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Message-ID: <049c28e9-1211-377f-941d-ba169645dd24@codeaurora.org>
Date: Wed, 9 Dec 2020 18:29:10 +0530
From: Akash Asthana <akashast@...eaurora.org>
To: Roja Rani Yarubandi <rojay@...eaurora.org>, wsa@...nel.org
Cc: swboyd@...omium.org, dianders@...omium.org,
saiprakash.ranjan@...eaurora.org, gregkh@...uxfoundation.org,
mka@...omium.org, msavaliy@....qualcomm.com, skakit@...eaurora.org,
vkaur@...eaurora.org, pyarlaga@...eaurora.org,
rnayak@...eaurora.org, agross@...nel.org,
bjorn.andersson@...aro.org, linux-arm-msm@...r.kernel.org,
linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
sumit.semwal@...aro.org, linux-media@...r.kernel.org
Subject: Re: [RESEND PATCH V6 1/2] i2c: i2c-qcom-geni: Store DMA mapping data
in geni_i2c_dev struct
Hi Roja,
On 12/3/2020 4:01 PM, Roja Rani Yarubandi wrote:
> Store DMA mapping data in geni_i2c_dev struct to enhance DMA mapping
> data scope. For example during shutdown callback to unmap DMA mapping,
> this stored DMA mapping data can be used to call geni_se_tx_dma_unprep
> and geni_se_rx_dma_unprep functions.
>
> Add two helper functions geni_i2c_rx_msg_cleanup and
> geni_i2c_tx_msg_cleanup to unwrap the things after rx/tx FIFO/DMA
> transfers, so that the same can be used in geni_i2c_stop_xfer()
> function during shutdown callback.
>
> Signed-off-by: Roja Rani Yarubandi <rojay@...eaurora.org>
> ---
> Changes in V5:
> - As per Stephen's comments separated this patch from shutdown
> callback patch, gi2c->cur = NULL is not removed from
> geni_i2c_abort_xfer(), and made a copy of gi2c->cur and passed
> to cleanup functions.
>
> Changes in V6:
> - Added spin_lock/unlock in geni_i2c_rx_msg_cleanup() and
> geni_i2c_tx_msg_cleanup() functions.
>
> drivers/i2c/busses/i2c-qcom-geni.c | 69 +++++++++++++++++++++++-------
> 1 file changed, 53 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> index dce75b85253c..bfbc80f65006 100644
> --- a/drivers/i2c/busses/i2c-qcom-geni.c
> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> @@ -86,6 +86,9 @@ struct geni_i2c_dev {
> u32 clk_freq_out;
> const struct geni_i2c_clk_fld *clk_fld;
> int suspended;
> + void *dma_buf;
> + size_t xfer_len;
> + dma_addr_t dma_addr;
> };
>
> struct geni_i2c_err_log {
> @@ -348,14 +351,49 @@ static void geni_i2c_tx_fsm_rst(struct geni_i2c_dev *gi2c)
> dev_err(gi2c->se.dev, "Timeout resetting TX_FSM\n");
> }
>
> +static void geni_i2c_rx_msg_cleanup(struct geni_i2c_dev *gi2c,
> + struct i2c_msg *cur)
> +{
> + struct geni_se *se = &gi2c->se;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&gi2c->lock, flags);
> + gi2c->cur_rd = 0;
> + if (gi2c->dma_buf) {
> + if (gi2c->err)
> + geni_i2c_rx_fsm_rst(gi2c);
Which race we are trying to avoid here by holding spinlock?
We cannot call any sleeping API by holding spinlock, geni_i2c_rx_fsm_rst
calls *wait-for-completion*, which is a sleeping call.
> + geni_se_rx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);
> + i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);
> + }
> + spin_unlock_irqrestore(&gi2c->lock, flags);
> +}
> +
> +static void geni_i2c_tx_msg_cleanup(struct geni_i2c_dev *gi2c,
> + struct i2c_msg *cur)
> +{
> + struct geni_se *se = &gi2c->se;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&gi2c->lock, flags);
> + gi2c->cur_wr = 0;
> + if (gi2c->dma_buf) {
> + if (gi2c->err)
> + geni_i2c_tx_fsm_rst(gi2c);
Same here
Regards,
Akash
> + geni_se_tx_dma_unprep(se, gi2c->dma_addr, gi2c->xfer_len);
> + i2c_put_dma_safe_msg_buf(gi2c->dma_buf, cur, !gi2c->err);
> + }
> + spin_unlock_irqrestore(&gi2c->lock, flags);
> +}
> +
> static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> u32 m_param)
> {
> - dma_addr_t rx_dma;
> + dma_addr_t rx_dma = 0;
> unsigned long time_left;
> void *dma_buf = NULL;
> struct geni_se *se = &gi2c->se;
> size_t len = msg->len;
> + struct i2c_msg *cur;
>
> if (!of_machine_is_compatible("lenovo,yoga-c630"))
> dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
> @@ -372,19 +410,18 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> geni_se_select_mode(se, GENI_SE_FIFO);
> i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
> dma_buf = NULL;
> + } else {
> + gi2c->xfer_len = len;
> + gi2c->dma_addr = rx_dma;
> + gi2c->dma_buf = dma_buf;
> }
>
> + cur = gi2c->cur;
> time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
> if (!time_left)
> geni_i2c_abort_xfer(gi2c);
>
> - gi2c->cur_rd = 0;
> - if (dma_buf) {
> - if (gi2c->err)
> - geni_i2c_rx_fsm_rst(gi2c);
> - geni_se_rx_dma_unprep(se, rx_dma, len);
> - i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
> - }
> + geni_i2c_rx_msg_cleanup(gi2c, cur);
>
> return gi2c->err;
> }
> @@ -392,11 +429,12 @@ static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> u32 m_param)
> {
> - dma_addr_t tx_dma;
> + dma_addr_t tx_dma = 0;
> unsigned long time_left;
> void *dma_buf = NULL;
> struct geni_se *se = &gi2c->se;
> size_t len = msg->len;
> + struct i2c_msg *cur;
>
> if (!of_machine_is_compatible("lenovo,yoga-c630"))
> dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
> @@ -413,22 +451,21 @@ static int geni_i2c_tx_one_msg(struct geni_i2c_dev *gi2c, struct i2c_msg *msg,
> geni_se_select_mode(se, GENI_SE_FIFO);
> i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
> dma_buf = NULL;
> + } else {
> + gi2c->xfer_len = len;
> + gi2c->dma_addr = tx_dma;
> + gi2c->dma_buf = dma_buf;
> }
>
> if (!dma_buf) /* Get FIFO IRQ */
> writel_relaxed(1, se->base + SE_GENI_TX_WATERMARK_REG);
>
> + cur = gi2c->cur;
> time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
> if (!time_left)
> geni_i2c_abort_xfer(gi2c);
>
> - gi2c->cur_wr = 0;
> - if (dma_buf) {
> - if (gi2c->err)
> - geni_i2c_tx_fsm_rst(gi2c);
> - geni_se_tx_dma_unprep(se, tx_dma, len);
> - i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
> - }
> + geni_i2c_tx_msg_cleanup(gi2c, cur);
>
> return gi2c->err;
> }
--
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