From 7a72e3b94f97869377053a46eea1ee1d1e63c4d5 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Wed, 14 Feb 2024 15:59:39 +0100 Subject: [PATCH] i2c: i801: Fix block process call transactions [ Upstream commit c1c9d0f6f7f1dbf29db996bd8e166242843a5f21 ] According to the Intel datasheets, software must reset the block buffer index twice for block process call transactions: once before writing the outgoing data to the buffer, and once again before reading the incoming data from the buffer. The driver is currently missing the second reset, causing the wrong portion of the block buffer to be read. Signed-off-by: Jean Delvare Reported-by: Piotr Zakowski Closes: https://lore.kernel.org/linux-i2c/20240213120553.7b0ab120@endymion.delvare/ Fixes: 315cd67c9453 ("i2c: i801: Add Block Write-Block Read Process Call support") Reviewed-by: Alexander Sverdlin Signed-off-by: Andi Shyti Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-i801.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 15520d491..d6b945f5b 100755 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -543,11 +543,10 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, /* Set block buffer mode */ outb_p(inb_p(SMBAUXCTL(priv)) | SMBAUXCTL_E32B, SMBAUXCTL(priv)); - inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ - if (read_write == I2C_SMBUS_WRITE) { len = data->block[0]; outb_p(len, SMBHSTDAT0(priv)); + inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ for (i = 0; i < len; i++) outb_p(data->block[i+1], SMBBLKDAT(priv)); } @@ -563,6 +562,7 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, return -EPROTO; data->block[0] = len; + inb_p(SMBHSTCNT(priv)); /* reset the data buffer index */ for (i = 0; i < len; i++) data->block[i + 1] = inb_p(SMBBLKDAT(priv)); }