drm/i915/guc: Don't receive all G2H messages in irq handler

In irq handler try to receive just single G2H message, let other
messages to be received from tasklet.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210603051630.2635-18-matthew.brost@intel.com

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
index 1745f89..6e83151 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
@@ -81,6 +81,7 @@ enum { CTB_SEND = 0, CTB_RECV = 1 };
 
 enum { CTB_OWNER_HOST = 0 };
 
+static void ct_receive_tasklet_func(struct tasklet_struct *t);
 static void ct_incoming_request_worker_func(struct work_struct *w);
 
 /**
@@ -95,6 +96,7 @@ void intel_guc_ct_init_early(struct intel_guc_ct *ct)
        INIT_LIST_HEAD(&ct->requests.pending);
        INIT_LIST_HEAD(&ct->requests.incoming);
        INIT_WORK(&ct->requests.worker, ct_incoming_request_worker_func);
+       tasklet_setup(&ct->receive_tasklet, ct_receive_tasklet_func);
 }
 
 static inline const char *guc_ct_buffer_type_to_str(u32 type)
@@ -244,6 +246,7 @@ void intel_guc_ct_fini(struct intel_guc_ct *ct)
 {
        GEM_BUG_ON(ct->enabled);
 
+       tasklet_kill(&ct->receive_tasklet);
        i915_vma_unpin_and_release(&ct->vma, I915_VMA_RELEASE_MAP);
        memset(ct, 0, sizeof(*ct));
 }
@@ -651,7 +654,7 @@ static int ct_read(struct intel_guc_ct *ct, u32 *data)
        CT_DEBUG(ct, "received %*ph\n", 4 * len, data);
 
        desc->head = head * 4;
-       return 0;
+       return available - len;
 
 corrupted:
        CT_ERROR(ct, "Corrupted descriptor addr=%#x head=%u tail=%u size=%u\n",
@@ -687,10 +690,10 @@ static int ct_handle_response(struct intel_guc_ct *ct, const u32 *msg)
        u32 status;
        u32 datalen;
        struct ct_request *req;
+       unsigned long flags;
        bool found = false;
 
        GEM_BUG_ON(!ct_header_is_response(header));
-       GEM_BUG_ON(!in_irq());
 
        /* Response payload shall at least include fence and status */
        if (unlikely(len < 2)) {
@@ -710,7 +713,7 @@ static int ct_handle_response(struct intel_guc_ct *ct, const u32 *msg)
 
        CT_DEBUG(ct, "response fence %u status %#x\n", fence, status);
 
-       spin_lock(&ct->requests.lock);
+       spin_lock_irqsave(&ct->requests.lock, flags);
        list_for_each_entry(req, &ct->requests.pending, link) {
                if (unlikely(fence != req->fence)) {
                        CT_DEBUG(ct, "request %u awaits response\n",
@@ -729,7 +732,7 @@ static int ct_handle_response(struct intel_guc_ct *ct, const u32 *msg)
                found = true;
                break;
        }
-       spin_unlock(&ct->requests.lock);
+       spin_unlock_irqrestore(&ct->requests.lock, flags);
 
        if (!found)
                CT_ERROR(ct, "Unsolicited response %*ph\n", msgsize, msg);
@@ -843,31 +846,55 @@ static int ct_handle_request(struct intel_guc_ct *ct, const u32 *msg)
        return 0;
 }
 
+static int ct_receive(struct intel_guc_ct *ct)
+{
+       u32 msg[GUC_CT_MSG_LEN_MASK + 1]; /* one extra dw for the header */
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&ct->ctbs.recv.lock, flags);
+       ret = ct_read(ct, msg);
+       spin_unlock_irqrestore(&ct->ctbs.recv.lock, flags);
+       if (ret < 0)
+               return ret;
+
+       if (ct_header_is_response(msg[0]))
+               ct_handle_response(ct, msg);
+       else
+               ct_handle_request(ct, msg);
+
+       return ret;
+}
+
+static void ct_try_receive_message(struct intel_guc_ct *ct)
+{
+       int ret;
+
+       if (GEM_WARN_ON(!ct->enabled))
+               return;
+
+       ret = ct_receive(ct);
+       if (ret > 0)
+               tasklet_hi_schedule(&ct->receive_tasklet);
+}
+
+static void ct_receive_tasklet_func(struct tasklet_struct *t)
+{
+       struct intel_guc_ct *ct = from_tasklet(ct, t, receive_tasklet);
+
+       ct_try_receive_message(ct);
+}
+
 /*
  * When we're communicating with the GuC over CT, GuC uses events
  * to notify us about new messages being posted on the RECV buffer.
  */
 void intel_guc_ct_event_handler(struct intel_guc_ct *ct)
 {
-       u32 msg[GUC_CT_MSG_LEN_MASK + 1]; /* one extra dw for the header */
-       unsigned long flags;
-       int err = 0;
-
        if (unlikely(!ct->enabled)) {
                WARN(1, "Unexpected GuC event received while CT disabled!\n");
                return;
        }
 
-       do {
-               spin_lock_irqsave(&ct->ctbs.recv.lock, flags);
-               err = ct_read(ct, msg);
-               spin_unlock_irqrestore(&ct->ctbs.recv.lock, flags);
-               if (err)
-                       break;
-
-               if (ct_header_is_response(msg[0]))
-                       err = ct_handle_response(ct, msg);
-               else
-                       err = ct_handle_request(ct, msg);
-       } while (!err);
+       ct_try_receive_message(ct);
 }

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
index bc52dc4..cb222f2 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h
@@ -6,6 +6,7 @@
 #ifndef _INTEL_GUC_CT_H_
 #define _INTEL_GUC_CT_H_
 
+#include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/workqueue.h>
 
@@ -55,6 +56,8 @@ struct intel_guc_ct {
                struct intel_guc_ct_buffer recv;
        } ctbs;
 
+       struct tasklet_struct receive_tasklet;
+
        struct {
                u32 last_fence; /* last fence used to send request */