From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756130AbbAWQM6 (ORCPT ); Fri, 23 Jan 2015 11:12:58 -0500 Received: from mail-la0-f52.google.com ([209.85.215.52]:41287 "EHLO mail-la0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755847AbbAWQJJ (ORCPT ); Fri, 23 Jan 2015 11:09:09 -0500 From: Ricardo Ribalda Delgado To: Mark Brown , Michal Simek , =?UTF-8?q?S=C3=B6ren=20Brinkmann?= , linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Ricardo Ribalda Delgado Subject: [PATCH 09/18] spi/xilinx: Do not inhibit transmission in polling mode Date: Fri, 23 Jan 2015 17:08:41 +0100 Message-Id: <1422029330-10971-10-git-send-email-ricardo.ribalda@gmail.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1422029330-10971-1-git-send-email-ricardo.ribalda@gmail.com> References: <1422029330-10971-1-git-send-email-ricardo.ribalda@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 8a28cab..a70cb91 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