ipq40xx: backport I2C QUP driver changes from 4.17

Backport below changes for I2C QUP driver from v4.17:

  0668bc44a426 i2c: qup: fix copyrights and update to SPDX identifier
  7239872fb340 i2c: qup: fixed releasing dma without flush operation completion
  eb422b539c1f i2c: qup: minor code reorganization for use_dma
  6d5f37f166bb i2c: qup: remove redundant variables for BAM SG count
  c5adc0fa63a9 i2c: qup: schedule EOT and FLUSH tags at the end of transfer
  7e6c35fe602d i2c: qup: fix the transfer length for BAM RX EOT FLUSH tags
  3f450d3eea14 i2c: qup: proper error handling for i2c error in BAM mode
  08f15963bc75 i2c: qup: use the complete transfer length to choose DMA mode
  ecb6e1e5f435 i2c: qup: change completion timeout according to transfer length
  6f2f0f6465ac i2c: qup: fix buffer overflow for multiple msg of maximum xfer len
  f7714b4e451b i2c: qup: send NACK for last read sub transfers
  fbfab1ab0658 i2c: qup: reorganization of driver code to remove polling for qup v1
  7545c7dba169 i2c: qup: reorganization of driver code to remove polling for qup v2

This fixes various I2C issues observed on AP120C-AC board equipped with
Atmel/Microchip AT97SC3205T TPM module.

Tested-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Piotr Dymacz <pepe2k@gmail.com>

