From 08f15963bc751bc818294c0f75a9aaca299c4052 Mon Sep 17 00:00:00 2001 From: Abhishek Sahu Date: Mon, 12 Mar 2018 18:44:57 +0530 Subject: [PATCH 08/13] i2c: qup: use the complete transfer length to choose DMA mode Currently each message length in complete transfer is being checked for determining DMA mode and if any of the message length is less than FIFO length then non DMA mode is being used which will increase overhead. DMA can be used for any length and it should be determined with complete transfer length. Now, this patch selects DMA mode if the total length is greater than FIFO length. Signed-off-by: Abhishek Sahu Reviewed-by: Austin Christ Reviewed-by: Andy Gross Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-qup.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/drivers/i2c/busses/i2c-qup.c +++ b/drivers/i2c/busses/i2c-qup.c @@ -1300,7 +1300,8 @@ static int qup_i2c_xfer_v2(struct i2c_ad int num) { struct qup_i2c_dev *qup = i2c_get_adapdata(adap); - int ret, len, idx = 0; + int ret, idx = 0; + unsigned int total_len = 0; qup->bus_err = 0; qup->qup_err = 0; @@ -1326,14 +1327,14 @@ static int qup_i2c_xfer_v2(struct i2c_ad goto out; } - len = (msgs[idx].len > qup->out_fifo_sz) || - (msgs[idx].len > qup->in_fifo_sz); - - if (is_vmalloc_addr(msgs[idx].buf) || !len) + if (is_vmalloc_addr(msgs[idx].buf)) break; + + total_len += msgs[idx].len; } - if (idx == num) + if (idx == num && (total_len > qup->out_fifo_sz || + total_len > qup->in_fifo_sz)) qup->use_dma = true; }