On Thu, May 06, 2021 at 12:13:32PM -0700, Matthew Brost wrote:
> From: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
>
> 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@xxxxxxxxx>
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 67 ++++++++++++++++-------
> drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h | 3 +
> 2 files changed, 50 insertions(+), 20 deletions(-)
>
> 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 cb58fa7f970c..d630ec32decf 100644
> --- 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(unsigned long data);
> 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_init(&ct->receive_tasklet, ct_receive_tasklet_func, (unsigned long)ct);
This function is deprecated. tasklet_setup should be used.
I can fix this up when I post the CTB patches.
> }
>
> 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));
> }
> @@ -629,7 +632,7 @@ 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",
> @@ -665,10 +668,10 @@ 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)) {
> @@ -688,7 +691,7 @@ 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",
> @@ -707,7 +710,7 @@ 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);
> @@ -821,31 +824,55 @@ 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(unsigned long data)
> +{
As mentioned above tasklet_init is deprecated. The callback now accepts
the tasklet structure and ct can be looked up via container_of macro.
Everything else looks good.
With that and changing to the new tasklet API:
Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> + struct intel_guc_ct *ct = (struct intel_guc_ct *)data;
> +
> + 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 bc52dc479a14..cb222f202301 100644
> --- 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 */
>
> --
> 2.28.0
>
