From: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
To: "Mark Brown" <broonie@kernel.org>,
"Michal Simek" <michal.simek@xilinx.com>,
"Sören Brinkmann" <soren.brinkmann@xilinx.com>,
linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Subject: [PATCH v2 06/15] spi/xilinx: Do not inhibit transmission in polling mode
Date: Wed, 28 Jan 2015 13:23:45 +0100 [thread overview]
Message-ID: <1422447834-23116-7-git-send-email-ricardo.ribalda@gmail.com> (raw)
In-Reply-To: <1422447834-23116-1-git-send-email-ricardo.ribalda@gmail.com>
When no irq is used, there is no need to inhibit the transmission for
every transaction. This inhibition was implemented to avoid a race
condition with the irq handler.
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
drivers/spi/spi-xilinx.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index f21e857..6656b2c 100644
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -163,6 +163,7 @@ static void xspi_rx32(struct xilinx_spi *xspi)
static void xspi_init_hw(struct xilinx_spi *xspi)
{
void __iomem *regs_base = xspi->regs;
+ u32 inhibit;
/* Reset the SPI device */
xspi->write_fn(XIPIF_V123B_RESET_MASK,
@@ -173,16 +174,19 @@ static void xspi_init_hw(struct xilinx_spi *xspi)
xspi->write_fn(XSPI_INTR_TX_EMPTY,
regs_base + XIPIF_V123B_IIER_OFFSET);
/* Enable the global IPIF interrupt */
- if (xspi->irq >= 0)
+ if (xspi->irq >= 0) {
xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
regs_base + XIPIF_V123B_DGIER_OFFSET);
- else
+ inhibit = XSPI_CR_TRANS_INHIBIT;
+ } else {
xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
+ inhibit = 0;
+ }
/* Deselect the slave on the SPI bus */
xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
/* Disable the transmitter, enable Manual Slave Select Assertion,
* put SPI controller into master mode, and enable it */
- xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
+ xspi->write_fn(inhibit | XSPI_CR_MANUAL_SSELECT |
XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |
XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET);
}
@@ -252,7 +256,7 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
reinit_completion(&xspi->done);
while (xspi->remaining_bytes) {
- u16 cr;
+ u16 cr = 0;
int n_words;
n_words = (xspi->remaining_bytes * 8) / xspi->bits_per_word;
@@ -263,13 +267,13 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
/* Start the transfer by not inhibiting the transmitter any
* longer
*/
- cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
- ~XSPI_CR_TRANS_INHIBIT;
- xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
- if (xspi->irq >= 0)
+ if (xspi->irq >= 0) {
+ cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
+ ~XSPI_CR_TRANS_INHIBIT;
+ xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
wait_for_completion(&xspi->done);
- else
+ } else
while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) &
XSPI_SR_TX_EMPTY_MASK))
;
@@ -279,7 +283,8 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
* transmitter while the Isr refills the transmit register/FIFO,
* or make sure it is stopped if we're done.
*/
- xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+ if (xspi->irq >= 0)
+ xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
xspi->regs + XSPI_CR_OFFSET);
/* Read out all the data from the Rx FIFO */
--
2.1.4
next prev parent reply other threads:[~2015-01-29 1:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-28 12:23 [PATCH v2 00/15] spi/xilinx: Speed-up Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 01/15] spi/xilinx: Simplify spi_fill_tx_fifo Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 02/15] spi/xilinx: Leave the IRQ always enabled Ricardo Ribalda Delgado
2015-01-28 19:38 ` Mark Brown
2015-01-28 12:23 ` [PATCH v2 03/15] spi/xilinx: Code cleanup Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 04/15] spi/xilinx: Use cached value of register Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 05/15] spi/xilinx: Support cores with no interrupt Ricardo Ribalda Delgado
2015-01-28 12:23 ` Ricardo Ribalda Delgado [this message]
2015-01-28 12:23 ` [PATCH v2 07/15] spi/xilinx: Support for spi mode CS_HIGH Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 08/15] spi/xilinx: Remove rx_fn and tx_fn pointer Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 09/15] spi/xilinx: Make spi_tx and spi_rx simmetric Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 10/15] spi/xilinx: Convert remainding_bytes in remaining words Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 11/15] spi/xilinx: Convert bits_per_word in bytes_per_word Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 12/15] spi/xilinx: Remove iowrite/ioread wrappers Ricardo Ribalda Delgado
2015-01-30 6:13 ` Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 13/15] spi/xilinx: Remove remaining_words driver data variable Ricardo Ribalda Delgado
2015-01-28 12:23 ` [PATCH v2 14/15] spi/xilinx: Check number of slaves range Ricardo Ribalda Delgado
2015-01-28 19:40 ` Mark Brown
2015-01-28 12:23 ` [PATCH v2 15/15] spi/xilinx: Use polling mode on small transfers Ricardo Ribalda Delgado
2015-01-28 19:43 ` [PATCH v2 00/15] spi/xilinx: Speed-up Mark Brown
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