From a115b29aaa66d3dfe5d68fd47757b6bb1218bfb1 Mon Sep 17 00:00:00 2001 From: Subhash Jadavani Date: Fri, 24 Mar 2017 14:44:01 -0700 Subject: [PATCH] scsi: ufs: fix error handing during hibern8 enter MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During clock gating (ufshcd_gate_work()), we first put the link hibern8 by calling ufshcd_uic_hibern8_enter() and if ufshcd_uic_hibern8_enter() returns success (0) then we gate all the clocks. Now let’s zoom in to what ufshcd_uic_hibern8_enter() does internally: It calls __ufshcd_uic_hibern8_enter() which on detecting the LINERESET, initiates the full recovery and puts the link back to highest HS gear and returns success (0) to ufshcd_uic_hibern8_enter() which is the issue as link is still in active state due to recovery! Now ufshcd_uic_hibern8_enter() returns success to ufshcd_gate_work() and hence it goes ahead with gating the UFS clock while link is still in active state hence I believe controller would raise UIC error interrupts. But when we service the interrupt, clocks might have already been disabled! This change fixes for this by returning failure from __ufshcd_uic_hibern8_enter() if recovery succeeds as link is still not in hibern8, upon receiving the error ufshcd_hibern8_enter() would initiate retry to put the link state back into hibern8. Change-Id: Ib550fb791fa4c582b8f2d317a7f5f7594acb0872 Signed-off-by: Subhash Jadavani --- drivers/scsi/ufs/ufshcd.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 3e858015813f..79bb3337ba36 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -4289,15 +4289,25 @@ static int __ufshcd_uic_hibern8_enter(struct ufs_hba *hba) * mode hence full reinit is required to move link to HS speeds. */ if (ret || hba->full_init_linereset) { + int err; + hba->full_init_linereset = false; ufshcd_update_error_stats(hba, UFS_ERR_HIBERN8_ENTER); dev_err(hba->dev, "%s: hibern8 enter failed. ret = %d", __func__, ret); /* - * If link recovery fails then return error so that caller - * don't retry the hibern8 enter again. + * If link recovery fails then return error code (-ENOLINK) + * returned ufshcd_link_recovery(). + * If link recovery succeeds then return -EAGAIN to attempt + * hibern8 enter retry again. */ - ret = ufshcd_link_recovery(hba); + err = ufshcd_link_recovery(hba); + if (err) { + dev_err(hba->dev, "%s: link recovery failed", __func__); + ret = err; + } else { + ret = -EAGAIN; + } } else { dev_dbg(hba->dev, "%s: Hibern8 Enter at %lld us", __func__, ktime_to_us(ktime_get())); @@ -4314,8 +4324,8 @@ int ufshcd_uic_hibern8_enter(struct ufs_hba *hba) ret = __ufshcd_uic_hibern8_enter(hba); if (!ret) goto out; - /* Unable to recover the link, so no point proceeding */ - if (ret == -ENOLINK) + else if (ret != -EAGAIN) + /* Unable to recover the link, so no point proceeding */ BUG(); } out: