Hi Stuart

On 7/15/2025 7:38 PM, Summers, Stuart wrote:
On Tue, 2025-07-15 at 16:17 +0530, Riana Tauro wrote:
Gfx device reports two classes of errors: uncorrectable and
correctable. Depending on the severity uncorrectable errors are
further
classified Non-Fatal and Fatal

Correctable and Non-Fatal errors: These errors are reported as MSI.
Bits in
the Master Interrupt Register indicate the class of the error.
The source of the error is then read from the Device Error Source
Register.

Fatal errors: These are reported as PCIe errors
When a PCIe error is asserted, the OS will perform a SBR (Secondary
Bus reset) which causes the driver to reload.
The error registers are sticky and the values are maintained through
SBR

Add basic support to handle these errors

Bspec: 50875, 53073, 53074, 53075, 53076

v2: Remove platform checks and print raw error value (Stuart)
     Format commit message (Umesh)

Cc: Stuart Summers <stuart.summ...@intel.com>
Co-developed-by: Himal Prasad Ghimiray
<himal.prasad.ghimi...@intel.com>
Signed-off-by: Himal Prasad Ghimiray
<himal.prasad.ghimi...@intel.com>
Signed-off-by: Riana Tauro <riana.ta...@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.rama...@intel.com>
---
  drivers/gpu/drm/xe/Makefile                |   1 +
  drivers/gpu/drm/xe/regs/xe_hw_error_regs.h |  15 +++
  drivers/gpu/drm/xe/regs/xe_irq_regs.h      |   1 +
  drivers/gpu/drm/xe/xe_hw_error.c           | 106
+++++++++++++++++++++
  drivers/gpu/drm/xe/xe_hw_error.h           |  15 +++
  drivers/gpu/drm/xe/xe_irq.c                |   4 +
  6 files changed, 142 insertions(+)
  create mode 100644 drivers/gpu/drm/xe/regs/xe_hw_error_regs.h
  create mode 100644 drivers/gpu/drm/xe/xe_hw_error.c
  create mode 100644 drivers/gpu/drm/xe/xe_hw_error.h

diff --git a/drivers/gpu/drm/xe/Makefile
b/drivers/gpu/drm/xe/Makefile
index 07c71a29963d..02f73dffec55 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -80,6 +80,7 @@ xe-y += xe_bb.o \
         xe_hw_engine.o \
         xe_hw_engine_class_sysfs.o \
         xe_hw_engine_group.o \
+       xe_hw_error.o \
         xe_hw_fence.o \
         xe_irq.o \
         xe_lrc.o \
diff --git a/drivers/gpu/drm/xe/regs/xe_hw_error_regs.h
b/drivers/gpu/drm/xe/regs/xe_hw_error_regs.h
new file mode 100644
index 000000000000..ed9b81fb28a0
--- /dev/null
+++ b/drivers/gpu/drm/xe/regs/xe_hw_error_regs.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef _XE_HW_ERROR_REGS_H_
+#define _XE_HW_ERROR_REGS_H_
+
+#define DEV_ERR_STAT_NONFATAL                  0x100178
+#define DEV_ERR_STAT_CORRECTABLE               0x10017c
+#define
DEV_ERR_STAT_REG(x)                    XE_REG(_PICK_EVEN((x), \
+
DEV_ERR_STAT_CORRECTABLE, \
+
DEV_ERR_STAT_NONFATAL))
+
+#endif
diff --git a/drivers/gpu/drm/xe/regs/xe_irq_regs.h
b/drivers/gpu/drm/xe/regs/xe_irq_regs.h
index 13635e4331d4..7c2a3a140142 100644
--- a/drivers/gpu/drm/xe/regs/xe_irq_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_irq_regs.h
@@ -18,6 +18,7 @@
  #define GFX_MSTR_IRQ                           XE_REG(0x190010,
XE_REG_OPTION_VF)
  #define   MASTER_IRQ                           REG_BIT(31)
  #define   GU_MISC_IRQ                          REG_BIT(29)
+#define   ERROR_IRQ(x)                         REG_BIT(26 + (x))
  #define   DISPLAY_IRQ                          REG_BIT(16)
  #define   I2C_IRQ                              REG_BIT(12)
  #define   GT_DW_IRQ(x)                         REG_BIT(x)
diff --git a/drivers/gpu/drm/xe/xe_hw_error.c
b/drivers/gpu/drm/xe/xe_hw_error.c
new file mode 100644
index 000000000000..0b09f9950cb9
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_hw_error.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include "regs/xe_hw_error_regs.h"
+#include "regs/xe_irq_regs.h"
+
+#include "xe_device.h"
+#include "xe_hw_error.h"
+#include "xe_mmio.h"
+
+/* Error categories reported by hardware */
+enum hardware_error {
+       HARDWARE_ERROR_CORRECTABLE = 0,
+       HARDWARE_ERROR_NONFATAL = 1,
+       HARDWARE_ERROR_FATAL = 2,
+       HARDWARE_ERROR_MAX,
+};
+
+static const char *hw_error_to_str(const enum hardware_error hw_err)
+{
+       switch (hw_err) {
+       case HARDWARE_ERROR_CORRECTABLE:
+               return "CORRECTABLE";
+       case HARDWARE_ERROR_NONFATAL:
+               return "NONFATAL";
+       case HARDWARE_ERROR_FATAL:
+               return "FATAL";
+       default:
+               return "UNKNOWN";
+       }
+}
+
+static void hw_error_source_handler(struct xe_tile *tile, const enum
hardware_error hw_err)
+{
+       const char *hw_err_str = hw_error_to_str(hw_err);
+       struct xe_device *xe = tile_to_xe(tile);
+       unsigned long flags;
+       u32 err_src;
+
+       spin_lock_irqsave(&xe->irq.lock, flags);
+       err_src = xe_mmio_read32(&tile->mmio,
DEV_ERR_STAT_REG(hw_err));
+       if (!err_src) {
+               drm_err_ratelimited(&xe->drm, HW_ERR "Tile%d reported
DEV_ERR_STAT_%s blank!\n",
+                                   tile->id, hw_err_str);

This message is essentially the same as the one below, just with
"blank" instead of "0x0". And writing back a 0 IMO is inconsequential
since this already is some kind of hardware bug (bad interrupt, MMIO
write error, etc) if we get to this point.

