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i2c: ismt: 16-byte align the DMA buffer address
Use only a portion of the data buffer for DMA transfers, which is always 16-byte aligned. This makes the DMA buffer address 16-byte aligned and compensates for spurious hardware parity errors that may appear when the DMA buffer address is not 16-byte aligned. The data buffer is enlarged in order to accommodate any possible 16-byte alignment offset and changes the DMA code to only use a portion of the data buffer, which is 16-byte aligned. The symptom of the hardware issue is the same as the one addressed in v3.12-rc2-5-gbf41691 and manifests by transfers failing with EIO, with bit 9 being set in the ERRSTS register. Signed-off-by: Radu Rendec <radu.rendec@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
parent
38a99bd773
commit
5cd5f0bb0d
1 changed files with 19 additions and 18 deletions
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@ -172,7 +172,7 @@ struct ismt_priv {
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dma_addr_t io_rng_dma; /* descriptor HW base addr */
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u8 head; /* ring buffer head pointer */
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struct completion cmp; /* interrupt completion */
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u8 dma_buffer[I2C_SMBUS_BLOCK_MAX + 1]; /* temp R/W data buffer */
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u8 buffer[I2C_SMBUS_BLOCK_MAX + 16]; /* temp R/W data buffer */
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};
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/**
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@ -320,7 +320,7 @@ static int ismt_process_desc(const struct ismt_desc *desc,
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struct ismt_priv *priv, int size,
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char read_write)
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{
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u8 *dma_buffer = priv->dma_buffer;
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u8 *dma_buffer = PTR_ALIGN(&priv->buffer[0], 16);
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dev_dbg(&priv->pci_dev->dev, "Processing completed descriptor\n");
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__ismt_desc_dump(&priv->pci_dev->dev, desc);
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@ -395,11 +395,12 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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struct ismt_desc *desc;
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struct ismt_priv *priv = i2c_get_adapdata(adap);
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struct device *dev = &priv->pci_dev->dev;
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u8 *dma_buffer = PTR_ALIGN(&priv->buffer[0], 16);
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desc = &priv->hw[priv->head];
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/* Initialize the DMA buffer */
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memset(priv->dma_buffer, 0, sizeof(priv->dma_buffer));
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memset(priv->buffer, 0, sizeof(priv->buffer));
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/* Initialize the descriptor */
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memset(desc, 0, sizeof(struct ismt_desc));
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@ -448,8 +449,8 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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desc->wr_len_cmd = 2;
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dma_size = 2;
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dma_direction = DMA_TO_DEVICE;
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priv->dma_buffer[0] = command;
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priv->dma_buffer[1] = data->byte;
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dma_buffer[0] = command;
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dma_buffer[1] = data->byte;
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} else {
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/* Read Byte */
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dev_dbg(dev, "I2C_SMBUS_BYTE_DATA: READ\n");
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@ -468,9 +469,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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desc->wr_len_cmd = 3;
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dma_size = 3;
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dma_direction = DMA_TO_DEVICE;
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priv->dma_buffer[0] = command;
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priv->dma_buffer[1] = data->word & 0xff;
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priv->dma_buffer[2] = data->word >> 8;
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dma_buffer[0] = command;
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dma_buffer[1] = data->word & 0xff;
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dma_buffer[2] = data->word >> 8;
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} else {
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/* Read Word */
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dev_dbg(dev, "I2C_SMBUS_WORD_DATA: READ\n");
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@ -488,9 +489,9 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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desc->rd_len = 2;
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dma_size = 3;
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dma_direction = DMA_BIDIRECTIONAL;
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priv->dma_buffer[0] = command;
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priv->dma_buffer[1] = data->word & 0xff;
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priv->dma_buffer[2] = data->word >> 8;
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dma_buffer[0] = command;
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dma_buffer[1] = data->word & 0xff;
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dma_buffer[2] = data->word >> 8;
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break;
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case I2C_SMBUS_BLOCK_DATA:
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@ -501,8 +502,8 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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dma_direction = DMA_TO_DEVICE;
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desc->wr_len_cmd = dma_size;
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desc->control |= ISMT_DESC_BLK;
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priv->dma_buffer[0] = command;
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memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1);
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dma_buffer[0] = command;
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memcpy(&dma_buffer[1], &data->block[1], dma_size - 1);
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} else {
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/* Block Read */
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dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA: READ\n");
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@ -529,8 +530,8 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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dma_direction = DMA_TO_DEVICE;
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desc->wr_len_cmd = dma_size;
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desc->control |= ISMT_DESC_I2C;
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priv->dma_buffer[0] = command;
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memcpy(&priv->dma_buffer[1], &data->block[1], dma_size - 1);
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dma_buffer[0] = command;
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memcpy(&dma_buffer[1], &data->block[1], dma_size - 1);
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} else {
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/* i2c Block Read */
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dev_dbg(dev, "I2C_SMBUS_I2C_BLOCK_DATA: READ\n");
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@ -559,18 +560,18 @@ static int ismt_access(struct i2c_adapter *adap, u16 addr,
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if (dma_size != 0) {
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dev_dbg(dev, " dev=%p\n", dev);
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dev_dbg(dev, " data=%p\n", data);
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dev_dbg(dev, " dma_buffer=%p\n", priv->dma_buffer);
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dev_dbg(dev, " dma_buffer=%p\n", dma_buffer);
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dev_dbg(dev, " dma_size=%d\n", dma_size);
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dev_dbg(dev, " dma_direction=%d\n", dma_direction);
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dma_addr = dma_map_single(dev,
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priv->dma_buffer,
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dma_buffer,
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dma_size,
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dma_direction);
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if (dma_mapping_error(dev, dma_addr)) {
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dev_err(dev, "Error in mapping dma buffer %p\n",
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priv->dma_buffer);
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dma_buffer);
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return -EIO;
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}
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