[PATCHv5 3/4] sdhci-s3c: add support for new card detection methods (driver part)
Marek Szyprowski
m.szyprowski at samsung.com
Thu Jul 29 01:40:03 EDT 2010
Hello,
On Wednesday, July 28, 2010 7:03 PM Ben Dooks wrote:
> On 28/07/10 15:19, Marek Szyprowski wrote:
> > On some Samsung SoCs not all SDHCI controllers have card detect (CD)
> > line. For some embedded designs it is not even needed, because ususally
> > the device (like SDIO flash memory or wifi controller) is permanently
> > wired to the controller. There are also systems which have a card detect
> > line connected to some of the external interrupt lines or the presence
> > of the card depends on some other actions (like enabling a power
> > regulator).
> >
> > This patch adds support for all these cases. The following card
> > detection methods are possible:
> >
> > 1. internal sdhci host card detect line
> > 2. external event
> > 3. external gpio interrupt
> > 4. no card detect line, controller will poll for the card
> > 5. no card detect line, card is permanently wired to the controller
> > (once detected host won't poll it any more)
> >
> > By default, all existing code would use method #1, what is compatible
> > with the previous version of the driver.
> >
> > In case of external event, two callbacks must be provided in platdata:
> > ext_cd_init and ext_cd_cleanup. Both of them get a callback to a
> > function that notifies the s3c-sdhci host contoller as their argument.
> > That callback function should be called from the even dispatcher to let
> > host notice the card insertion/removal.
> >
> > In case of external gpio interrupt, a gpio pin number must be provided
> > in platdata (ext_cd_gpio parameter), as well as the information about
> > the polarity of that gpio pin (ext_cd_gpio_invert). By default
> > (ext_cd_gpio_invert == 0) gpio value 0 means 'card has been removed',
> > but this can be changed to 'card has been removed' when
> > ext_cd_gpio_invert == 1.
> >
> > This patch adds all required changes to sdhci-s3c driver.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> > Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
> > ---
> >
> > Changes since V4:
> > - adapted to threaded irq approach in sdhci driver
> > - rebased onto latest -mm kernel tree
> > - fixed problem when gpio-base card detection was not called on driver
> > init
> >
> > Changes since V3:
> > - renamed patch to avoid confusion with the patch for the s3c-sdhci
> > platform changes - added "(driver part)" in subject
> >
> > Changes since V2:
> > According to Andrew Morton's suggestion local_irq_save() call in the
> > sdhci_s3c_notify_change function has been replaced by spin_lock_irqsave
> > (host driver already has a spinlock that is used for protecting internal
> > state of the driver).
> >
> > Changes since V1:
> > - added support for gpio external interrupt card based detect method
> > directly to sdhci-s3c driver
> >
> > ---
> > drivers/mmc/host/sdhci-s3c.c | 78
> ++++++++++++++++++++++++++++++++++++++++++
> > drivers/mmc/host/sdhci.c | 47 ++++++++++++++-----------
> > drivers/mmc/host/sdhci.h | 1 +
> > 3 files changed, 106 insertions(+), 20 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
> > index 9938ded..606e695 100644
> > --- a/drivers/mmc/host/sdhci-s3c.c
> > +++ b/drivers/mmc/host/sdhci-s3c.c
> > @@ -18,6 +18,7 @@
> > #include <linux/slab.h>
> > #include <linux/clk.h>
> > #include <linux/io.h>
