RE: [PATCH v3 1/4] mmc: dw_mmc: Add "disable-wp" device tree property

[Seungwon Jeon <tgih.jun@samsung.com>]

Doug, Thanks to work.
Looks good to me with other patches.

Acked-by: Seungwon Jeon <tgih.jun@samsung.com>

On Friday, November 30, 2012, Doug Anderson wrote:
> The "disable-wp" property is used to specify that a given SD card slot
> doesn't have a concept of write protect.  This eliminates the need for
> special case code for SD slots that should never be write protected
> (like a micro SD slot or a dev board).
> 
> The dw_mmc driver is special in needing to specify "disable-wp"
> because the lack of a "wp-gpios" property means to use the special
> purpose write protect line.  On some other mmc devices the lack of
> "wp-gpios" means that write protect should be disabled.
> 
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
> Changes in v3:
> - New for this version of the patch series.  Chose "disable-wp" rather
>   than the discussed "broken-internal-wp" since it mapped more cleanly
>   to an existing quirk (and the only reason to specify that the
>   internal wp is broken is if you're disabling the write protect
>   anyway).
> 
>  .../devicetree/bindings/mmc/synopsis-dw-mshc.txt   |   12 +++++-
>  drivers/mmc/host/dw_mmc.c                          |   36 +++++++++++++++++++-
>  include/linux/mmc/dw_mmc.h                         |    4 ++
>  3 files changed, 49 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> index 06cd32d08..726fd21 100644
> --- a/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> +++ b/Documentation/devicetree/bindings/mmc/synopsis-dw-mshc.txt
> @@ -26,8 +26,16 @@ Required Properties:
>  	* bus-width: as documented in mmc core bindings.
> 
>  	* wp-gpios: specifies the write protect gpio line. The format of the
> -	  gpio specifier depends on the gpio controller. If the write-protect
> -	  line is not available, this property is optional.
> +	  gpio specifier depends on the gpio controller. If a GPIO is not used
> +	  for write-protect, this property is optional.
> +
> +	* disable-wp: If the wp-gpios property isn't present then (by default)
> +	  we'd assume that the write protect is hooked up directly to the
> +	  controller's special purpose write protect line (accessible via
> +	  the WRTPRT register).  However, it's possible that we simply don't
> +	  want write protect.  In that case specify 'disable-wp'.
> +	  NOTE: This property is not required for slots known to always
> +	  connect to eMMC or SDIO cards.
> 
>  Optional properties:
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 7342029..b47b1e9 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -74,6 +74,7 @@ struct idmac_desc {
>   * struct dw_mci_slot - MMC slot state
>   * @mmc: The mmc_host representing this slot.
>   * @host: The MMC controller this slot is using.
> + * @quirks: Slot-level quirks (DW_MCI_SLOT_QUIRK_XXX)
>   * @ctype: Card type for this slot.
>   * @mrq: mmc_request currently being processed or waiting to be
>   *	processed, or NULL when the slot is idle.
> @@ -88,6 +89,8 @@ struct dw_mci_slot {
>  	struct mmc_host		*mmc;
>  	struct dw_mci		*host;
> 
> +	int			quirks;
> +
>  	u32			ctype;
> 
>  	struct mmc_request	*mrq;
> @@ -828,7 +831,8 @@ static int dw_mci_get_ro(struct mmc_host *mmc)
>  	struct dw_mci_board *brd = slot->host->pdata;
> 
>  	/* Use platform get_ro function, else try on board write protect */
> -	if (brd->quirks & DW_MCI_QUIRK_NO_WRITE_PROTECT)
> +	if ((brd->quirks & DW_MCI_QUIRK_NO_WRITE_PROTECT) ||
> +	    (slot->quirks & DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT))
>  		read_only = 0;
>  	else if (brd->get_ro)
>  		read_only = brd->get_ro(slot->id);
> @@ -1788,6 +1792,30 @@ static struct device_node *dw_mci_of_find_slot_node(struct device *dev, u8 slot)
>  	return NULL;
>  }
> 
> +static struct dw_mci_of_slot_quirks {
> +	char *quirk;
> +	int id;
> +} of_slot_quirks[] = {
> +	{
> +		.quirk	= "disable-wp",
> +		.id	= DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT,
> +	},
> +};
> +
> +static int dw_mci_of_get_slot_quirks(struct device *dev, u8 slot)
> +{
> +	struct device_node *np = dw_mci_of_find_slot_node(dev, slot);
> +	int quirks = 0;
> +	int idx;
> +
> +	/* get quirks */
> +	for (idx = 0; idx < ARRAY_SIZE(of_slot_quirks); idx++)
> +		if (of_get_property(np, of_slot_quirks[idx].quirk, NULL))
> +			quirks |= of_slot_quirks[idx].id;
> +
> +	return quirks;
> +}
> +
>  /* find out bus-width for a given slot */
>  static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
>  {
> @@ -1803,6 +1831,10 @@ static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
>  	return bus_wd;
>  }
>  #else /* CONFIG_OF */
> +static int dw_mci_of_get_slot_quirks(struct device *dev, u8 slot)
> +{
> +	return 0;
> +}
>  static u32 dw_mci_of_get_bus_wd(struct device *dev, u8 slot)
>  {
>  	return 1;
> @@ -1831,6 +1863,8 @@ static int dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>  	slot->host = host;
>  	host->slot[id] = slot;
> 
> +	slot->quirks = dw_mci_of_get_slot_quirks(host->dev, slot->id);
> +
>  	mmc->ops = &dw_mci_ops;
>  	mmc->f_min = DIV_ROUND_UP(host->bus_hz, 510);
>  	mmc->f_max = host->bus_hz;
> diff --git a/include/linux/mmc/dw_mmc.h b/include/linux/mmc/dw_mmc.h
> index 34be4f4..24dc3a8 100644
> --- a/include/linux/mmc/dw_mmc.h
> +++ b/include/linux/mmc/dw_mmc.h
> @@ -212,6 +212,10 @@ struct dw_mci_dma_ops {
>  /* Write Protect detection not available */
>  #define DW_MCI_QUIRK_NO_WRITE_PROTECT		BIT(4)
> 
> +/* Slot level quirks */
> +/* This slot has no write protect */
> +#define DW_MCI_SLOT_QUIRK_NO_WRITE_PROTECT	BIT(0)
> +
>  struct dma_pdata;
> 
>  struct block_settings {
> --
> 1.7.7.3
> 
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