scsi: ufs-mediatek: enable low-power mode for hibern8 state

In MediaTek Chipsets, UniPro link and ufshci can enter proprietary
low-power mode while link is in hibern8 state.

Link: https://lore.kernel.org/r/20200117035108.19699-4-stanley.chu@mediatek.com
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index d5194d0c4ef51f7a4f8cccba73d4922becc2eb30..f32f3f34f6d0ef22cc73277069b66d32bc11e0a2 100644 (file)
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -382,11 +382,60 @@ static void ufs_mtk_device_reset(struct ufs_hba *hba)
        dev_info(hba->dev, "device reset done\n");
 }
 
+static int ufs_mtk_link_set_hpm(struct ufs_hba *hba)
+{
+       int err;
+
+       err = ufshcd_hba_enable(hba);
+       if (err)
+               return err;
+
+       err = ufshcd_dme_set(hba,
+                            UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
+                            0);
+       if (err)
+               return err;
+
+       err = ufshcd_uic_hibern8_exit(hba);
+       if (!err)
+               ufshcd_set_link_active(hba);
+       else
+               return err;
+
+       err = ufshcd_make_hba_operational(hba);
+       if (err)
+               return err;
+
+       return 0;
+}
+
+static int ufs_mtk_link_set_lpm(struct ufs_hba *hba)
+{
+       int err;
+
+       err = ufshcd_dme_set(hba,
+                            UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
+                            1);
+       if (err) {
+               /* Resume UniPro state for following error recovery */
+               ufshcd_dme_set(hba,
+                              UIC_ARG_MIB_SEL(VS_UNIPROPOWERDOWNCONTROL, 0),
+                              0);
+               return err;
+       }
+
+       return 0;
+}
+
 static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 {
+       int err;
        struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 
        if (ufshcd_is_link_hibern8(hba)) {
+               err = ufs_mtk_link_set_lpm(hba);
+               if (err)
+                       return -EAGAIN;
                phy_power_off(host->mphy);
                ufs_mtk_setup_ref_clk(hba, false);
        }
@@ -397,10 +446,14 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 static int ufs_mtk_resume(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 {
        struct ufs_mtk_host *host = ufshcd_get_variant(hba);
+       int err;
 
        if (ufshcd_is_link_hibern8(hba)) {
                ufs_mtk_setup_ref_clk(hba, true);
                phy_power_on(host->mphy);
+               err = ufs_mtk_link_set_hpm(hba);
+               if (err)
+                       return err;
        }
 
        return 0;