From: Bryan Wu <bryan.wu@...log.com>
To: dbrownell@...rs.sourceforge.net, akpm@...ux-foundation.org
Cc: spi-devel-general@...ts.sourceforge.net,
linux-kernel@...r.kernel.org, Bryan Wu <bryan.wu@...log.com>
Subject: [PATCH 1/4] Blackfin SPI driver: use cpu_relax() to replace continue in while busywait
Signed-off-by: Bryan Wu <bryan.wu@...log.com>
---
drivers/spi/spi_bfin5xx.c | 78 ++++++++++++++++++++++----------------------
1 files changed, 39 insertions(+), 39 deletions(-)
diff --git a/drivers/spi/spi_bfin5xx.c b/drivers/spi/spi_bfin5xx.c
index 83c866d..fc0c374 100644
--- a/drivers/spi/spi_bfin5xx.c
+++ b/drivers/spi/spi_bfin5xx.c
@@ -186,7 +186,7 @@ static int flush(struct driver_data *drv_data)
/* wait for stop and clear stat */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF) && limit--)
- continue;
+ cpu_relax();
write_STAT(drv_data, BIT_STAT_CLR);
@@ -262,7 +262,7 @@ static void null_writer(struct driver_data *drv_data)
while (drv_data->tx < drv_data->tx_end) {
write_TDBR(drv_data, 0);
while ((read_STAT(drv_data) & BIT_STAT_TXS))
- continue;
+ cpu_relax();
drv_data->tx += n_bytes;
}
}
@@ -274,7 +274,7 @@ static void null_reader(struct driver_data *drv_data)
while (drv_data->rx < drv_data->rx_end) {
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
dummy_read(drv_data);
drv_data->rx += n_bytes;
}
@@ -287,12 +287,12 @@ static void u8_writer(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
while (drv_data->tx < drv_data->tx_end) {
write_TDBR(drv_data, (*(u8 *) (drv_data->tx)));
while (read_STAT(drv_data) & BIT_STAT_TXS)
- continue;
+ cpu_relax();
++drv_data->tx;
}
}
@@ -303,14 +303,14 @@ static void u8_cs_chg_writer(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
while (drv_data->tx < drv_data->tx_end) {
cs_active(drv_data, chip);
write_TDBR(drv_data, (*(u8 *) (drv_data->tx)));
while (read_STAT(drv_data) & BIT_STAT_TXS)
- continue;
+ cpu_relax();
cs_deactive(drv_data, chip);
@@ -325,7 +325,7 @@ static void u8_reader(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* clear TDBR buffer before read(else it will be shifted out) */
write_TDBR(drv_data, 0xFFFF);
@@ -334,13 +334,13 @@ static void u8_reader(struct driver_data *drv_data)
while (drv_data->rx < drv_data->rx_end - 1) {
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u8 *) (drv_data->rx) = read_RDBR(drv_data);
++drv_data->rx;
}
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u8 *) (drv_data->rx) = read_SHAW(drv_data);
++drv_data->rx;
}
@@ -351,7 +351,7 @@ static void u8_cs_chg_reader(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* clear TDBR buffer before read(else it will be shifted out) */
write_TDBR(drv_data, 0xFFFF);
@@ -363,7 +363,7 @@ static void u8_cs_chg_reader(struct driver_data *drv_data)
cs_deactive(drv_data, chip);
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
cs_active(drv_data, chip);
*(u8 *) (drv_data->rx) = read_RDBR(drv_data);
++drv_data->rx;
@@ -371,7 +371,7 @@ static void u8_cs_chg_reader(struct driver_data *drv_data)
cs_deactive(drv_data, chip);
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u8 *) (drv_data->rx) = read_SHAW(drv_data);
++drv_data->rx;
}
@@ -380,15 +380,15 @@ static void u8_duplex(struct driver_data *drv_data)
{
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* in duplex mode, clk is triggered by writing of TDBR */
while (drv_data->rx < drv_data->rx_end) {
write_TDBR(drv_data, (*(u8 *) (drv_data->tx)));
while (read_STAT(drv_data) & BIT_STAT_TXS)
- continue;
+ cpu_relax();
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u8 *) (drv_data->rx) = read_RDBR(drv_data);
++drv_data->rx;
++drv_data->tx;
@@ -401,16 +401,16 @@ static void u8_cs_chg_duplex(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
while (drv_data->rx < drv_data->rx_end) {
cs_active(drv_data, chip);
write_TDBR(drv_data, (*(u8 *) (drv_data->tx)));
while (read_STAT(drv_data) & BIT_STAT_TXS)
