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From: Dave Stevenson <dave.stevenson@raspberrypi.com>
To: Rob Herring <robh@kernel.org>,
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	Takashi Iwai <tiwai@suse.com>,
	Vladimir Murzin <vladimir.murzin@arm.com>,
	Phil Elwell <phil@raspberrypi.com>,
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	Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: devicetree@vger.kernel.org,
	linux-rpi-kernel@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
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	linux-spi@vger.kernel.org,
	iommu@lists.linux.dev,
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	Dave Stevenson <dave.stevenson@raspberrypi.com>
Subject: [PATCH 15/18] spi: bcm2835: Use phys addresses for slave DMA config
Date: Fri, 24 May 2024 19:26:59 +0100
Message-Id: <20240524182702.1317935-16-dave.stevenson@raspberrypi.com>
In-Reply-To: <20240524182702.1317935-1-dave.stevenson@raspberrypi.com>
References: <20240524182702.1317935-1-dave.stevenson@raspberrypi.com>
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From: Phil Elwell <phil@raspberrypi.com>

Contrary to what struct snd_dmaengine_dai_dma_data suggests, the
configuration of addresses of DMA slave interfaces should be done in
CPU physical addresses.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
---
 drivers/spi/spi-bcm2835.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index e1b9b1235787..e8242e0c4246 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -119,6 +119,7 @@ MODULE_PARM_DESC(polling_limit_us,
  */
 struct bcm2835_spi {
 	void __iomem *regs;
+	phys_addr_t phys_addr;
 	struct clk *clk;
 	struct gpio_desc *cs_gpio;
 	unsigned long clk_hz;
@@ -891,19 +892,8 @@ static int bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
 			    struct bcm2835_spi *bs)
 {
 	struct dma_slave_config slave_config;
-	const __be32 *addr;
-	dma_addr_t dma_reg_base;
 	int ret;
 
-	/* base address in dma-space */
-	addr = of_get_address(ctlr->dev.of_node, 0, NULL, NULL);
-	if (!addr) {
-		dev_err(dev, "could not get DMA-register address - not using dma mode\n");
-		/* Fall back to interrupt mode */
-		return 0;
-	}
-	dma_reg_base = be32_to_cpup(addr);
-
 	/* get tx/rx dma */
 	ctlr->dma_tx = dma_request_chan(dev, "tx");
 	if (IS_ERR(ctlr->dma_tx)) {
@@ -925,7 +915,7 @@ static int bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
 	 * or, in case of an RX-only transfer, cyclically copies from the zero
 	 * page to the FIFO using a preallocated, reusable descriptor.
 	 */
-	slave_config.dst_addr = (u32)(dma_reg_base + BCM2835_SPI_FIFO);
+	slave_config.dst_addr = bs->phys_addr + BCM2835_SPI_FIFO;
 	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 
 	ret = dmaengine_slave_config(ctlr->dma_tx, &slave_config);
@@ -964,9 +954,9 @@ static int bcm2835_dma_init(struct spi_controller *ctlr, struct device *dev,
 	 * RX FIFO or, in case of a TX-only transfer, cyclically writes a
 	 * precalculated value to the CS register to clear the RX FIFO.
 	 */
-	slave_config.src_addr = (u32)(dma_reg_base + BCM2835_SPI_FIFO);
+	slave_config.src_addr = bs->phys_addr + BCM2835_SPI_FIFO;
 	slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
-	slave_config.dst_addr = (u32)(dma_reg_base + BCM2835_SPI_CS);
+	slave_config.dst_addr = bs->phys_addr + BCM2835_SPI_CS;
 	slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
 
 	ret = dmaengine_slave_config(ctlr->dma_rx, &slave_config);
@@ -1336,6 +1326,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 {
 	struct spi_controller *ctlr;
 	struct bcm2835_spi *bs;
+	struct resource *iomem;
 	int err;
 
 	ctlr = devm_spi_alloc_host(&pdev->dev, sizeof(*bs));
@@ -1359,10 +1350,12 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
 	bs = spi_controller_get_devdata(ctlr);
 	bs->ctlr = ctlr;
 
-	bs->regs = devm_platform_ioremap_resource(pdev, 0);
+	bs->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &iomem);
 	if (IS_ERR(bs->regs))
 		return PTR_ERR(bs->regs);
 
+	bs->phys_addr = iomem->start;
+
 	bs->clk = devm_clk_get_enabled(&pdev->dev, NULL);
 	if (IS_ERR(bs->clk))
 		return dev_err_probe(&pdev->dev, PTR_ERR(bs->clk),
-- 
2.34.1