[PATCH 1/3] scsi: ufs: ufs-pci: Fix hibernate state transition for Intel MTL-like host controllers

[Adrian Hunter <adrian.hunter@intel.com>]

From: Archana Patni <archana.patni@intel.com>

UFSHCD core disables the UIC completion interrupt when issuing UIC
hibernation commands, and re-enables it afterwards if it was enabled to
start with, refer ufshcd_uic_pwr_ctrl(). For Intel MTL-like host
controllers, accessing the register to re-enable the interrupt disrupts the
state transition.

Use hibern8_notify variant operation to disable the interrupt during the
entire hibernation, thereby preventing the disruption.

Fixes: 4049f7acef3eb ("scsi: ufs: ufs-pci: Add support for Intel MTL")
Cc: stable@vger.kernel.org
Signed-off-by: Archana Patni <archana.patni@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/ufs/host/ufshcd-pci.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/ufs/host/ufshcd-pci.c b/drivers/ufs/host/ufshcd-pci.c
index 996387906aa1..af1c272eef1c 100644
--- a/drivers/ufs/host/ufshcd-pci.c
+++ b/drivers/ufs/host/ufshcd-pci.c
@@ -216,6 +216,32 @@ static int ufs_intel_lkf_apply_dev_quirks(struct ufs_hba *hba)
 	return ret;
 }
 
+static void ufs_intel_ctrl_uic_compl(struct ufs_hba *hba, bool enable)
+{
+	u32 set = ufshcd_readl(hba, REG_INTERRUPT_ENABLE);
+
+	if (enable)
+		set |= UIC_COMMAND_COMPL;
+	else
+		set &= ~UIC_COMMAND_COMPL;
+	ufshcd_writel(hba, set, REG_INTERRUPT_ENABLE);
+}
+
+static void ufs_intel_mtl_h8_notify(struct ufs_hba *hba,
+				    enum uic_cmd_dme cmd,
+				    enum ufs_notify_change_status status)
+{
+	/*
+	 * Disable UIC COMPL INTR to prevent access to UFSHCI after
+	 * checking HCS.UPMCRS
+	 */
+	if (status == PRE_CHANGE && cmd == UIC_CMD_DME_HIBER_ENTER)
+		ufs_intel_ctrl_uic_compl(hba, false);
+
+	if (status == POST_CHANGE && cmd == UIC_CMD_DME_HIBER_EXIT)
+		ufs_intel_ctrl_uic_compl(hba, true);
+}
+
 #define INTEL_ACTIVELTR		0x804
 #define INTEL_IDLELTR		0x808
 
@@ -533,6 +559,7 @@ static struct ufs_hba_variant_ops ufs_intel_mtl_hba_vops = {
 	.init			= ufs_intel_mtl_init,
 	.exit			= ufs_intel_common_exit,
 	.hce_enable_notify	= ufs_intel_hce_enable_notify,
+	.hibern8_notify		= ufs_intel_mtl_h8_notify,
 	.link_startup_notify	= ufs_intel_link_startup_notify,
 	.resume			= ufs_intel_resume,
 	.device_reset		= ufs_intel_device_reset,
-- 
2.48.1