From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bryan Wu Subject: [PATCH 1/4] Blackfin SPI driver: use cpu_relax() to replace continue in while busywait Date: Fri, 2 Nov 2007 10:38:29 +0800 Message-ID: <1193971112-7744-2-git-send-email-bryan.wu@analog.com> References: <1193971112-7744-1-git-send-email-bryan.wu@analog.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Bryan Wu , spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Return-path: In-Reply-To: <1193971112-7744-1-git-send-email-bryan.wu-OyLXuOCK7orQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: spi-devel-general-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: linux-spi.vger.kernel.org Signed-off-by: Bryan Wu --- 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 ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/