Re: [PATCH 2/5] mmc: tmio: Provide separate interrupt handlers

Simon Horman
2011-08-16T07:59:29Z

On Tue, Aug 16, 2011 at 09:41:52AM +0200, Guennadi Liakhovetski wrote:
> On Tue, 16 Aug 2011, Simon Horman wrote:
>
> > Provide separate interrupt handlers which may be used by platforms where
> > SDHI has three interrupt sources.
>
> Yes, this looks much simpler and cleaner to me now, than 3 original
> patches. It might change a bit after you change your PATCH 1/5,
>
> >
> > This involves two key changes to the logic:
> > 1. Do not assume that only one interrupt has occurred.
> > In particular because tmio_mmc_irq() handles interrupts
> > from three sources. Also, because this allows
> > the logic to be simplified.
> > 2. Just ignore spurious interrupts.
> > Its not clear to me that they can ever occur.
> >
> > This patch also removes the commented-out handling of CRC and other errors.
> >
> > Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> > Cc: Magnus Damm <magnus.damm@gmail.com>
> > Signed-off-by: Simon Horman <horms@verge.net.au>
> >
> > ---
> >
> > * SDCARD portion tested on AP4/Mackerel
> > * SDIO portion untested
> >
> > v2
> > As suggested by Guennadi Liakhovetski
> > * Combine 3 patches into one
> > * Reduce the number of __tmio_..._irq() functions
> > * Rename "...card_access..." functions as "...sdcard..."
> > ---
> > drivers/mmc/host/tmio_mmc.h | 3 +
> > drivers/mmc/host/tmio_mmc_pio.c | 121 +++++++++++++++++++++++----------------
> > 2 files changed, 75 insertions(+), 49 deletions(-)
> >
> > diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
> > index 1cf8db5..3020f98 100644
> > --- a/drivers/mmc/host/tmio_mmc.h
> > +++ b/drivers/mmc/host/tmio_mmc.h
> > @@ -97,6 +97,9 @@ void tmio_mmc_do_data_irq(struct tmio_mmc_host *host);
> > void tmio_mmc_enable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
> > void tmio_mmc_disable_mmc_irqs(struct tmio_mmc_host *host, u32 i);
> > irqreturn_t tmio_mmc_irq(int irq, void *devid);
> > +irqreturn_t tmio_mmc_sdcard_irq(int irq, void *devid);
> > +irqreturn_t tmio_mmc_card_detect_irq(int irq, void *devid);
> > +irqreturn_t tmio_mmc_sdio_irq(int irq, void *devid);
> >
> > static inline char *tmio_mmc_kmap_atomic(struct scatterlist *sg,
> > unsigned long *flags)
> > diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
> > index c60b15f..e9640f2 100644
> > --- a/drivers/mmc/host/tmio_mmc_pio.c
> > +++ b/drivers/mmc/host/tmio_mmc_pio.c
> > @@ -547,45 +547,20 @@ out:
> > spin_unlock(&host->lock);
> > }
> >
> > -irqreturn_t tmio_mmc_irq(int irq, void *devid)
> > +static void tmio_mmc_card_irq_status(struct tmio_mmc_host *host,
> > + int *ireg, int *status)
> > {
> > - struct tmio_mmc_host *host = devid;
> > - struct mmc_host *mmc = host->mmc;
> > - struct tmio_mmc_data *pdata = host->pdata;
> > - unsigned int ireg, status;
> > - unsigned int sdio_ireg, sdio_status;
> > -
> > - pr_debug("MMC IRQ begin\n");
> > -
> > - status = sd_ctrl_read32(host, CTL_STATUS);
> > - ireg = status & TMIO_MASK_IRQ & ~host->sdcard_irq_mask;
