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Message-Id: <20190116161713.12748-1-laurentiu.tudor@nxp.com>
Date: Wed, 16 Jan 2019 18:17:13 +0200
From: Laurentiu Tudor <laurentiu.tudor@....com>
To: linux-i2c@...r.kernel.org, linux-imx@....com,
iommu@...ts.linux-foundation.org, kernel@...gutronix.de,
wsa@...-dreams.de
Cc: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
robin.murphy@....com, Laurentiu Tudor <laurentiu.tudor@....com>
Subject: [RFC PATCH] i2c: imx: dma map the i2c data i/o register
This is an attempt to fix an iommu exception when doing dma to the
i2c controller with EDMA. Without these mappings the smmu raises a
context fault [1] exactly with the address of the i2c data i/o reg.
This was seen on an NXP LS1043A chip while working on enabling SMMU.
[1] arm-smmu 9000000.iommu: Unhandled context fault: fsr=0x402,
iova=0x02180004, fsynr=0x150021, cb=7
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@....com>
---
drivers/i2c/busses/i2c-imx.c | 57 +++++++++++++++++++++++++++++-------
1 file changed, 47 insertions(+), 10 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 4e34b1572756..07cc8f4b45b9 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -202,6 +202,9 @@ struct imx_i2c_struct {
struct pinctrl_state *pinctrl_pins_gpio;
struct imx_i2c_dma *dma;
+
+ dma_addr_t dma_tx_addr;
+ dma_addr_t dma_rx_addr;
};
static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
@@ -274,17 +277,20 @@ static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx,
/* Functions for DMA support */
static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
- dma_addr_t phy_addr)
+ phys_addr_t phy_addr)
{
struct imx_i2c_dma *dma;
struct dma_slave_config dma_sconfig;
struct device *dev = &i2c_imx->adapter.dev;
int ret;
+ phys_addr_t i2dr_pa;
dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL);
if (!dma)
return -ENOMEM;
+ i2dr_pa = phy_addr + (IMX_I2C_I2DR << i2c_imx->hwdata->regshift);
+
dma->chan_tx = dma_request_chan(dev, "tx");
if (IS_ERR(dma->chan_tx)) {
ret = PTR_ERR(dma->chan_tx);
@@ -293,15 +299,25 @@ static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
goto fail_al;
}
- dma_sconfig.dst_addr = phy_addr +
- (IMX_I2C_I2DR << i2c_imx->hwdata->regshift);
+ i2c_imx->dma_tx_addr = dma_map_resource(dma->chan_tx->device->dev,
+ i2dr_pa,
+ DMA_SLAVE_BUSWIDTH_1_BYTE,
+ DMA_MEM_TO_DEV, 0);
+ ret = dma_mapping_error(dma->chan_tx->device->dev,
+ i2c_imx->dma_tx_addr);
+ if (ret) {
+ dev_err(dev, "can't dma map tx destination (%d)\n", ret);
+ goto fail_tx;
+ }
+
+ dma_sconfig.dst_addr = i2c_imx->dma_tx_addr;
dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_sconfig.dst_maxburst = 1;
dma_sconfig.direction = DMA_MEM_TO_DEV;
ret = dmaengine_slave_config(dma->chan_tx, &dma_sconfig);
if (ret < 0) {
dev_err(dev, "can't configure tx channel (%d)\n", ret);
- goto fail_tx;
+ goto fail_tx_dma;
}
dma->chan_rx = dma_request_chan(dev, "rx");
@@ -309,18 +325,28 @@ static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
ret = PTR_ERR(dma->chan_rx);
if (ret != -ENODEV && ret != -EPROBE_DEFER)
dev_err(dev, "can't request DMA rx channel (%d)\n", ret);
- goto fail_tx;
+ goto fail_tx_dma;
}
- dma_sconfig.src_addr = phy_addr +
- (IMX_I2C_I2DR << i2c_imx->hwdata->regshift);
+ i2c_imx->dma_rx_addr = dma_map_resource(dma->chan_rx->device->dev,
+ i2dr_pa,
+ DMA_SLAVE_BUSWIDTH_1_BYTE,
+ DMA_DEV_TO_MEM, 0);
+ ret = dma_mapping_error(dma->chan_rx->device->dev,
+ i2c_imx->dma_rx_addr);
+ if (ret) {
+ dev_err(dev, "can't dma map rx source (%d)\n", ret);
+ goto fail_rx;
+ }
+
+ dma_sconfig.src_addr = i2c_imx->dma_rx_addr;
dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_sconfig.src_maxburst = 1;
dma_sconfig.direction = DMA_DEV_TO_MEM;
ret = dmaengine_slave_config(dma->chan_rx, &dma_sconfig);
if (ret < 0) {
dev_err(dev, "can't configure rx channel (%d)\n", ret);
- goto fail_rx;
+ goto fail_rx_dma;
}
i2c_imx->dma = dma;
@@ -330,8 +356,14 @@ static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
return 0;
+fail_rx_dma:
+ dma_unmap_resource(dma->chan_rx->device->dev, i2c_imx->dma_rx_addr,
+ DMA_SLAVE_BUSWIDTH_1_BYTE, DMA_DEV_TO_MEM, 0);
fail_rx:
dma_release_channel(dma->chan_rx);
+fail_tx_dma:
+ dma_unmap_resource(dma->chan_tx->device->dev, i2c_imx->dma_tx_addr,
+ DMA_SLAVE_BUSWIDTH_1_BYTE, DMA_MEM_TO_DEV, 0);
fail_tx:
dma_release_channel(dma->chan_tx);
fail_al:
@@ -1057,7 +1089,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
void __iomem *base;
int irq, ret;
- dma_addr_t phy_addr;
+ phys_addr_t phy_addr;
dev_dbg(&pdev->dev, "<%s>\n", __func__);
@@ -1072,7 +1104,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
if (IS_ERR(base))
return PTR_ERR(base);
- phy_addr = (dma_addr_t)res->start;
+ phy_addr = res->start;
i2c_imx = devm_kzalloc(&pdev->dev, sizeof(*i2c_imx), GFP_KERNEL);
if (!i2c_imx)
return -ENOMEM;
@@ -1220,6 +1252,11 @@ static int i2c_imx_remove(struct platform_device *pdev)
pm_runtime_put_noidle(&pdev->dev);
pm_runtime_disable(&pdev->dev);
+ dma_unmap_resource(&pdev->dev, i2c_imx->dma_tx_addr,
+ DMA_SLAVE_BUSWIDTH_1_BYTE, DMA_MEM_TO_DEV, 0);
+ dma_unmap_resource(&pdev->dev, i2c_imx->dma_rx_addr,
+ DMA_SLAVE_BUSWIDTH_1_BYTE, DMA_DEV_TO_MEM, 0);
+
return 0;
}
--
2.17.1
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