ufs: add UFS power management support

Hello Subhash Jadavani,

The patch 57d104c153d3: "ufs: add UFS power management support" from Sep 25, 2014, leads to the following static checker warning:

drivers/scsi/ufs/ufshcd.c:4746 ufshcd_link_state_transition()
warn: we tested 'check_for_bkops' before and it was 'true'

drivers/scsi/ufs/ufshcd.c
4734 if (req_link_state == UIC_LINK_HIBERN8_STATE) {
4735 ret = ufshcd_uic_hibern8_enter(hba);
4736 if (!ret)
4737 ufshcd_set_link_hibern8(hba);
4738 else
4739 goto out;
4740 }
4741 /*

  4742           * If autobkops is enabled, link can't be turned off because
  4743           * turning off the link would also turn off the device.
  4744           */
  4745          else if ((req_link_state == UIC_LINK_OFF_STATE) &&
  4746                     (!check_for_bkops || (check_for_bkops &&
                                                 ^^^^^^^^^^^^^^^

Not needed.

4747 !hba->auto_bkops_enabled))) {
4748 /*

  4749                   * Change controller state to "reset state" which
  4750                   * should also put the link in off/reset state
  4751                   */
  4752                  ufshcd_hba_stop(hba);
  4753                  /*
  4754                   * TODO: Check if we need any delay to make sure that
  4755                   * controller is reset
  4756                   */

4757 ufshcd_set_link_off(hba);
4758 }
4759
4760 out:
4761 return ret;
4762 }

regards,
dan carpenter

Hi Dan,
This seem like a false alarm, please let me know if it requires a fix.

Thanks,
Dolev

Qualcomm Israel, on behalf of Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, 
a Linux Foundation Collaborative Project 

-----Original Message-----
From: Dan Carpenter [mailto:[email protected]]
Sent: Thursday, October 02, 2014 6:31 PM
To: [email protected]
Cc: [email protected]
Subject: re: ufs: add UFS power management support

Hello Subhash Jadavani,

The patch 57d104c153d3: "ufs: add UFS power management support" from Sep 25, 2014, leads to the following static checker warning:

drivers/scsi/ufs/ufshcd.c:4746 ufshcd_link_state_transition()
warn: we tested 'check_for_bkops' before and it was 'true'

drivers/scsi/ufs/ufshcd.c
4734 if (req_link_state == UIC_LINK_HIBERN8_STATE) {
4735 ret = ufshcd_uic_hibern8_enter(hba);
4736 if (!ret)
4737 ufshcd_set_link_hibern8(hba);
4738 else
4739 goto out;
4740 }
4741 /*

  4742           * If autobkops is enabled, link can't be turned off because
  4743           * turning off the link would also turn off the device.
  4744           */
  4745          else if ((req_link_state == UIC_LINK_OFF_STATE) &&
  4746                     (!check_for_bkops || (check_for_bkops &&
                                                 ^^^^^^^^^^^^^^^ Not needed.

4747 !hba->auto_bkops_enabled))) {
4748 /*

  4749                   * Change controller state to "reset state" which
  4750                   * should also put the link in off/reset state
  4751                   */

4752 ufshcd_hba_stop(hba);
4753 /*
4754 * TODO: Check if we need any delay to make sure
that
4755 * controller is reset
4756 */
4757 ufshcd_set_link_off(hba);
4758 }
4759
4760 out:
4761 return ret;
4762 }

regards,
dan carpenter

It may not indicate a bug, but it is correct in that the code could be re-written:

Old:

	else if ((req_link_state == UIC_LINK_OFF_STATE) &&
		(!check_for_bkops || (check_for_bkops &&
		!hba->auto_bkops_enabled))) {

Proposed:

	else if ((req_link_state == UIC_LINK_OFF_STATE) &&
		 (!check_for_bkops || !hba->auto_bkops_enabled)) {

Those two are the same.

regards,
dan carpenter