From 5c135e151aee5f7e7f2ffb336cdb3e4e041caef4 Mon Sep 17 00:00:00 2001 From: Abhishek Sahu Date: Mon, 9 May 2016 18:14:31 +0530 Subject: [PATCH] i2c: qup: Fixed the DMA segments length 1. The current QCOM I2C driver code is failing for transfer length greater than 255. This is happening due to improper segments length as the I2C DMA segments can be maximum of 256 bytes. 2. The transfer length tlen was being initialized with 0 for 256 bytes, which is being passed for DMA mappings resulting in improper DMA mapping length. This patch fixes the above said problems by initializing the block count with the values calculated in qup_i2c_set_blk_data and calculating the remaining length for last DMA segment. Also, the block data length need to be decremented after each transfer. Additionally, this patch corrects the tlen assignment for DMA mapping. Signed-off-by: Abhishek Sahu Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-qup.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-qup.c b/drivers/i2c/busses/i2c-qup.c index 686f262e34f7..29139bbe8f85 100644 --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -659,23 +659,24 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, u8 *tags; while (idx < num) { - blocks = (msg->len + limit) / limit; - rem = msg->len % limit; tx_len = 0, len = 0, i = 0; qup->is_last = (idx == (num - 1)); qup_i2c_set_blk_data(qup, msg); + blocks = qup->blk.count; + rem = msg->len - (blocks - 1) * limit; + if (msg->flags & I2C_M_RD) { rx_nents += (blocks * 2) + 1; tx_nents += 1; while (qup->blk.pos < blocks) { - /* length set to '0' implies 256 bytes */ - tlen = (i == (blocks - 1)) ? rem : 0; + tlen = (i == (blocks - 1)) ? rem : limit; tags = &qup->start_tag.start[off + len]; len += qup_i2c_set_tags(tags, qup, msg, 1); + qup->blk.data_len -= tlen; /* scratch buf to read the start and len tags */ ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++], @@ -712,9 +713,10 @@ static int qup_i2c_bam_do_xfer(struct qup_i2c_dev *qup, struct i2c_msg *msg, tx_nents += (blocks * 2); while (qup->blk.pos < blocks) { - tlen = (i == (blocks - 1)) ? rem : 0; + tlen = (i == (blocks - 1)) ? rem : limit; tags = &qup->start_tag.start[off + tx_len]; len = qup_i2c_set_tags(tags, qup, msg, 1); + qup->blk.data_len -= tlen; ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++], tags, len, -- 2.39.5