[PATCH 2/3] drm/xe: Manage MSI-X interrupts allocation

Levi, Ilia ilia.levi at intel.com
Mon Nov 4 14:47:03 UTC 2024


Expose functions to request and free MSI-X interrupts.

The request has two flavors:
- Static MSI-X allocation, for known MSI-X interrupts (e.g. GuC-to-host)
- Dynamic MSI-X allocation, which uses the next available MSI-X interrupt

Signed-off-by: Ilia Levi <ilia.levi at intel.com>
---
 drivers/gpu/drm/xe/xe_device_types.h |  2 +
 drivers/gpu/drm/xe/xe_irq_msix.c     | 90 ++++++++++++++++++++++------
 drivers/gpu/drm/xe/xe_irq_msix.h     |  5 ++
 3 files changed, 80 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 8237bb1474c6..c7a695741feb 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -355,6 +355,8 @@ struct xe_device {
             u16 num_of_interrupts;
             /** @irq.msix.default_msix: Default MSI-X vector */
             u16 default_msix;
+            /** @irq.msix.indexes: used to allocate MSI-X indexes */
+            struct xarray indexes;
         } msix;
     } irq;
 
diff --git a/drivers/gpu/drm/xe/xe_irq_msix.c b/drivers/gpu/drm/xe/xe_irq_msix.c
index dac339ba5ed2..f873bcfe5283 100644
--- a/drivers/gpu/drm/xe/xe_irq_msix.c
+++ b/drivers/gpu/drm/xe/xe_irq_msix.c
@@ -24,6 +24,7 @@ void xe_irq_msix_init(struct xe_device *xe, int nvec)
     xe->irq.msix.enabled = true;
     xe->irq.msix.num_of_interrupts = nvec;
     xe->irq.msix.default_msix = DEFAULT_MSIX;
+    xa_init_flags(&xe->irq.msix.indexes, XA_FLAGS_ALLOC);
 }
 
 static irqreturn_t guc2host_irq_handler(int irq, void *arg)
@@ -66,8 +67,32 @@ static irqreturn_t xe_irq_msix_default_hwe_handler(int irq, void *arg)
     return IRQ_HANDLED;
 }
 
-static int xe_irq_msix_request_irq(struct xe_device *xe, irq_handler_t handler,
-                   const char *name, u16 msix)
+static int xe_irq_msix_alloc_vector(struct xe_device *xe, void *irq_buf,
+                    bool dynamic_msix, u16 *msix)
+{
+    struct xa_limit limit;
+    int ret;
+    u32 id;
+
+    limit = (dynamic_msix) ? XA_LIMIT(NUM_OF_STATIC_MSIX, xe->irq.msix.num_of_interrupts - 1) :
+                 XA_LIMIT(*msix, *msix);
+    ret = xa_alloc(&xe->irq.msix.indexes, &id, irq_buf, limit, GFP_KERNEL);
+    if (ret)
+        return ret;
+
+    if (dynamic_msix)
+        *msix = id;
+
+    return 0;
+}
+
+static void xe_irq_msix_release_vector(struct xe_device *xe, u16 msix)
+{
+    xa_erase(&xe->irq.msix.indexes, msix);
+}
+
+static int xe_irq_msix_request_irq_internal(struct xe_device *xe, irq_handler_t handler,
+                        void *irq_buf, const char *name, u16 msix)
 {
     struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
     int ret, irq;
@@ -76,17 +101,41 @@ static int xe_irq_msix_request_irq(struct xe_device *xe, irq_handler_t handler,
     if (irq < 0)
         return irq;
 
-    ret = request_irq(irq, handler, IRQF_SHARED, name, xe);
+    ret = request_irq(irq, handler, IRQF_SHARED, name, irq_buf);
     if (ret < 0)
         return ret;
 
     return 0;
 }
 
-static void xe_irq_msix_free_irq(struct xe_device *xe, u16 msix)
+int xe_irq_msix_request_irq(struct xe_device *xe, irq_handler_t handler, void *irq_buf,
+                const char *name, bool dynamic_msix, u16 *msix)
+{
+    int ret;
+
+    ret = xe_irq_msix_alloc_vector(xe, irq_buf, dynamic_msix, msix);
+    if (ret)
+        return ret;
+
+    ret = xe_irq_msix_request_irq_internal(xe, handler, irq_buf, name, *msix);
+    if (ret) {
+        drm_err(&xe->drm, "Failed to request IRQ for MSI-X %u\n", *msix);
+        xe_irq_msix_release_vector(xe, *msix);
+        return ret;
+    }
+
+    return 0;
+}
+
+void xe_irq_msix_free_irq(struct xe_device *xe, u16 msix)
 {
     struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
     int irq;
+    void *irq_buf;
+
+    irq_buf = xa_load(&xe->irq.msix.indexes, msix);
+    if (!irq_buf)
+        return;
 
