Hi Kamal,
Kamal Dasu <kdasu.k...@gmail.com> wrote on Wed, 1 May 2019 13:46:15
-0400:
> If mtd_oops is in progress switch to polling for nand command completion
s/nand/NAND/
> interrupts and use PIO mode wihtout DMA so that the mtd_oops buffer can
> be completely written in the assinged nand partition.
What about:
"If mtd_oops is in progress, switch to polling during NAND command
completion instead of relying on DMA/interrupts so that the mtd_oops
buffer can be completely written in the assigned NAND partition."
> This is needed in
> cases where the panic does not happen on cpu0 and there is only one online
> CPU and the panic is not on cpu0.
"This is needed in case the panic does not happen on CPU0 and there is
only one online CPU."
I am not sure to understand the problem or how this can happen (and
be a problem). Have you met such issue already or is this purely
speculative?
>
> Signed-off-by: Kamal Dasu <kdasu.k...@gmail.com>
> ---
> drivers/mtd/nand/raw/brcmnand/brcmnand.c | 55
> ++++++++++++++++++++++++++++++--
> 1 file changed, 52 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> index 482c6f0..cfbe51a 100644
> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> @@ -823,6 +823,12 @@ static inline bool has_flash_dma(struct
> brcmnand_controller *ctrl)
> return ctrl->flash_dma_base;
> }
>
> +static inline void disable_flash_dma_xfer(struct brcmnand_controller *ctrl)
> +{
> + if (has_flash_dma(ctrl))
> + ctrl->flash_dma_base = 0;
> +}
> +
> static inline bool flash_dma_buf_ok(const void *buf)
> {
> return buf && !is_vmalloc_addr(buf) &&
> @@ -1237,15 +1243,58 @@ static void brcmnand_cmd_ctrl(struct nand_chip *chip,
> int dat,
> /* intentionally left blank */
> }
>
> +static bool is_mtd_oops_in_progress(void)
> +{
> + int i = 0;
> +
> +#ifdef CONFIG_MTD_OOPS
> + if (oops_in_progress && smp_processor_id()) {
> + int cpu = 0;
> +
> + for_each_online_cpu(cpu)
> + ++i;
> + }
> +#endif
> + return i == 1 ? true : false;
I suppose return (i == 1); is enough
> +}
> +
> +static bool brcmstb_nand_wait_for_completion(struct nand_chip *chip)
> +{
> + struct brcmnand_host *host = nand_get_controller_data(chip);
> + struct brcmnand_controller *ctrl = host->ctrl;
> + bool err = false;
> + int sts;
> +
> + if (is_mtd_oops_in_progress()) {
> + /* Switch to interrupt polling and PIO mode */
> + disable_flash_dma_xfer(ctrl);
> + sts = bcmnand_ctrl_poll_status(ctrl, NAND_CTRL_RDY |
> + NAND_STATUS_READY,
> + NAND_CTRL_RDY |
> + NAND_STATUS_READY, 0);
> + err = (sts < 0) ? true : false;
> + } else {
> + unsigned long timeo = msecs_to_jiffies(
> + NAND_POLL_STATUS_TIMEOUT_MS);
> + /* wait for completion interrupt */
> + sts = wait_for_completion_timeout(&ctrl->done, timeo);
> + err = (sts <= 0) ? true : false;
> + }
> +
> + return err;
> +}
> +
> static int brcmnand_waitfunc(struct nand_chip *chip)
> {
> struct brcmnand_host *host = nand_get_controller_data(chip);
> struct brcmnand_controller *ctrl = host->ctrl;
> - unsigned long timeo = msecs_to_jiffies(100);
> + bool err = false;
>
> dev_dbg(ctrl->dev, "wait on native cmd %d\n", ctrl->cmd_pending);
> - if (ctrl->cmd_pending &&
> - wait_for_completion_timeout(&ctrl->done, timeo) <= 0) {
What about the wait_for_completion_timeout() call in brcmnand_write()?
> + if (ctrl->cmd_pending)
> + err = brcmstb_nand_wait_for_completion(chip);
> +
> + if (err) {
> u32 cmd = brcmnand_read_reg(ctrl, BRCMNAND_CMD_START)
> >> brcmnand_cmd_shift(ctrl);
>
Thanks,
Miquèl
