Hi Shimoda-san
Thanks for an update. Sorry it took me so long to get down to reviewing
it. I looked at it originally and I knew, I would need a significant time
this time to look and think about it, so, I had to postpone. This looks
much better already, thanks! The flow is already correct, but I think it
might be possible to improve it further. Please, see below.
On Tue, 18 Jun 2013, Shimoda, Yoshihiro wrote:
> This patch adds SET_BLOCK_COUNT(CMD23) support to sh_mmcif driver.
> If we add MMC_CAP_CMD23 to ".caps" of sh_mmcif_plat_data, the mmc
> core driver will use CMD23. Then, the sh_mmcif driver can use
> Reliable Write feature.
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> ---
> about v2:
> - remove the wait_for_completion() to process the .request() asynchronously.
>
> drivers/mmc/host/sh_mmcif.c | 64 +++++++++++++++++++++++++++++++++++++++---
> 1 files changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
> index 8ef5efa..8f66532 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
> @@ -223,7 +223,8 @@ enum mmcif_wait_for {
>
> struct sh_mmcif_host {
> struct mmc_host *mmc;
> - struct mmc_request *mrq;
> + struct mmc_request *mrq; /* current mmc_request pointer */
> + struct mmc_request *mrq_orig; /* original .request()'s pointer */
> struct platform_device *pd;
> struct clk *hclk;
> unsigned int clk;
> @@ -244,6 +245,7 @@ struct sh_mmcif_host {
> bool power;
> bool card_present;
> struct mutex thread_lock;
> + struct mmc_request mrq_sbc; /* mmc_request for SBC */
I don't think we'll need this eventually.
>
> /* DMA support */
> struct dma_chan *chan_rx;
> @@ -802,7 +804,11 @@ static u32 sh_mmcif_set_cmd(struct sh_mmcif_host *host,
> tmp |= CMD_SET_DWEN;
> /* CMLTE/CMD12EN */
> if (opc == MMC_READ_MULTIPLE_BLOCK || opc == MMC_WRITE_MULTIPLE_BLOCK) {
> - tmp |= CMD_SET_CMLTE | CMD_SET_CMD12EN;
> + /* If SBC, we don't use CMD12(STOP) */
> + if (mrq->sbc)
> + tmp |= CMD_SET_CMLTE;
> + else
> + tmp |= CMD_SET_CMLTE | CMD_SET_CMD12EN;
> sh_mmcif_bitset(host, MMCIF_CE_BLOCK_SET,
> data->blocks << 16);
> }
> @@ -936,9 +942,27 @@ static void sh_mmcif_request(struct mmc_host *mmc, struct mmc_request *mrq)
> break;
> }
>
> - host->mrq = mrq;
> + if (mrq->sbc) {
Ok, this is an entry point, you have to act here, agree. But how about the
following: we add a new WAIT state: MMCIF_WAIT_FOR_SBC and use that one
inside sh_mmcif_start_cmd() instead of MMCIF_WAIT_FOR_CMD in the SBC case?
Then maybe you won't need to change sh_mmcif_request() at all or almost at
all:
> + /* Store original mrq to mrq_orig */
> + host->mrq_orig = mrq;
> +
> + /* Copy original mrq data to mrq_sbc */
> + host->mrq_sbc = *mrq;
>
> - sh_mmcif_start_cmd(host, mrq);
this call might change, see later.
> + /* Switch the mrq_sbc.cmd for SBC */
> + host->mrq_sbc.cmd = mrq->sbc;
> + host->mrq_sbc.sbc = NULL;
> + host->mrq_sbc.data = NULL;
> + host->mrq_sbc.stop = NULL;
> +
> + /* Set current mrq pointer to mrq_sbc */
> + host->mrq = &host->mrq_sbc;
> + } else {
> + /* Set current mrq pointer to original mrq */
> + host->mrq = mrq;
> + }
> +
> + sh_mmcif_start_cmd(host, host->mrq);
This will set "host->wait_for = MMCIF_WAIT_FOR_CMD"
> }
>
> static int sh_mmcif_clk_update(struct sh_mmcif_host *host)
> @@ -1212,13 +1236,35 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
Now, when we enter sh_mmcif_irqt() after an SBC command completion, we
still have "host->wait_for == MMCIF_WAIT_FOR_CMD" so we enter
sh_mmcif_end_cmd(), right? But you set mrq->data = NULL above, so, it just
(possibly) gets a response and returns. So far so good.