> > + *status = sd_ctrl_read32(host, CTL_STATUS);
> > + *ireg = *status & TMIO_MASK_IRQ & ~host->sdcard_irq_mask;
> >
> > - sdio_ireg = 0;
> > - if (!ireg && pdata->flags & TMIO_MMC_SDIO_IRQ) {
> > - sdio_status = sd_ctrl_read16(host, CTL_SDIO_STATUS);
> > - host->sdio_irq_mask = sd_ctrl_read16(host, CTL_SDIO_IRQ_MASK);
> > - sdio_ireg = sdio_status & TMIO_SDIO_MASK_ALL &
> > - ~host->sdio_irq_mask;
> > -
> > - sd_ctrl_write16(host, CTL_SDIO_STATUS, sdio_status & ~TMIO_SDIO_MASK_ALL);
> > -
> > - if (sdio_ireg && !host->sdio_irq_enabled) {
> > - pr_warning("tmio_mmc: Spurious SDIO IRQ, disabling! 0x%04x 0x%04x 0x%04x\n",
> > - sdio_status, host->sdio_irq_mask, sdio_ireg);
> > - tmio_mmc_enable_sdio_irq(mmc, 0);
> > - goto out;
> > - }
> > -
> > - if (mmc->caps & MMC_CAP_SDIO_IRQ &&
> > - sdio_ireg & TMIO_SDIO_STAT_IOIRQ)
> > - mmc_signal_sdio_irq(mmc);
> > -
> > - if (sdio_ireg)
> > - goto out;
> > - }
> > + pr_debug_status(*status);
> > + pr_debug_status(*ireg);
> > +}
> >
> > - pr_debug_status(status);
> > - pr_debug_status(ireg);
> > +static void __tmio_mmc_card_detect_irq(struct tmio_mmc_host *host,
> > + int ireg, int status)
> > +{
> > + struct mmc_host *mmc = host->mmc;
> >
> > /* Card insert / remove attempts */
> > if (ireg & (TMIO_STAT_CARD_INSERT | TMIO_STAT_CARD_REMOVE)) {
> > @@ -595,43 +570,91 @@ irqreturn_t tmio_mmc_irq(int irq, void *devid)
> > ((ireg & TMIO_STAT_CARD_INSERT) && !mmc->card)) &&
> > !work_pending(&mmc->detect.work))
> > mmc_detect_change(host->mmc, msecs_to_jiffies(100));
> > - goto out;
> > }
> > +}
> >
> > - /* CRC and other errors */
> > -/* if (ireg & TMIO_STAT_ERR_IRQ)
> > - * handled |= tmio_error_irq(host, irq, stat);
> > - */
> > +irqreturn_t tmio_mmc_card_detect_irq(int irq, void *devid)
> > +{
> > + unsigned int ireg, status;
> > + struct tmio_mmc_host *host = devid;
> > +
> > + tmio_mmc_card_irq_status(host, &ireg, &status);
> > + __tmio_mmc_card_detect_irq(host, ireg, status);
> >
> > + return IRQ_HANDLED;
> > +}
> > +EXPORT_SYMBOL(tmio_mmc_card_detect_irq);
> > +
> > +void __tmio_mmc_sdcard_irq(struct tmio_mmc_host *host, int ireg, int status)
>
> "static" missing
>
> > +{
> > /* Command completion */
> > if (ireg & (TMIO_STAT_CMDRESPEND | TMIO_STAT_CMDTIMEOUT)) {
> > tmio_mmc_ack_mmc_irqs(host,
> > TMIO_STAT_CMDRESPEND |
> > TMIO_STAT_CMDTIMEOUT);
> > tmio_mmc_cmd_irq(host, status);
> > - goto out;
>
> Well, removing these goto's certainly changes behaviour - at least
> theoretically. Imagine entering the ISR with status = TMIO_STAT_CMDRESPEND
> | TMIO_STAT_DATAEND. Before your patch the driver would ack and process
> the TMIO_STAT_CMDRESPEND and return dropping the TMIO_STAT_DATAEND status.
> Anc we don't know whether a second interrupt would follow with
> TMIO_STAT_DATAEND set. After your patch the driver will ack and process
> both. Since this driver runs on a variaty of hardware, unless fixing a
> problem or really improving something, I would keep the original
> behaviour. So, I would rather keep those exit points - just put "return"
> there.

