Messages in this thread | | | Date | Tue, 22 Dec 2020 14:12:49 +0800 | From | Can Guo <> | Subject | Re: [PATCH v5 1/7] scsi: ufs: Add "wb_on" sysfs node to control WB on/off |
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On 2020-12-22 14:08, Stanley Chu wrote: > Hi Bean, > > On Wed, 2020-12-16 at 00:05 +0100, Bean Huo wrote: >> From: Bean Huo <beanhuo@micron.com> >> >> Currently UFS WriteBooster driver uses clock scaling up/down to set >> WB on/off, for the platform which doesn't support >> UFSHCD_CAP_CLK_SCALING, >> WB will be always on. Provide a sysfs attribute to enable/disable WB >> during runtime. Write 1/0 to "wb_on" sysfs node to enable/disable UFS >> WB. >> >> Reviewed-by: Avri Altman <avri.altman@wdc.com> >> Reviewed-by: Stanley Chu <stanley.chu@mediatek.com> >> Signed-off-by: Bean Huo <beanhuo@micron.com> >> --- >> drivers/scsi/ufs/ufs-sysfs.c | 41 >> ++++++++++++++++++++++++++++++++++++ >> drivers/scsi/ufs/ufshcd.c | 3 +-- >> drivers/scsi/ufs/ufshcd.h | 2 ++ >> 3 files changed, 44 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/scsi/ufs/ufs-sysfs.c >> b/drivers/scsi/ufs/ufs-sysfs.c >> index 08e72b7eef6a..f3ca3d6b82c4 100644 >> --- a/drivers/scsi/ufs/ufs-sysfs.c >> +++ b/drivers/scsi/ufs/ufs-sysfs.c >> @@ -189,6 +189,45 @@ static ssize_t auto_hibern8_store(struct device >> *dev, >> return count; >> } >> >> +static ssize_t wb_on_show(struct device *dev, struct device_attribute >> *attr, >> + char *buf) >> +{ >> + struct ufs_hba *hba = dev_get_drvdata(dev); >> + >> + return sysfs_emit(buf, "%d\n", hba->wb_enabled); >> +} >> + >> +static ssize_t wb_on_store(struct device *dev, struct >> device_attribute *attr, >> + const char *buf, size_t count) >> +{ >> + struct ufs_hba *hba = dev_get_drvdata(dev); >> + unsigned int wb_enable; >> + ssize_t res; >> + >> + if (ufshcd_is_clkscaling_supported(hba)) { >> + /* >> + * If the platform supports UFSHCD_CAP_CLK_SCALING, turn WB >> + * on/off will be done while clock scaling up/down. >> + */ >> + dev_warn(dev, "To control WB through wb_on is not allowed!\n"); >> + return -EOPNOTSUPP; >> + } >> + if (!ufshcd_is_wb_allowed(hba)) >> + return -EOPNOTSUPP; >> + >> + if (kstrtouint(buf, 0, &wb_enable)) >> + return -EINVAL; >> + >> + if (wb_enable != 0 && wb_enable != 1) >> + return -EINVAL; >> + >> + pm_runtime_get_sync(hba->dev); >> + res = ufshcd_wb_ctrl(hba, wb_enable); > > May this operation race with UFS shutdown flow? > > To be more clear, ufshcd_wb_ctrl() here may be executed after host > clock > is disabled by shutdown flow? > > If yes, we need to avoid it.
I have the same doubt - can user still access sysfs nodes after system starts to run shutdown routines? If yes, then we need to remove all UFS sysfs nodes in ufshcd_shutdown().
Thanks,
Can Guo.
> > Thanks, > Stanley Chu > >> + pm_runtime_put_sync(hba->dev); >> + >> + return res < 0 ? res : count; >> +} >> + >> static DEVICE_ATTR_RW(rpm_lvl); >> static DEVICE_ATTR_RO(rpm_target_dev_state); >> static DEVICE_ATTR_RO(rpm_target_link_state); >> @@ -196,6 +235,7 @@ static DEVICE_ATTR_RW(spm_lvl); >> static DEVICE_ATTR_RO(spm_target_dev_state); >> static DEVICE_ATTR_RO(spm_target_link_state); >> static DEVICE_ATTR_RW(auto_hibern8); >> +static DEVICE_ATTR_RW(wb_on); >> >> static struct attribute *ufs_sysfs_ufshcd_attrs[] = { >> &dev_attr_rpm_lvl.attr, >> @@ -205,6 +245,7 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] >> = { >> &dev_attr_spm_target_dev_state.attr, >> &dev_attr_spm_target_link_state.attr, >> &dev_attr_auto_hibern8.attr, >> + &dev_attr_wb_on.attr, >> NULL >> }; >> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> index e221add25a7e..5e1dcf4de67e 100644 >> --- a/drivers/scsi/ufs/ufshcd.c >> +++ b/drivers/scsi/ufs/ufshcd.c >> @@ -246,7 +246,6 @@ static inline int ufshcd_config_vreg_hpm(struct >> ufs_hba *hba, >> static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag); >> static int ufshcd_wb_buf_flush_enable(struct ufs_hba *hba); >> static int ufshcd_wb_buf_flush_disable(struct ufs_hba *hba); >> -static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable); >> static int ufshcd_wb_toggle_flush_during_h8(struct ufs_hba *hba, bool >> set); >> static inline void ufshcd_wb_toggle_flush(struct ufs_hba *hba, bool >> enable); >> static void ufshcd_hba_vreg_set_lpm(struct ufs_hba *hba); >> @@ -5351,7 +5350,7 @@ static void >> ufshcd_bkops_exception_event_handler(struct ufs_hba *hba) >> __func__, err); >> } >> >> -static int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable) >> +int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable) >> { >> int ret; >> u8 index; >> diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h >> index 9bb5f0ed4124..2a97006a2c93 100644 >> --- a/drivers/scsi/ufs/ufshcd.h >> +++ b/drivers/scsi/ufs/ufshcd.h >> @@ -1068,6 +1068,8 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba >> *hba, >> u8 *desc_buff, int *buff_len, >> enum query_opcode desc_op); >> >> +int ufshcd_wb_ctrl(struct ufs_hba *hba, bool enable); >> + >> /* Wrapper functions for safely calling variant operations */ >> static inline const char *ufshcd_get_var_name(struct ufs_hba *hba) >> {
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