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[98.183.112.25]) by smtp.gmail.com with ESMTPSA id p26-20020a9d695a000000b006dc87c016e4sm426399oto.60.2024.01.26.14.00.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jan 2024 14:00:48 -0800 (PST) From: David Lechner To: Mark Brown , Florian Fainelli , Ray Jui , Scott Branden Cc: David Lechner , Broadcom internal kernel review list , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] spi: bcm2835: implement ctlr->max_transfer_size Date: Fri, 26 Jan 2024 16:00:23 -0600 Message-ID: <20240126220024.3926403-2-dlechner@baylibre.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240126_140150_214044_67E2A480 X-CRM114-Status: GOOD ( 17.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The core SPI code will handle splitting transfers if needed as long as ctlr->max_transfer_size is implemented. It does this in __spi_pump_transfer_message() immediately before calling ctlr->prepare_message. So effectively, this change does not alter the behavior of the driver. Also, several peripheral drivers make use of spi_max_transfer_size(), so this should improve compatibility with those drivers. Signed-off-by: David Lechner --- drivers/spi/spi-bcm2835.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index e709887eb2a9..e1b9b1235787 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -1117,19 +1117,6 @@ static int bcm2835_spi_prepare_message(struct spi_controller *ctlr, struct spi_device *spi = msg->spi; struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr); struct bcm2835_spidev *target = spi_get_ctldata(spi); - int ret; - - if (ctlr->can_dma) { - /* - * DMA transfers are limited to 16 bit (0 to 65535 bytes) by - * the SPI HW due to DLEN. Split up transfers (32-bit FIFO - * aligned) if the limit is exceeded. - */ - ret = spi_split_transfers_maxsize(ctlr, msg, 65532, - GFP_KERNEL | GFP_DMA); - if (ret) - return ret; - } /* * Set up clock polarity before spi_transfer_one_message() asserts @@ -1219,6 +1206,19 @@ static int bcm2835_spi_setup_dma(struct spi_controller *ctlr, return 0; } +static size_t bcm2835_spi_max_transfer_size(struct spi_device *spi) +{ + /* + * DMA transfers are limited to 16 bit (0 to 65535 bytes) by + * the SPI HW due to DLEN. Split up transfers (32-bit FIFO + * aligned) if the limit is exceeded. + */ + if (spi->controller->can_dma) + return 65532; + + return SIZE_MAX; +} + static int bcm2835_spi_setup(struct spi_device *spi) { struct spi_controller *ctlr = spi->controller; @@ -1348,6 +1348,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev) ctlr->mode_bits = BCM2835_SPI_MODE_BITS; ctlr->bits_per_word_mask = SPI_BPW_MASK(8); ctlr->num_chipselect = 3; + ctlr->max_transfer_size = bcm2835_spi_max_transfer_size; ctlr->setup = bcm2835_spi_setup; ctlr->cleanup = bcm2835_spi_cleanup; ctlr->transfer_one = bcm2835_spi_transfer_one;