Re: [PATCH] mmc: dw_mmc-rockchip: fix failing to mount partition with "discard"

[Shawn Lin]

å 2016/3/2 9:29, Jaehoon Chung åé:
> Hi Shawn.
>
> On 03/01/2016 04:12 PM, Shawn Lin wrote:
> > Without MMC_CAP_ERASE support, we fail to mount partition
> > with "discard" option since mmc_queue_setup_discard is limited
> > for checking mmc_can_erase. Without doing mmc_queue_setup_discard,
> > blk_queue_discard fails to test QUEUE_FLAG_DISCARD flag, so we get
> > the following log from f2fs(actually similar to other file system):
> >
> > mounting with "discard" option, but the device does not support discard
>
> We can enable MMC_CAP_ERASE by default, since other SoC also needs this capability.
> I had sent some patch for enabling by default, but at that time i didn't remember why not enabled by default.
> I will check that reason..and share the information.

Hi Jaehoon,

Thanks for checking that. I didn't notice this part of code either until
I began to develop f2fs last month.
yes, I can't find any reasons not to enable it for dw_mmc because I look
more into dwmmc-databooks to see if any version of IP can't support
ERASE/TRIM command, and find none of them. So, enabling it by default is
safe.

> Best Regards,
> Jaehoon Chung
>
> > Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> > ---
> >
> >   drivers/mmc/host/dw_mmc-rockchip.c | 9 +++++++++
> >   1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/mmc/host/dw_mmc-rockchip.c b/drivers/mmc/host/dw_mmc-rockchip.c
> > index 84e50f3..2eda118 100644
> > --- a/drivers/mmc/host/dw_mmc-rockchip.c
> > +++ b/drivers/mmc/host/dw_mmc-rockchip.c
> > @@ -234,11 +234,20 @@ static int dw_mci_rockchip_init(struct dw_mci *host)
> >   	return 0;
> >   }
> >
> > +/* Common capabilities of RK3288 SoC */
> > +static unsigned long dw_mci_rk3288_dwmmc_caps[4] = {
> > +	MMC_CAP_ERASE,
> > +	MMC_CAP_ERASE,
> > +	MMC_CAP_ERASE,
> > +	MMC_CAP_ERASE,
> > +};
> > +
> >   static const struct dw_mci_drv_data rk2928_drv_data = {
> >   	.init			= dw_mci_rockchip_init,
> >   };
> >
> >   static const struct dw_mci_drv_data rk3288_drv_data = {
> > +	.caps			= dw_mci_rk3288_dwmmc_caps,
> >   	.set_ios		= dw_mci_rk3288_set_ios,
> >   	.execute_tuning		= dw_mci_rk3288_execute_tuning,
> >   	.parse_dt		= dw_mci_rk3288_parse_dt,


--
Best Regards
Shawn Lin