1 files changed, 174 insertions, 0 deletions

diff --git a/target/linux/ipq40xx/patches-4.14/088-0004-i2c-qup-remove-redundant-variables-for-BAM-SG-count.patch b/target/linux/ipq40xx/patches-4.14/088-0004-i2c-qup-remove-redundant-variables-for-BAM-SG-count.patch
new file mode 100644
index 0000000000..e18af41789
--- /dev/null
+++ b/target/linux/ipq40xx/patches-4.14/088-0004-i2c-qup-remove-redundant-variables-for-BAM-SG-count.patch
@@ -0,0 +1,174 @@
+From 6d5f37f166bb07b04b4d42e9d1f5427b7931cd3c Mon Sep 17 00:00:00 2001
+From: Abhishek Sahu <absahu@codeaurora.org>
+Date: Mon, 12 Mar 2018 18:44:53 +0530
+Subject: [PATCH 04/13] i2c: qup: remove redundant variables for BAM SG count
+
+The rx_nents and tx_nents are redundant. rx_buf and tx_buf can
+be used for total number of SG entries. Since rx_buf and tx_buf
+give the impression that it is buffer instead of count so rename
+it to tx_cnt and rx_cnt for giving it more meaningful variable
+name.
+
+Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
+Reviewed-by: Austin Christ <austinwc@codeaurora.org>
+Reviewed-by: Andy Gross <andy.gross@linaro.org>
+Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
+---
+ drivers/i2c/busses/i2c-qup.c | 42 ++++++++++++++++--------------------
+ 1 file changed, 18 insertions(+), 24 deletions(-)
+
+--- a/drivers/i2c/busses/i2c-qup.c
++++ b/drivers/i2c/busses/i2c-qup.c
+@@ -683,8 +683,8 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 	struct dma_async_tx_descriptor *txd, *rxd = NULL;
+ 	int ret = 0, idx = 0, limit = QUP_READ_LIMIT;
+ 	dma_cookie_t cookie_rx, cookie_tx;
+-	u32 rx_nents = 0, tx_nents = 0, len, blocks, rem;
+-	u32 i, tlen, tx_len, tx_buf = 0, rx_buf = 0, off = 0;
++	u32 len, blocks, rem;
++	u32 i, tlen, tx_len, tx_cnt = 0, rx_cnt = 0, off = 0;
+ 	u8 *tags;
+ 
+ 	while (idx < num) {
+@@ -698,9 +698,6 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 		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) {
+ 				tlen = (i == (blocks - 1)) ? rem : limit;
+ 				tags = &qup->start_tag.start[off + len];
+@@ -708,14 +705,14 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 				qup->blk.data_len -= tlen;
+ 
+ 				/* scratch buf to read the start and len tags */
+-				ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
++				ret = qup_sg_set_buf(&qup->brx.sg[rx_cnt++],
+ 						     &qup->brx.tag.start[0],
+ 						     2, qup, DMA_FROM_DEVICE);
+ 
+ 				if (ret)
+ 					return ret;
+ 
+-				ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
++				ret = qup_sg_set_buf(&qup->brx.sg[rx_cnt++],
+ 						     &msg->buf[limit * i],
+ 						     tlen, qup,
+ 						     DMA_FROM_DEVICE);
+@@ -725,7 +722,7 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 				i++;
+ 				qup->blk.pos = i;
+ 			}
+-			ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
++			ret = qup_sg_set_buf(&qup->btx.sg[tx_cnt++],
+ 					     &qup->start_tag.start[off],
+ 					     len, qup, DMA_TO_DEVICE);
+ 			if (ret)
+@@ -733,28 +730,26 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 
+ 			off += len;
+ 			/* scratch buf to read the BAM EOT and FLUSH tags */
+-			ret = qup_sg_set_buf(&qup->brx.sg[rx_buf++],
++			ret = qup_sg_set_buf(&qup->brx.sg[rx_cnt++],
+ 					     &qup->brx.tag.start[0],
+ 					     2, qup, DMA_FROM_DEVICE);
+ 			if (ret)
+ 				return ret;
+ 		} else {
+-			tx_nents += (blocks * 2);
+-
+ 			while (qup->blk.pos < blocks) {
+ 				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++],
++				ret = qup_sg_set_buf(&qup->btx.sg[tx_cnt++],
+ 						     tags, len,
+ 						     qup, DMA_TO_DEVICE);
+ 				if (ret)
+ 					return ret;
+ 
+ 				tx_len += len;
+-				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
++				ret = qup_sg_set_buf(&qup->btx.sg[tx_cnt++],
+ 						     &msg->buf[limit * i],
+ 						     tlen, qup, DMA_TO_DEVICE);
+ 				if (ret)
+@@ -766,26 +761,25 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 
+ 			if (idx == (num - 1)) {
+ 				len = 1;
+-				if (rx_nents) {
++				if (rx_cnt) {
+ 					qup->btx.tag.start[0] =
+ 							QUP_BAM_INPUT_EOT;
+ 					len++;
+ 				}
+ 				qup->btx.tag.start[len - 1] =
+ 							QUP_BAM_FLUSH_STOP;
+-				ret = qup_sg_set_buf(&qup->btx.sg[tx_buf++],
++				ret = qup_sg_set_buf(&qup->btx.sg[tx_cnt++],
+ 						     &qup->btx.tag.start[0],
+ 						     len, qup, DMA_TO_DEVICE);
+ 				if (ret)
+ 					return ret;
+-				tx_nents += 1;
+ 			}
+ 		}
+ 		idx++;
+ 		msg++;
+ 	}
+ 
+-	txd = dmaengine_prep_slave_sg(qup->btx.dma, qup->btx.sg, tx_nents,
++	txd = dmaengine_prep_slave_sg(qup->btx.dma, qup->btx.sg, tx_cnt,
+ 				      DMA_MEM_TO_DEV,
+ 				      DMA_PREP_INTERRUPT | DMA_PREP_FENCE);
+ 	if (!txd) {
+@@ -794,7 +788,7 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 		goto desc_err;
+ 	}
+ 
+-	if (!rx_nents) {
++	if (!rx_cnt) {
+ 		txd->callback = qup_i2c_bam_cb;
+ 		txd->callback_param = qup;
+ 	}
+@@ -807,9 +801,9 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 
+ 	dma_async_issue_pending(qup->btx.dma);
+ 
+-	if (rx_nents) {
++	if (rx_cnt) {
+ 		rxd = dmaengine_prep_slave_sg(qup->brx.dma, qup->brx.sg,
+-					      rx_nents, DMA_DEV_TO_MEM,
++					      rx_cnt, DMA_DEV_TO_MEM,
+ 					      DMA_PREP_INTERRUPT);
+ 		if (!rxd) {
+ 			dev_err(qup->dev, "failed to get rx desc\n");
+@@ -844,7 +838,7 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 			goto desc_err;
+ 		}
+ 
+-		if (rx_nents)
++		if (rx_cnt)
+ 			writel(QUP_BAM_INPUT_EOT,
+ 			       qup->base + QUP_OUT_FIFO_BASE);
+ 
+@@ -862,10 +856,10 @@ static int qup_i2c_bam_do_xfer(struct qu
+ 	}
+ 
+ desc_err:
+-	dma_unmap_sg(qup->dev, qup->btx.sg, tx_nents, DMA_TO_DEVICE);
++	dma_unmap_sg(qup->dev, qup->btx.sg, tx_cnt, DMA_TO_DEVICE);
+ 
+-	if (rx_nents)
+-		dma_unmap_sg(qup->dev, qup->brx.sg, rx_nents,
++	if (rx_cnt)
++		dma_unmap_sg(qup->dev, qup->brx.sg, rx_cnt,
+ 			     DMA_FROM_DEVICE);
+ 
+ 	return ret;