     irq = pci_irq_vector(pdev, msix);
     if (irq < 0) {
@@ -94,24 +143,25 @@ static void xe_irq_msix_free_irq(struct xe_device *xe, u16 msix)
         return;
     }
 
-    free_irq(irq, xe);
+    free_irq(irq, irq_buf);
+    xe_irq_msix_release_vector(xe, msix);
 }
 
 int xe_irq_msix_request(struct xe_device *xe)
 {
     int err;
+    u16 msix;
 
-    err = xe_irq_msix_request_irq(xe, guc2host_irq_handler,
-                      DRIVER_NAME "-guc2host", GUC2HOST_MSIX);
-    if (err) {
-        drm_err(&xe->drm, "Failed to request MSI-X IRQ %d: %d\n", GUC2HOST_MSIX, err);
+    msix = GUC2HOST_MSIX;
+    err = xe_irq_msix_request_irq(xe, guc2host_irq_handler, xe,
+                      DRIVER_NAME "-guc2host", false, &msix);
+    if (err)
         return err;
-    }
 
-    err = xe_irq_msix_request_irq(xe, xe_irq_msix_default_hwe_handler,
-                      DRIVER_NAME "-default-msix", DEFAULT_MSIX);
+    msix = DEFAULT_MSIX;
+    err = xe_irq_msix_request_irq(xe, xe_irq_msix_default_hwe_handler, xe,
+                      DRIVER_NAME "-default-msix", false, &msix);
     if (err) {
-        drm_err(&xe->drm, "Failed to request MSI-X IRQ %d: %d\n", DEFAULT_MSIX, err);
         xe_irq_msix_free_irq(xe, GUC2HOST_MSIX);
         return err;
     }
@@ -121,14 +171,20 @@ int xe_irq_msix_request(struct xe_device *xe)
 
 void xe_irq_msix_free(struct xe_device *xe)
 {
-    xe_irq_msix_free_irq(xe, GUC2HOST_MSIX);
-    xe_irq_msix_free_irq(xe, DEFAULT_MSIX);
+    unsigned long msix;
+    u32 *dummy;
+
+    xa_for_each(&xe->irq.msix.indexes, msix, dummy)
+        xe_irq_msix_free_irq(xe, msix);
+    xa_destroy(&xe->irq.msix.indexes);
 }
 
 void xe_irq_msix_synchronize_irq(struct xe_device *xe)
 {
     struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+    unsigned long msix;
+    u32 *dummy;
 
-    synchronize_irq(pci_irq_vector(pdev, GUC2HOST_MSIX));
-    synchronize_irq(pci_irq_vector(pdev, DEFAULT_MSIX));
+    xa_for_each(&xe->irq.msix.indexes, msix, dummy)
+        synchronize_irq(pci_irq_vector(pdev, msix));
 }
diff --git a/drivers/gpu/drm/xe/xe_irq_msix.h b/drivers/gpu/drm/xe/xe_irq_msix.h
index 9c36d11f05fc..a9c8ce18172e 100644
--- a/drivers/gpu/drm/xe/xe_irq_msix.h
+++ b/drivers/gpu/drm/xe/xe_irq_msix.h
@@ -6,11 +6,16 @@
 #ifndef _XE_IRQ_MSIX_H_
 #define _XE_IRQ_MSIX_H_
 
+#include <linux/interrupt.h>
+
 struct xe_device;
 
 void xe_irq_msix_init(struct xe_device *xe, int nvec);
 void xe_irq_msix_free(struct xe_device *xe);
 int xe_irq_msix_request(struct xe_device *xe);
 void xe_irq_msix_synchronize_irq(struct xe_device *xe);
+int xe_irq_msix_request_irq(struct xe_device *xe, irq_handler_t handler, void *irq_buf,
+                const char *name, bool dynamic_msix, u16 *msix);
+void xe_irq_msix_free_irq(struct xe_device *xe, u16 msix);
 
 #endif
-- 
2.43.2




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