> > +#include <linux/gpio.h>
> >
> > #include <linux/mmc/host.h>
> >
> > @@ -44,6 +45,8 @@ struct sdhci_s3c {
> > struct resource *ioarea;
> > struct s3c_sdhci_platdata *pdata;
> > unsigned int cur_clk;
> > + int ext_cd_irq;
> > + int ext_cd_gpio;
> >
> > struct clk *clk_io;
> > struct clk *clk_bus[MAX_BUS_CLK];
> > @@ -235,6 +238,36 @@ static struct sdhci_ops sdhci_s3c_ops = {
> > .get_min_clock = sdhci_s3c_get_min_clock,
> > };
> >
> > +static void sdhci_s3c_notify_change(struct platform_device *dev, int
> state)
> > +{
> > + struct sdhci_host *host = platform_get_drvdata(dev);
> > + if (host) {
> > + mutex_lock(&host->lock);
> > + if (state) {
> > + dev_dbg(&dev->dev, "card inserted.\n");
> > + host->flags &= ~SDHCI_DEVICE_DEAD;
> > + host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> > + sdhci_card_detect(host);
> > + } else {
> > + dev_dbg(&dev->dev, "card removed.\n");
> > + host->flags |= SDHCI_DEVICE_DEAD;
> > + host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> > + sdhci_card_detect(host);
> > + }
> > + mutex_unlock(&host->lock);
> > + }
> > +}
> > +
> > +static irqreturn_t sdhci_s3c_gpio_card_detect_thread(int irq, void
> *dev_id)
> > +{
> > + struct sdhci_s3c *sc = dev_id;
> > + int status = gpio_get_value(sc->ext_cd_gpio);
> > + if (sc->pdata->ext_cd_gpio_invert)
> > + status = !status;
>
> maybe move the invert into sdhci_s3c_notify_change()
IMHO this is not a good idea. pdata->ext_cd_gpio_invert is used only for
GPIO-type card detection. External callback-based card detection can perform
similar inversion by itself, no need to duplicate it in sdhci-s3c driver.
>
> > + sdhci_s3c_notify_change(sc->pdev, status);
> > + return IRQ_HANDLED;
> > +}
> > +
> > static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
> > {
> > struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;
> > @@ -272,6 +305,7 @@ static int __devinit sdhci_s3c_probe(struct
> platform_device *pdev)
> > sc->host = host;
> > sc->pdev = pdev;
> > sc->pdata = pdata;
> > + sc->ext_cd_gpio = -1;
> >
> > platform_set_drvdata(pdev, host);
> >
> > @@ -355,6 +389,13 @@ static int __devinit sdhci_s3c_probe(struct
> platform_device *pdev)
> > * SDHCI block, or a missing configuration that needs to be set. */
> > host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ;
> >
> > + if (pdata->cd_type == S3C_SDHCI_CD_NONE ||
> > + pdata->cd_type == S3C_SDHCI_CD_PERMANENT)
> > + host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> > +
> > + if (pdata->cd_type == S3C_SDHCI_CD_PERMANENT)
> > + host->mmc->caps = MMC_CAP_NONREMOVABLE;
> > +
> > host->quirks |= (SDHCI_QUIRK_32BIT_DMA_ADDR |
> > SDHCI_QUIRK_32BIT_DMA_SIZE);
> >
> > @@ -367,6 +408,33 @@ static int __devinit sdhci_s3c_probe(struct
> platform_device *pdev)
> > goto err_add_host;
> > }
> >
> > + /* pdata->ext_cd_init might call sdhci_s3c_notify_change immediately,
> > + so it can be called only after sdhci_add_host() */
> > + if (pdata->cd_type == S3C_SDHCI_CD_EXTERNAL && pdata->ext_cd_init)
> > + pdata->ext_cd_init(&sdhci_s3c_notify_change);
>
> do we really need a callback for this?
Yes, there are cases that will use it. An example is a wifi sdio card,
permanently wired to sdhci controller, enabled/disabled by some rfkill glue.
This glue enables power regulators and notifies sdhci driver that the card
has been 'inserted' or 'removed'. This saves some power as otherwise sdhci
driver would need to pool for the card presence.