With the proposed MMCIF_WAIT_FOR_SBC you'll have something like
case MMCIF_WAIT_FOR_SBC:
wait = sh_mmcif_end_sbc(host);
break;
In sh_mmcif_end_sbc() you would do a similar to sh_mmcif_end_cmd() error
processing, maybe get a response (no idea, whether SBC has MMC_RSP_PRESENT
set), call sh_mmcif_start_cmd() again, but there now you have to take care
not to jump to the same state again, but to use MMCIF_WAIT_FOR_CMD this
time. So, your wait-assignment in sh_mmcif_start_cmd() would look like
if (mrq->sbc && host->wait_for != MMCIF_WAIT_FOR_SBC)
host->wait_for = MMCIF_WAIT_FOR_SBC;
else
host->wait_for = MMCIF_WAIT_FOR_CMD;
and return true.
> return IRQ_HANDLED;
> }
>
> + if (mrq->sbc && (mrq->cmd->opcode == MMC_WRITE_MULTIPLE_BLOCK) &&
> + (host->wait_for != MMCIF_WAIT_FOR_WRITE_END)) {
> + /* Wait for end of data phase */
> + host->wait_for = MMCIF_WAIT_FOR_WRITE_END;
> + sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MDTRANE);
> + schedule_delayed_work(&host->timeout_work, host->timeout);
> + mutex_unlock(&host->thread_lock);
> + return IRQ_HANDLED;
> + }
> +
> + if (mrq->sbc && (mrq->cmd->opcode == MMC_READ_MULTIPLE_BLOCK) &&
> + (host->wait_for != MMCIF_WAIT_FOR_READ_END)) {
> + /* Wait for end of data phase */
> + host->wait_for = MMCIF_WAIT_FOR_READ_END;
> + sh_mmcif_bitset(host, MMCIF_CE_INT_MASK, MASK_MBUFRE);
> + schedule_delayed_work(&host->timeout_work, host->timeout);
> + mutex_unlock(&host->thread_lock);
> + return IRQ_HANDLED;
> + }
Hm, this is interesting. Why do you need those? Currently we only wait for
read- and write-end conditions in single-block read- and write-operations,
but not in multi-block ones. With SBC you also want to wait for them in
the multi-block case. Is it really SBC-specific or maybe we have to do
this always? In either case I wouldn't add it here but to respective
state-handlers, called from the switch statement above. And if this is
indeed needed for all multi-block operations, this should be a separate
patch.
> +
> if (host->wait_for != MMCIF_WAIT_FOR_STOP) {
Currently you enter this path also after processing an SBC, which isn't
needed, but just happens to be harmless. If you use MMCIF_WAIT_FOR_SBC you
don't get here at all.
> struct mmc_data *data = mrq->data;
> if (!mrq->cmd->error && data && !data->error)
> data->bytes_xfered =
> data->blocks * data->blksz;
>
> - if (mrq->stop && !mrq->cmd->error && (!data || !data->error)) {
> + /* If SBC, we don't use CMD12(STOP) */
> + if (mrq->stop && !mrq->cmd->error && (!data || !data->error) &&
> + !mrq->sbc) {
> sh_mmcif_stop_cmd(host, mrq);
> if (!mrq->stop->error) {
> schedule_delayed_work(&host->timeout_work, host->timeout);
> @@ -1228,6 +1274,14 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
> }
> }
>
> + if ((mrq->cmd->opcode == MMC_SET_BLOCK_COUNT) && !mrq->cmd->error) {
This won't be needed.
> + /* Send the original .request() command */
> + host->mrq = host->mrq_orig;
> + sh_mmcif_start_cmd(host, host->mrq);
> + mutex_unlock(&host->thread_lock);
> + return IRQ_HANDLED;
> + }
> +
> host->wait_for = MMCIF_WAIT_FOR_REQUEST;
> host->state = STATE_IDLE;
> host->mrq = NULL;
> --
> 1.7.1
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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