From mboxrd@z Thu Jan 1 00:00:00 1970 From: kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org Subject: [PATCH v3 8/8] spi: bcm2835: move to spi-core methods translate_message and can_dma Date: Mon, 14 Dec 2015 15:20:25 +0000 Message-ID: <1450106426-2277-9-git-send-email-kernel@martin.sperl.org> References: <1450106426-2277-1-git-send-email-kernel@martin.sperl.org> Cc: Martin Sperl To: Mark Brown , Stephen Warren , Lee Jones , Eric Anholt , linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Return-path: In-Reply-To: <1450106426-2277-1-git-send-email-kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: From: Martin Sperl Remove all limitations in can_dma that inhibit the use of DMA To meet the limitiations of the HW we are now using the standardized version of spi_translate_message, that: * splits long transfers (> 60k) * aligns transfers (on 4 byte boundary) * merges transfers (for optimizations) Signed-off-by: Martin Sperl --- drivers/spi/spi-bcm2835.c | 58 +++++++++++++++------------------------------ 1 file changed, 19 insertions(+), 39 deletions(-) Changelog: V1 -> V3: move to use spi-core methods where possible diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index cf04960..75e4425 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -361,44 +361,8 @@ static bool bcm2835_spi_can_dma(struct spi_master *master, if (!gpio_is_valid(spi->cs_gpio)) return false; - /* we start DMA efforts only on bigger transfers */ - if (tfr->len < BCM2835_SPI_DMA_MIN_LENGTH) - return false; - - /* BCM2835_SPI_DLEN has defined a max transfer size as - * 16 bit, so max is 65535 - * we can revisit this by using an alternative transfer - * method - ideally this would get done without any more - * interaction... - */ - if (tfr->len > 65535) { - dev_warn_once(&spi->dev, - "transfer size of %d too big for dma-transfer\n", - tfr->len); - return false; - } - - /* if we run rx/tx_buf with word aligned addresses then we are OK */ - if ((((size_t)tfr->rx_buf & 3) == 0) && - (((size_t)tfr->tx_buf & 3) == 0)) - return true; - - /* otherwise we only allow transfers within the same page - * to avoid wasting time on dma_mapping when it is not practical - */ - if (((size_t)tfr->tx_buf & (PAGE_SIZE - 1)) + tfr->len > PAGE_SIZE) { - dev_warn_once(&spi->dev, - "Unaligned spi tx-transfer bridging page\n"); - return false; - } - if (((size_t)tfr->rx_buf & (PAGE_SIZE - 1)) + tfr->len > PAGE_SIZE) { - dev_warn_once(&spi->dev, - "Unaligned spi rx-transfer bridging page\n"); - return false; - } - - /* return OK */ - return true; + /* use the default implementation */ + return spi_can_dma_min_dma_len(master, spi, tfr); } static void bcm2835_dma_release(struct spi_master *master) @@ -461,7 +425,23 @@ static void bcm2835_dma_init(struct spi_master *master, struct device *dev) /* all went well, so set can_dma */ master->can_dma = bcm2835_spi_can_dma; - master->max_dma_len = 65535; /* limitation by BCM2835_SPI_DLEN */ + + /* set up transform message using the default implementation + * for size, alignment and merging transfers + */ + master->translate_message = spi_translate_message_size_align_merge; + + /* the minimum length when we run DMA */ + master->min_dma_len = BCM2835_SPI_DMA_MIN_LENGTH; + + /* the max_dma_len limited by BCM2835_SPI_DLEN is actually 65535, + * but for al practical purposes we use 15 pages (60k) + */ + master->max_dma_len = 15 * PAGE_SIZE; + + /* dma alignment is 4 bytes */ + master->dma_alignment = 4; + /* need to do TX AND RX DMA, so we need dummy buffers */ master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX; -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html