On Mon, 4 Feb 2013 10:47:44 +0100, Jean Delvare wrote:
> I have backported your code to kernel 3.0 and I'll get back to you when
> I finally get a chance to test it.

OK, I am done with the backport and testing. The test system I have
access to appears to have a single slave on the second iSMT channel, at
address 0x54. I have no idea what this device is so my testing is
fairly limited, in particular I can't test writes. But at least I could
test the quick command and read byte transactions. I believe the
following fix is needed on top of your patch to make non-quick,
non-block transactions right:

---
 i2c-ismt.c |   35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

--- i2c-ismt.orig/i2c-ismt.c
+++ i2c-ismt/i2c-ismt.c
@@ -329,10 +329,23 @@ static int ismt_process_desc(const struc
        __ismt_desc_dump(&priv->pci_dev->dev, desc);
 
        if (desc->status & ISMT_DESC_SCS) {
-               if ((size != I2C_SMBUS_QUICK) &&
-                   (read_write == I2C_SMBUS_READ)) {
+               if (read_write == I2C_SMBUS_WRITE &&
+                   size != I2C_SMBUS_PROC_CALL)
+                       return 0;
+
+               switch (size) {
+               case I2C_SMBUS_BYTE:
+               case I2C_SMBUS_BYTE_DATA:
+                       data->byte = dma_buffer[0];
+                       break;
+               case I2C_SMBUS_WORD_DATA:
+               case I2C_SMBUS_PROC_CALL:
+                       data->word = dma_buffer[0] | (dma_buffer[1] << 8);
+                       break;
+               case I2C_SMBUS_BLOCK_DATA:
                        memcpy(&data->block[1], dma_buffer, desc->rxbytes);
                        data->block[0] = desc->rxbytes;
+                       break;
                }
                return 0;
        }
@@ -426,6 +439,8 @@ static int ismt_access(struct i2c_adapte
                        desc->wr_len_cmd = 2;
                        dma_size = 2;
                        dma_direction = DMA_TO_DEVICE;
+                       priv->dma_buffer[0] = command;
+                       priv->dma_buffer[1] = data->byte;
                } else {
                        /* Read Byte */
                        dev_dbg(dev, "I2C_SMBUS_BYTE_DATA:  READ\n");
@@ -444,6 +459,9 @@ static int ismt_access(struct i2c_adapte
                        desc->wr_len_cmd = 3;
                        dma_size = 3;
                        dma_direction = DMA_TO_DEVICE;
+                       priv->dma_buffer[0] = command;
+                       priv->dma_buffer[1] = data->word & 0xff;
+                       priv->dma_buffer[2] = data->word >> 8;
                } else {
                        /* Read Word */
                        dev_dbg(dev, "I2C_SMBUS_WORD_DATA:  READ\n");
@@ -461,6 +479,9 @@ static int ismt_access(struct i2c_adapte
                desc->rd_len = 2;
                dma_size = 3;
                dma_direction = DMA_BIDIRECTIONAL;
+               priv->dma_buffer[0] = command;
+               priv->dma_buffer[1] = data->word & 0xff;
+               priv->dma_buffer[2] = data->word >> 8;
                break;
 
        case I2C_SMBUS_BLOCK_DATA:
@@ -471,6 +492,8 @@ static int ismt_access(struct i2c_adapte
                        dma_direction = DMA_TO_DEVICE;
                        desc->wr_len_cmd = dma_size;
                        desc->control |= ISMT_DESC_BLK;
+                       priv->dma_buffer[0] = command;
+                       memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
                } else {
                        /* Block Read */
                        dev_dbg(dev, "I2C_SMBUS_BLOCK_DATA:  READ\n");
@@ -488,14 +511,6 @@ static int ismt_access(struct i2c_adapte
                return -EOPNOTSUPP;
        }
 
-       /* Create a temporary buffer for the DMA transaction */
-       /* and insert the command at the beginning of the buffer */
-       if ((read_write == I2C_SMBUS_WRITE) &&
-           (size > I2C_SMBUS_BYTE)) {
-               memcpy(&priv->dma_buffer[1], &data->block[1], dma_size);
-               priv->dma_buffer[0] = command;
-       }
-
        /* map the data buffer */
        if (dma_size != 0) {
                dev_dbg(dev, " dev=%p\n", dev);

Maybe that's what Seth was missing. Seth, can you please try this patch
of mine and let us know if it helps? Warning: I was only able to test
the quick, receive byte and read byte transactions.

-- 
Jean Delvare
--
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