在 2016/3/2 9:29, Jaehoon Chung 写道:
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....@rock-chips.com>
---

  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

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