linux-kernel - [PATCH v2 4/4] spi: s3c64xx: Fix large transfers with DMA

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20220927112117.77599-5-vincent.whitchurch@axis.com>
Date:   Tue, 27 Sep 2022 13:21:17 +0200
From:   Vincent Whitchurch <vincent.whitchurch@...s.com>
To:     <broonie@...nel.org>, <krzysztof.kozlowski@...aro.org>,
        <andi@...zian.org>
CC:     <kernel@...s.com>,
        Vincent Whitchurch <vincent.whitchurch@...s.com>,
        <alim.akhtar@...sung.com>, <linux-spi@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-samsung-soc@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH v2 4/4] spi: s3c64xx: Fix large transfers with DMA

The COUNT_VALUE in the PACKET_CNT register is 16-bit so the maximum
value is 65535.  Asking the driver to transfer a larger size currently
leads to the DMA transfer timing out.  Implement ->max_transfer_size()
and have the core split the transfer as needed.

Fixes: 230d42d422e7 ("spi: Add s3c64xx SPI Controller driver")
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@...s.com>
---
 drivers/spi/spi-s3c64xx.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 651c35dd9124..71d324ec9a70 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -84,6 +84,7 @@
 #define S3C64XX_SPI_ST_TX_FIFORDY		(1<<0)
 
 #define S3C64XX_SPI_PACKET_CNT_EN		(1<<16)
+#define S3C64XX_SPI_PACKET_CNT_MASK		GENMASK(15, 0)
 
 #define S3C64XX_SPI_PND_TX_UNDERRUN_CLR		(1<<4)
 #define S3C64XX_SPI_PND_TX_OVERRUN_CLR		(1<<3)
@@ -711,6 +712,13 @@ static int s3c64xx_spi_prepare_message(struct spi_master *master,
 	return 0;
 }
 
+static size_t s3c64xx_spi_max_transfer_size(struct spi_device *spi)
+{
+	struct spi_controller *ctlr = spi->controller;
+
+	return ctlr->can_dma ? S3C64XX_SPI_PACKET_CNT_MASK : SIZE_MAX;
+}
+
 static int s3c64xx_spi_transfer_one(struct spi_master *master,
 				    struct spi_device *spi,
 				    struct spi_transfer *xfer)
@@ -1152,6 +1160,7 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
 	master->unprepare_transfer_hardware = s3c64xx_spi_unprepare_transfer;
 	master->prepare_message = s3c64xx_spi_prepare_message;
 	master->transfer_one = s3c64xx_spi_transfer_one;
+	master->max_transfer_size = s3c64xx_spi_max_transfer_size;
 	master->num_chipselect = sci->num_cs;
 	master->use_gpio_descriptors = true;
 	master->dma_alignment = 8;
-- 
2.34.1