iommu/amd: Expicitly enable CNTRL.EPHEn bit in resume path

JIRA: https://issues.redhat.com/browse/RHEL-78704
Upstream Status: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

commit ef75966
Author: Vasant Hegde <vasant.hegde@amd.com>
Date:   Mon Jan 27 09:44:11 2025 +0000

    iommu/amd: Expicitly enable CNTRL.EPHEn bit in resume path

    With recent kernel, AMDGPU failed to resume after suspend on certain laptop.

    Sample log:
    -----------
    Nov 14 11:52:19 Thinkbook kernel: iommu ivhd0: AMD-Vi: Event logged [ILLEGAL_DEV_TABLE_ENTRY device=0000:06:00.0 pasid=0x00000 address=0x135300000 flags=0x0080]
    Nov 14 11:52:19 Thinkbook kernel: AMD-Vi: DTE[0]: 7d90000000000003
    Nov 14 11:52:19 Thinkbook kernel: AMD-Vi: DTE[1]: 0000100103fc0009
    Nov 14 11:52:19 Thinkbook kernel: AMD-Vi: DTE[2]: 2000000117840013
    Nov 14 11:52:19 Thinkbook kernel: AMD-Vi: DTE[3]: 0000000000000000

    This is because in resume path, CNTRL[EPHEn] is not set. Fix this by
    setting CNTRL[EPHEn] to 1 in resume path if EFR[EPHSUP] is set.

    Note
      May be better approach is to save the control register in suspend path
      and restore it in resume path instead of trying to set indivisual
      bits. We will have separate patch for that.

    Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219499
    Fixes: c4cb231 ("iommu/amd: Add support for enable/disable IOPF")
    Tested-by: Hamish McIntyre-Bhatty <kernel-bugzilla@regd.hamishmb.com>
    Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
    Link: https://lore.kernel.org/r/20250127094411.5931-1-vasant.hegde@amd.com
    Signed-off-by: Joerg Roedel <jroedel@suse.de>

(cherry picked from commit ef75966)
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Author: snits

drivers/iommu/amd/amd_iommu_types.h

@@ -175,6 +175,7 @@
 #define CONTROL_GAM_EN		25
 #define CONTROL_GALOG_EN	28
 #define CONTROL_GAINT_EN	29
+#define CONTROL_EPH_EN		45
 #define CONTROL_XT_EN		50
 #define CONTROL_INTCAPXT_EN	51
 #define CONTROL_IRTCACHEDIS	59

drivers/iommu/amd/init.c

@@ -2653,6 +2653,10 @@ static void iommu_init_flags(struct amd_iommu *iommu)
 
 	/* Set IOTLB invalidation timeout to 1s */
 	iommu_set_inv_tlb_timeout(iommu, CTRL_INV_TO_1S);
+
+	/* Enable Enhanced Peripheral Page Request Handling */
+	if (check_feature(FEATURE_EPHSUP))
+		iommu_feature_enable(iommu, CONTROL_EPH_EN);
 }
 
 static void iommu_apply_resume_quirks(struct amd_iommu *iommu)