I specifically noted this change in the changelog, sorry if that wasn't
clear enough.

I will revert the behaviour as you suggest, although I suspect
that the new behaviour is correct.

> > }
> >
> > /* Data transfer */
> > if (ireg & (TMIO_STAT_RXRDY | TMIO_STAT_TXRQ)) {
> > tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_RXRDY | TMIO_STAT_TXRQ);
> > tmio_mmc_pio_irq(host);
> > - goto out;
> > }
> >
> > /* Data transfer completion */
> > if (ireg & TMIO_STAT_DATAEND) {
> > tmio_mmc_ack_mmc_irqs(host, TMIO_STAT_DATAEND);
> > tmio_mmc_data_irq(host);
> > - goto out;
> > }
> > +}
> > +
> > +irqreturn_t tmio_mmc_sdcard_irq(int irq, void *devid)
> > +{
> > + unsigned int ireg, status;
> > + struct tmio_mmc_host *host = devid;
> >
> > - pr_warning("tmio_mmc: Spurious irq, disabling! "
> > - "0x%08x 0x%08x 0x%08x\n", status, host->sdcard_irq_mask, ireg);
> > - pr_debug_status(status);
> > - tmio_mmc_disable_mmc_irqs(host, status & ~host->sdcard_irq_mask);
> > + tmio_mmc_card_irq_status(host, &ireg, &status);
> > + __tmio_mmc_sdcard_irq(host, ireg, status);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +EXPORT_SYMBOL(tmio_mmc_sdcard_irq);
> > +
> > +irqreturn_t tmio_mmc_sdio_irq(int irq, void *devid)
> > +{
> > + struct tmio_mmc_host *host = devid;
> > + struct mmc_host *mmc = host->mmc;
> > + struct tmio_mmc_data *pdata = host->pdata;
> > + unsigned int ireg, status;
> > +
> > + if (!(pdata->flags & TMIO_MMC_SDIO_IRQ))
> > + return IRQ_HANDLED;
> > +
> > + status = sd_ctrl_read16(host, CTL_SDIO_STATUS);
> > + ireg = status & TMIO_SDIO_MASK_ALL & ~host->sdcard_irq_mask;
> > +
> > + sd_ctrl_write16(host, CTL_SDIO_STATUS, status & ~TMIO_SDIO_MASK_ALL);
> > +
> > + if (mmc->caps & MMC_CAP_SDIO_IRQ && ireg & TMIO_SDIO_STAT_IOIRQ)
> > + mmc_signal_sdio_irq(mmc);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +EXPORT_SYMBOL(tmio_mmc_sdio_irq);
> > +
> > +irqreturn_t tmio_mmc_irq(int irq, void *devid)
> > +{
> > + struct tmio_mmc_host *host = devid;
> > + unsigned int ireg, status;
> > +
> > + pr_debug("MMC IRQ begin\n");
> > +
> > + tmio_mmc_card_irq_status(host, &ireg, &status);
> > + __tmio_mmc_card_detect_irq(host, ireg, status);
>
> Same here - I would return, if a card hot-plug event occurred.

Will do.

> > + __tmio_mmc_sdcard_irq(host, ireg, status);
>
> Ditto
>
> > +
> > + tmio_mmc_sdio_irq(irq, devid);
>
> Any specific reason, why you now process SDIO IRQs last?

I believe this is in keeping with the ordering implied by original code.

> >
> > -out:
> > return IRQ_HANDLED;
> > }
> > EXPORT_SYMBOL(tmio_mmc_irq);
> > --
> > 1.7.5.4
>
> Thanks
> Guennadi
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
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