May need to check if we really need error logs or debug should be sufficient. BAT shows errors on probe on DG2

https://intel-gfx-ci.01.org/tree/intel-xe/xe-pw-149756v5/bat-dg2-oem2/igt@xe_module_l...@load.html#dmesg-warnings262

The previous series had a skip for DG2 https://patchwork.freedesktop.org/patch/563668/?series=125373&rev=1 but the review comments don't provide more data.

Will check why there is a failure. We might not need error logs for a
correctable error but need to confirm for Non-fatal.

Thanks
Riana


Can we save a few lines and get rid of this if check? So the function
just becomes:

spin_lock()
read_mmio()
print_results()
write_mmio()
spin_unlock()

Without any goto or extra check.

+               goto unlock;
+       }
+
+       drm_err_ratelimited(&xe->drm, HW_ERR "Tile%d reported %s
error 0x%x\n",
+                           tile->id, hw_err_str, err_src);
+
+       xe_mmio_write32(&tile->mmio, DEV_ERR_STAT_REG(hw_err),
err_src);
+
+unlock:
+       spin_unlock_irqrestore(&xe->irq.lock, flags);
+}
+
+/**
+ * xe_hw_error_irq_handler - irq handling for hw errors
+ * @tile: tile instance
+ * @master_ctl: value read from master interrupt register
+ *
+ * Xe platforms add three error bits to the master interrupt
register to support error handling.
+ * These three bits are used to convey the class of error FATAL,
NONFATAL, or CORRECTABLE.
+ * To process the interrupt, determine the source of error by
reading the Device Error Source
+ * Register that corresponds to the class of error being serviced.
+ */
+void xe_hw_error_irq_handler(struct xe_tile *tile, const u32
master_ctl)
+{
+       enum hardware_error hw_err;
+
+       for (hw_err = 0; hw_err < HARDWARE_ERROR_MAX; hw_err++)
+               if (master_ctl & ERROR_IRQ(hw_err))
+                       hw_error_source_handler(tile, hw_err);
+}
+
+/*
+ * Process hardware errors during boot
+ */
+static void process_hw_errors(struct xe_device *xe)
+{
+       struct xe_tile *tile;
+       u32 master_ctl;
+       u8 id;
+
+       for_each_tile(tile, xe, id) {
+               master_ctl = xe_mmio_read32(&tile->mmio,
GFX_MSTR_IRQ);
+               xe_hw_error_irq_handler(tile, master_ctl);
+               xe_mmio_write32(&tile->mmio, GFX_MSTR_IRQ,
master_ctl);
+       }
+}
+
+/**
+ * xe_hw_error_init - Initialize hw errors
+ * @xe: xe device instance
+ *
+ * Initialize and process hw errors
+ */
+void xe_hw_error_init(struct xe_device *xe)
+{
+       if (IS_SRIOV_VF(xe))
+               return;
+

Maybe a comment here as to why we are doing this on init? Something
like:
/* Check for errors that occurred during boot prior to driver load */

Thanks,
Stuart

+       process_hw_errors(xe);
+}
diff --git a/drivers/gpu/drm/xe/xe_hw_error.h
b/drivers/gpu/drm/xe/xe_hw_error.h
new file mode 100644
index 000000000000..d86e28c5180c
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_hw_error.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+#ifndef XE_HW_ERROR_H_
+#define XE_HW_ERROR_H_
+
+#include <linux/types.h>
+
+struct xe_tile;
+struct xe_device;
+
+void xe_hw_error_irq_handler(struct xe_tile *tile, const u32
master_ctl);
+void xe_hw_error_init(struct xe_device *xe);
+#endif
diff --git a/drivers/gpu/drm/xe/xe_irq.c
b/drivers/gpu/drm/xe/xe_irq.c
index 5df5b8c2a3e4..870edaf69388 100644
--- a/drivers/gpu/drm/xe/xe_irq.c
+++ b/drivers/gpu/drm/xe/xe_irq.c
@@ -18,6 +18,7 @@
  #include "xe_gt.h"
  #include "xe_guc.h"
  #include "xe_hw_engine.h"
+#include "xe_hw_error.h"
  #include "xe_i2c.h"
  #include "xe_memirq.h"
  #include "xe_mmio.h"
@@ -468,6 +469,7 @@ static irqreturn_t dg1_irq_handler(int irq, void
*arg)
                 xe_mmio_write32(mmio, GFX_MSTR_IRQ, master_ctl);
                gt_irq_handler(tile, master_ctl, intr_dw, identity);
+               xe_hw_error_irq_handler(tile, master_ctl);
                /*
                  * Display interrupts (including display backlight
operations
@@ -756,6 +758,8 @@ int xe_irq_install(struct xe_device *xe)
         int nvec = 1;
         int err;
+       xe_hw_error_init(xe);
+
         xe_irq_reset(xe);
        if (xe_device_has_msix(xe)) {


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