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Date: Wed, 20 Nov 2019 10:44:06 +0900
From: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@...hiba.co.jp>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: linux-kernel@...r.kernel.org, stable@...r.kernel.org,
Jun Gao <jun.gao@...iatek.com>,
Wolfram Sang <wsa@...-dreams.de>,
Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 4.19 127/422] i2c: mediatek: Use DMA safe buffers for i2c
transactions
Hi,
On Tue, Nov 19, 2019 at 06:15:24AM +0100, Greg Kroah-Hartman wrote:
> From: Jun Gao <jun.gao@...iatek.com>
>
> [ Upstream commit fc66b39fe36acfd06f716e338de7cd8f9550fad2 ]
>
> DMA mode will always be used in i2c transactions, try to allocate
> a DMA safe buffer if the buf of struct i2c_msg used is not DMA safe.
>
> Signed-off-by: Jun Gao <jun.gao@...iatek.com>
> Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
> Signed-off-by: Sasha Levin <sashal@...nel.org>
This patch requires the following additional commit:
commit bc1a7f75c85e226e82f183d30d75c357f92b6029
Author: Hsin-Yi Wang <hsinyi@...omium.org>
Date: Fri Feb 15 17:02:02 2019 +0800
i2c: mediatek: modify threshold passed to i2c_get_dma_safe_msg_buf()
DMA with zero-length transfers doesn't make sense and this HW doesn't
support them at all, so increase the threshold.
Fixes: fc66b39fe36a ("i2c: mediatek: Use DMA safe buffers for i2c transactions")
Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
[wsa: reworded commit message]
Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
Please apply this commit.
Best regards,
Nobuhiro
> ---
> drivers/i2c/busses/i2c-mt65xx.c | 62 +++++++++++++++++++++++++++++----
> 1 file changed, 55 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index 1e57f58fcb001..a74ef76705e0c 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -441,6 +441,8 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> u16 control_reg;
> u16 restart_flag = 0;
> u32 reg_4g_mode;
> + u8 *dma_rd_buf = NULL;
> + u8 *dma_wr_buf = NULL;
> dma_addr_t rpaddr = 0;
> dma_addr_t wpaddr = 0;
> int ret;
> @@ -500,10 +502,18 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> if (i2c->op == I2C_MASTER_RD) {
> writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
> writel(I2C_DMA_CON_RX, i2c->pdmabase + OFFSET_CON);
> - rpaddr = dma_map_single(i2c->dev, msgs->buf,
> +
> + dma_rd_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
> + if (!dma_rd_buf)
> + return -ENOMEM;
> +
> + rpaddr = dma_map_single(i2c->dev, dma_rd_buf,
> msgs->len, DMA_FROM_DEVICE);
> - if (dma_mapping_error(i2c->dev, rpaddr))
> + if (dma_mapping_error(i2c->dev, rpaddr)) {
> + i2c_put_dma_safe_msg_buf(dma_rd_buf, msgs, false);
> +
> return -ENOMEM;
> + }
>
> if (i2c->dev_comp->support_33bits) {
> reg_4g_mode = mtk_i2c_set_4g_mode(rpaddr);
> @@ -515,10 +525,18 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> } else if (i2c->op == I2C_MASTER_WR) {
> writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
> writel(I2C_DMA_CON_TX, i2c->pdmabase + OFFSET_CON);
> - wpaddr = dma_map_single(i2c->dev, msgs->buf,
> +
> + dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
> + if (!dma_wr_buf)
> + return -ENOMEM;
> +
> + wpaddr = dma_map_single(i2c->dev, dma_wr_buf,
> msgs->len, DMA_TO_DEVICE);
> - if (dma_mapping_error(i2c->dev, wpaddr))
> + if (dma_mapping_error(i2c->dev, wpaddr)) {
> + i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
> +
> return -ENOMEM;
> + }
>
> if (i2c->dev_comp->support_33bits) {
> reg_4g_mode = mtk_i2c_set_4g_mode(wpaddr);
> @@ -530,16 +548,39 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> } else {
> writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_INT_FLAG);
> writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_CON);
> - wpaddr = dma_map_single(i2c->dev, msgs->buf,
> +
> + dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
> + if (!dma_wr_buf)
> + return -ENOMEM;
> +
> + wpaddr = dma_map_single(i2c->dev, dma_wr_buf,
> msgs->len, DMA_TO_DEVICE);
> - if (dma_mapping_error(i2c->dev, wpaddr))
> + if (dma_mapping_error(i2c->dev, wpaddr)) {
> + i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
> +
> return -ENOMEM;
> - rpaddr = dma_map_single(i2c->dev, (msgs + 1)->buf,
> + }
> +
> + dma_rd_buf = i2c_get_dma_safe_msg_buf((msgs + 1), 0);
> + if (!dma_rd_buf) {
> + dma_unmap_single(i2c->dev, wpaddr,
> + msgs->len, DMA_TO_DEVICE);
> +
> + i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
> +
> + return -ENOMEM;
> + }
> +
> + rpaddr = dma_map_single(i2c->dev, dma_rd_buf,
> (msgs + 1)->len,
> DMA_FROM_DEVICE);
> if (dma_mapping_error(i2c->dev, rpaddr)) {
> dma_unmap_single(i2c->dev, wpaddr,
> msgs->len, DMA_TO_DEVICE);
> +
> + i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
> + i2c_put_dma_safe_msg_buf(dma_rd_buf, (msgs + 1), false);
> +
> return -ENOMEM;
> }
>
> @@ -578,14 +619,21 @@ static int mtk_i2c_do_transfer(struct mtk_i2c *i2c, struct i2c_msg *msgs,
> if (i2c->op == I2C_MASTER_WR) {
> dma_unmap_single(i2c->dev, wpaddr,
> msgs->len, DMA_TO_DEVICE);
> +
> + i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, true);
> } else if (i2c->op == I2C_MASTER_RD) {
> dma_unmap_single(i2c->dev, rpaddr,
> msgs->len, DMA_FROM_DEVICE);
> +
> + i2c_put_dma_safe_msg_buf(dma_rd_buf, msgs, true);
> } else {
> dma_unmap_single(i2c->dev, wpaddr, msgs->len,
> DMA_TO_DEVICE);
> dma_unmap_single(i2c->dev, rpaddr, (msgs + 1)->len,
> DMA_FROM_DEVICE);
> +
> + i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, true);
> + i2c_put_dma_safe_msg_buf(dma_rd_buf, (msgs + 1), true);
> }
>
> if (ret == 0) {
> --
> 2.20.1
>
>
>
>
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