> > +
> > + if (pdata->cd_type == S3C_SDHCI_CD_GPIO &&
> > + gpio_is_valid(pdata->ext_cd_gpio)) {
> > + int status;
> > +
> > + gpio_request(pdata->ext_cd_gpio, "SDHCI EXT CD");
> > + sc->ext_cd_gpio = pdata->ext_cd_gpio;
> > +
> > + sc->ext_cd_irq = gpio_to_irq(pdata->ext_cd_gpio);
> > + if (sc->ext_cd_irq &&
> > + request_threaded_irq(sc->ext_cd_irq, NULL,
> sdhci_s3c_gpio_card_detect_thread,
> > + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> > + dev_name(&pdev->dev), sc)) {
> > + dev_err(&pdev->dev, "cannot request irq for card
> detect\n");
> > + sc->ext_cd_irq = 0;
> > + }
> > +
> > + status = gpio_get_value(sc->ext_cd_gpio);
> > + if (sc->pdata->ext_cd_gpio_invert)
> > + status = !status;
> > + sdhci_s3c_notify_change(sc->pdev, status);
> > + }
> > +
> > return 0;
> >
> > err_add_host:
> > @@ -391,10 +459,20 @@ static int __devinit sdhci_s3c_probe(struct
> platform_device *pdev)
> >
> > static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
> > {
> > + struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;
> > struct sdhci_host *host = platform_get_drvdata(pdev);
> > struct sdhci_s3c *sc = sdhci_priv(host);
> > int ptr;
> >
> > + if (pdata->cd_type == S3C_SDHCI_CD_EXTERNAL && pdata->ext_cd_cleanup)
> > + pdata->ext_cd_cleanup(&sdhci_s3c_notify_change);
> > +
> > + if (sc->ext_cd_irq)
> > + free_irq(sc->ext_cd_irq, sc);
> > +
> > + if (sc->ext_cd_gpio != -1)
> > + gpio_free(sc->ext_cd_gpio);
> > +
> > sdhci_remove_host(host, 1);
> >
> > for (ptr = 0; ptr < 3; ptr++) {
> > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> > index 682b285..aa82344 100644
> > --- a/drivers/mmc/host/sdhci.c
> > +++ b/drivers/mmc/host/sdhci.c
> > @@ -1244,26 +1244,6 @@ static const struct mmc_host_ops sdhci_ops = {
> > *
> *
> >
> \**************************************************************************
> ***/
> >
> > -static void sdhci_card_detect(struct sdhci_host *host)
> > -{
> > - if (!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT)) {
> > - if (host->mrq) {
> > - printk(KERN_ERR "%s: Card removed during transfer!\n",
> > - mmc_hostname(host->mmc));
> > - printk(KERN_ERR "%s: Resetting controller.\n",
> > - mmc_hostname(host->mmc));
> > -
> > - sdhci_reset(host, SDHCI_RESET_CMD);
> > - sdhci_reset(host, SDHCI_RESET_DATA);
> > -
> > - host->mrq->cmd->error = -ENOMEDIUM;
> > - schedule_work(&host->finish_work);
> > - }
> > - }
> > -
> > - mmc_detect_change(host->mmc, msecs_to_jiffies(200));
> > -}
> > -
> > static void sdhci_finish_work(struct work_struct *wk)
> > {
> > struct sdhci_host *host;
> > @@ -1627,6 +1607,33 @@ EXPORT_SYMBOL_GPL(sdhci_resume_host);
> >
> >
> /**************************************************************************
> ***\
> > *
> *
> > + * Implementation dependent callbacks
> *
> > + *
> *
> >
> +\*************************************************************************
> ****/
> > +
> > +void sdhci_card_detect(struct sdhci_host *host)
> > +{
> > + if (!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT)) {
> > + if (host->mrq) {
> > + printk(KERN_ERR "%s: Card removed during transfer!\n",
> > + mmc_hostname(host->mmc));
> > + printk(KERN_ERR "%s: Resetting controller.\n",
> > + mmc_hostname(host->mmc));
> > +
> > + sdhci_reset(host, SDHCI_RESET_CMD);
> > + sdhci_reset(host, SDHCI_RESET_DATA);
> > +
> > + host->mrq->cmd->error = -ENOMEDIUM;
> > + schedule_work(&host->finish_work);
> > + }
> > + }
> > +
> > + mmc_detect_change(host->mmc, msecs_to_jiffies(200));
> > +}
> > +EXPORT_SYMBOL_GPL(sdhci_card_detect);
>
> somehow this function seems to have been changed without a lot of
> obvious changes?
I've just moved this function out of 'workers section' to the new
'implementation dependent callbacks' section to make it easier to read the code.
The function itself has been modified when sdhci driver has been converted to
use threaded irqs rather than tasklets.
I you think that it would be better to leave the function in the place where it
was, just let me know.
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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