- continue;
+ cpu_relax();
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u8 *) (drv_data->rx) = read_RDBR(drv_data);
cs_deactive(drv_data, chip);
@@ -427,12 +427,12 @@ static void u16_writer(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
while (drv_data->tx < drv_data->tx_end) {
write_TDBR(drv_data, (*(u16 *) (drv_data->tx)));
while ((read_STAT(drv_data) & BIT_STAT_TXS))
- continue;
+ cpu_relax();
drv_data->tx += 2;
}
}
@@ -443,14 +443,14 @@ static void u16_cs_chg_writer(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
while (drv_data->tx < drv_data->tx_end) {
cs_active(drv_data, chip);
write_TDBR(drv_data, (*(u16 *) (drv_data->tx)));
while ((read_STAT(drv_data) & BIT_STAT_TXS))
- continue;
+ cpu_relax();
cs_deactive(drv_data, chip);
@@ -465,7 +465,7 @@ static void u16_reader(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* clear TDBR buffer before read(else it will be shifted out) */
write_TDBR(drv_data, 0xFFFF);
@@ -474,13 +474,13 @@ static void u16_reader(struct driver_data *drv_data)
while (drv_data->rx < (drv_data->rx_end - 2)) {
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u16 *) (drv_data->rx) = read_RDBR(drv_data);
drv_data->rx += 2;
}
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u16 *) (drv_data->rx) = read_SHAW(drv_data);
drv_data->rx += 2;
}
@@ -491,7 +491,7 @@ static void u16_cs_chg_reader(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* clear TDBR buffer before read(else it will be shifted out) */
write_TDBR(drv_data, 0xFFFF);
@@ -503,7 +503,7 @@ static void u16_cs_chg_reader(struct driver_data *drv_data)
cs_deactive(drv_data, chip);
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
cs_active(drv_data, chip);
*(u16 *) (drv_data->rx) = read_RDBR(drv_data);
drv_data->rx += 2;
@@ -511,7 +511,7 @@ static void u16_cs_chg_reader(struct driver_data *drv_data)
cs_deactive(drv_data, chip);
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u16 *) (drv_data->rx) = read_SHAW(drv_data);
drv_data->rx += 2;
}
@@ -520,15 +520,15 @@ static void u16_duplex(struct driver_data *drv_data)
{
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* in duplex mode, clk is triggered by writing of TDBR */
while (drv_data->tx < drv_data->tx_end) {
write_TDBR(drv_data, (*(u16 *) (drv_data->tx)));
while (read_STAT(drv_data) & BIT_STAT_TXS)
- continue;
+ cpu_relax();
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u16 *) (drv_data->rx) = read_RDBR(drv_data);
drv_data->rx += 2;
drv_data->tx += 2;
@@ -541,16 +541,16 @@ static void u16_cs_chg_duplex(struct driver_data *drv_data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
while (drv_data->tx < drv_data->tx_end) {
cs_active(drv_data, chip);
write_TDBR(drv_data, (*(u16 *) (drv_data->tx)));
while (read_STAT(drv_data) & BIT_STAT_TXS)
- continue;
+ cpu_relax();
while (!(read_STAT(drv_data) & BIT_STAT_RXS))
- continue;
+ cpu_relax();
*(u16 *) (drv_data->rx) = read_RDBR(drv_data);
cs_deactive(drv_data, chip);
@@ -624,7 +624,7 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
/* Wait for DMA to complete */
while (get_dma_curr_irqstat(drv_data->dma_channel) & DMA_RUN)
- continue;
+ cpu_relax();
/*
* wait for the last transaction shifted out. HRM states:
@@ -635,11 +635,11 @@ static irqreturn_t dma_irq_handler(int irq, void *dev_id)
if (drv_data->tx != NULL) {
while ((read_STAT(drv_data) & TXS) ||
(read_STAT(drv_data) & TXS))
- continue;
+ cpu_relax();
}
while (!(read_STAT(drv_data) & SPIF))
- continue;
+ cpu_relax();
msg->actual_length += drv_data->len_in_bytes;
@@ -783,7 +783,7 @@ static void pump_transfers(unsigned long data)
/* poll for SPI completion before start */
while (!(read_STAT(drv_data) & BIT_STAT_SPIF))
- continue;
+ cpu_relax();
/* dirty hack for autobuffer DMA mode */
if (drv_data->tx_dma == 0xFFFF) {
--
1.5.3.4
-
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