From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755897AbbAWQJL (ORCPT ); Fri, 23 Jan 2015 11:09:11 -0500 Received: from mail-lb0-f179.google.com ([209.85.217.179]:63133 "EHLO mail-lb0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755536AbbAWQJC (ORCPT ); Fri, 23 Jan 2015 11:09:02 -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 04/18] spi-xilinx: Simplify spi_fill_tx_fifo Date: Fri, 23 Jan 2015 17:08:36 +0100 Message-Id: <1422029330-10971-5-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 Instead of checking the TX_FULL flag for every transaction, find out the size of the buffer at probe time and use it. Signed-off-by: Ricardo Ribalda Delgado --- drivers/spi/spi-xilinx.c | 39 ++++++++++++++++++++++++++------------- 1 file changed, 26 insertions(+), 13 deletions(-) diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c index 416b227..17480a2 100644 --- a/drivers/spi/spi-xilinx.c +++ b/drivers/spi/spi-xilinx.c @@ -88,6 +88,7 @@ struct xilinx_spi { const u8 *tx_ptr; /* pointer in the Rx buffer */ int remaining_bytes; /* the number of bytes left to transfer */ u8 bits_per_word; + int buffer_size; /* buffer size in words */ unsigned int (*read_fn)(void __iomem *); void (*write_fn)(u32, void __iomem *); void (*tx_fn)(struct xilinx_spi *); @@ -221,24 +222,16 @@ static int xilinx_spi_setup_transfer(struct spi_device *spi, return 0; } -static int xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi) +static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi, int n_words) { - u8 sr; - int n_words = 0; + xspi->remaining_bytes -= n_words * xspi->bits_per_word / 8; - /* Fill the Tx FIFO with as many bytes as possible */ - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) { + while (n_words--) if (xspi->tx_ptr) xspi->tx_fn(xspi); else xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); - xspi->remaining_bytes -= xspi->bits_per_word / 8; - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - n_words++; - } - - return n_words; + return; } static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) @@ -265,7 +258,10 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) u16 cr; int n_words; - n_words = xilinx_spi_fill_tx_fifo(xspi); + n_words = (xspi->remaining_bytes * 8) / xspi->bits_per_word; + n_words = min(n_words, xspi->buffer_size); + + xilinx_spi_fill_tx_fifo(xspi, n_words); /* Start the transfer by not inhibiting the transmitter any * longer @@ -322,6 +318,21 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id) return IRQ_HANDLED; } +static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi) +{ + u8 sr; + int n_words = 0; + + /* Fill the Tx FIFO with as many words as possible */ + do { + xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); + sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); + n_words++; + } while (!(sr & XSPI_SR_TX_FULL_MASK)); + + return n_words; +} + static const struct of_device_id xilinx_spi_of_match[] = { { .compatible = "xlnx,xps-spi-2.00.a", }, { .compatible = "xlnx,xps-spi-2.00.b", }, @@ -413,6 +424,8 @@ static int xilinx_spi_probe(struct platform_device *pdev) goto put_master; } + xspi->buffer_size = xilinx_spi_find_buffer_size(xspi); + /* SPI controller initializations */ xspi_init_hw(xspi); -- 2.1.4