drm/xe/oa: Enable Xe2+ overrun mode

Enable Xe2+ overrun mode. For Xe2+, when overrun mode is enabled, there are
no partial reports at the end of buffer, making the OA buffer effectively a
non-power-of-2 size circular buffer whose size, circ_size, is a multiple of
the report size.

v2: Fix implementation of xe_oa_circ_diff/xe_oa_circ_incr (Umesh)

Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240618014609.3233427-18-ashutosh.dixit@intel.com

diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
index 2d398b7231c1c9874e1d636d52dffbbc58fc3746..34206e0b6a08ed914c60123090391203f35955b6 100644 (file)
--- a/drivers/gpu/drm/xe/xe_oa.c
+++ b/drivers/gpu/drm/xe/xe_oa.c
@@ -114,7 +114,14 @@ static const struct xe_oa_format oa_formats[] = {
 
 static u32 xe_oa_circ_diff(struct xe_oa_stream *stream, u32 tail, u32 head)
 {
-       return (tail - head) & (XE_OA_BUFFER_SIZE - 1);
+       return tail >= head ? tail - head :
+               tail + stream->oa_buffer.circ_size - head;
+}
+
+static u32 xe_oa_circ_incr(struct xe_oa_stream *stream, u32 ptr, u32 n)
+{
+       return ptr + n >= stream->oa_buffer.circ_size ?
+               ptr + n - stream->oa_buffer.circ_size : ptr + n;
 }
 
 static void xe_oa_config_release(struct kref *ref)
@@ -288,7 +295,7 @@ static int xe_oa_append_report(struct xe_oa_stream *stream, char __user *buf,
 
        buf += *offset;
 
-       oa_buf_end = stream->oa_buffer.vaddr + XE_OA_BUFFER_SIZE;
+       oa_buf_end = stream->oa_buffer.vaddr + stream->oa_buffer.circ_size;
        report_size_partial = oa_buf_end - report;
 
        if (report_size_partial < report_size) {
@@ -314,7 +321,6 @@ static int xe_oa_append_reports(struct xe_oa_stream *stream, char __user *buf,
        int report_size = stream->oa_buffer.format->size;
        u8 *oa_buf_base = stream->oa_buffer.vaddr;
        u32 gtt_offset = xe_bo_ggtt_addr(stream->oa_buffer.bo);
-       u32 mask = (XE_OA_BUFFER_SIZE - 1);
        size_t start_offset = *offset;
        unsigned long flags;
        u32 head, tail;
@@ -325,21 +331,23 @@ static int xe_oa_append_reports(struct xe_oa_stream *stream, char __user *buf,
        tail = stream->oa_buffer.tail;
        spin_unlock_irqrestore(&stream->oa_buffer.ptr_lock, flags);
 
-       xe_assert(stream->oa->xe, head < XE_OA_BUFFER_SIZE && tail < XE_OA_BUFFER_SIZE);
+       xe_assert(stream->oa->xe,
+                 head < stream->oa_buffer.circ_size && tail < stream->oa_buffer.circ_size);
 
-       for (; xe_oa_circ_diff(stream, tail, head); head = (head + report_size) & mask) {
+       for (; xe_oa_circ_diff(stream, tail, head);
+            head = xe_oa_circ_incr(stream, head, report_size)) {
                u8 *report = oa_buf_base + head;
 
                ret = xe_oa_append_report(stream, buf, count, offset, report);
                if (ret)
                        break;
 
-               if (is_power_of_2(report_size)) {
+               if (!(stream->oa_buffer.circ_size % report_size)) {
                        /* Clear out report id and timestamp to detect unlanded reports */
                        oa_report_id_clear(stream, (void *)report);
                        oa_timestamp_clear(stream, (void *)report);
                } else {
-                       u8 *oa_buf_end = stream->oa_buffer.vaddr + XE_OA_BUFFER_SIZE;
+                       u8 *oa_buf_end = stream->oa_buffer.vaddr + stream->oa_buffer.circ_size;
                        u32 part = oa_buf_end - report;
 
                        /* Zero out the entire report */
@@ -377,7 +385,6 @@ static void xe_oa_init_oa_buffer(struct xe_oa_stream *stream)
        xe_mmio_write32(stream->gt, __oa_regs(stream)->oa_head_ptr,
                        gtt_offset & OAG_OAHEADPTR_MASK);
        stream->oa_buffer.head = 0;
-
        /*
         * PRM says: "This MMIO must be set before the OATAILPTR register and after the
         * OAHEADPTR register. This is to enable proper functionality of the overflow bit".
@@ -1300,6 +1307,18 @@ static int xe_oa_stream_init(struct xe_oa_stream *stream,
        stream->periodic = param->period_exponent > 0;
        stream->period_exponent = param->period_exponent;
 
+       /*
+        * For Xe2+, when overrun mode is enabled, there are no partial reports at the end
+        * of buffer, making the OA buffer effectively a non-power-of-2 size circular
+        * buffer whose size, circ_size, is a multiple of the report size
+        */
+       if (GRAPHICS_VER(stream->oa->xe) >= 20 &&
+           stream->hwe->oa_unit->type == DRM_XE_OA_UNIT_TYPE_OAG && stream->sample)
+               stream->oa_buffer.circ_size =
+                       XE_OA_BUFFER_SIZE - XE_OA_BUFFER_SIZE % stream->oa_buffer.format->size;
+       else
+               stream->oa_buffer.circ_size = XE_OA_BUFFER_SIZE;
+
        if (stream->exec_q && engine_supports_mi_query(stream->hwe)) {
                /* If we don't find the context offset, just return error */
                ret = xe_oa_set_ctx_ctrl_offset(stream);

diff --git a/drivers/gpu/drm/xe/xe_oa_types.h b/drivers/gpu/drm/xe/xe_oa_types.h
index 0981f0e57676281e7e7d9fcbbf3e16b74b38d893..706d45577daec04952c6b201fafc3313a58067fd 100644 (file)
--- a/drivers/gpu/drm/xe/xe_oa_types.h
+++ b/drivers/gpu/drm/xe/xe_oa_types.h
@@ -170,6 +170,9 @@ struct xe_oa_buffer {
 
        /** @tail: The last verified cached tail where HW has completed writing */
        u32 tail;
+
+       /** @circ_size: The effective circular buffer size, for Xe2+ */
+       u32 circ_size;
 };
 
 /**