drm/i915: Prepare for larger CSB status FIFO size

Make csb entry count variable in preparation for larger
CSB status FIFO size found on gen11+ hardware.

v2: adapt to hwsp access only (Chris)
    non continuous mmio (Daniele)
v3: entries (Chris), fix macro for checkpatch
v4: num_entries (Chris)
v5: consistency on num_entries

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190405204657.12887-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -1405,40 +1405,33 @@ static void intel_engine_print_registers(const struct intel_engine_cs *engine,
 	if (HAS_EXECLISTS(dev_priv)) {
 		const u32 *hws =
 			&engine->status_page.addr[I915_HWS_CSB_BUF0_INDEX];
+		const u8 num_entries = execlists->csb_size;
 		unsigned int idx;
 		u8 read, write;
 
-		drm_printf(m, "\tExeclist status: 0x%08x %08x\n",
+		drm_printf(m, "\tExeclist status: 0x%08x %08x, entries %u\n",
 			   ENGINE_READ(engine, RING_EXECLIST_STATUS_LO),
-			   ENGINE_READ(engine, RING_EXECLIST_STATUS_HI));
+			   ENGINE_READ(engine, RING_EXECLIST_STATUS_HI),
+			   num_entries);
 
 		read = execlists->csb_head;
 		write = READ_ONCE(*execlists->csb_write);
 
-		drm_printf(m, "\tExeclist CSB read %d, write %d [mmio:%d], tasklet queued? %s (%s)\n",
+		drm_printf(m, "\tExeclist CSB read %d, write %d, tasklet queued? %s (%s)\n",
 			   read, write,
-			   GEN8_CSB_WRITE_PTR(ENGINE_READ(engine, RING_CONTEXT_STATUS_PTR)),
 			   yesno(test_bit(TASKLET_STATE_SCHED,
 					  &engine->execlists.tasklet.state)),
 			   enableddisabled(!atomic_read(&engine->execlists.tasklet.count)));
-		if (read >= GEN8_CSB_ENTRIES)
+		if (read >= num_entries)
 			read = 0;
-		if (write >= GEN8_CSB_ENTRIES)
+		if (write >= num_entries)
 			write = 0;
 		if (read > write)
-			write += GEN8_CSB_ENTRIES;
+			write += num_entries;
 		while (read < write) {
-			idx = ++read % GEN8_CSB_ENTRIES;
-			drm_printf(m, "\tExeclist CSB[%d]: 0x%08x [mmio:0x%08x], context: %d [mmio:%d]\n",
-				   idx,
-				   hws[idx * 2],
-				   ENGINE_READ_IDX(engine,
-						   RING_CONTEXT_STATUS_BUF_LO,
-						   idx),
-				   hws[idx * 2 + 1],
-				   ENGINE_READ_IDX(engine,
-						   RING_CONTEXT_STATUS_BUF_HI,
-						   idx));
+			idx = ++read % num_entries;
+			drm_printf(m, "\tExeclist CSB[%d]: 0x%08x, context: %d\n",
+				   idx, hws[idx * 2], hws[idx * 2 + 1]);
 		}
 
 		rcu_read_lock();

drivers/gpu/drm/i915/intel_engine_types.h

@@ -246,6 +246,11 @@ struct intel_engine_execlists {
 	 */
 	u32 preempt_complete_status;
 
+	/**
+	 * @csb_size: context status buffer FIFO size
+	 */
+	u8 csb_size;
+
 	/**
 	 * @csb_head: context status buffer head
 	 */

drivers/gpu/drm/i915/intel_lrc.c

@@ -895,7 +895,7 @@ invalidate_csb_entries(const u32 *first, const u32 *last)
 
 static void reset_csb_pointers(struct intel_engine_execlists *execlists)
 {
-	const unsigned int reset_value = GEN8_CSB_ENTRIES - 1;
+	const unsigned int reset_value = execlists->csb_size - 1;
 
 	/*
 	 * After a reset, the HW starts writing into CSB entry [0]. We
@@ -994,6 +994,7 @@ static void process_csb(struct intel_engine_cs *engine)
 	struct intel_engine_execlists * const execlists = &engine->execlists;
 	struct execlist_port *port = execlists->port;
 	const u32 * const buf = execlists->csb_status;
+	const u8 num_entries = execlists->csb_size;
 	u8 head, tail;
 
 	lockdep_assert_held(&engine->timeline.lock);
@@ -1029,7 +1030,7 @@ static void process_csb(struct intel_engine_cs *engine)
 		unsigned int status;
 		unsigned int count;
 
-		if (++head == GEN8_CSB_ENTRIES)
+		if (++head == num_entries)
 			head = 0;
 
 		/*
@@ -2476,6 +2477,8 @@ static int logical_ring_init(struct intel_engine_cs *engine)
 	execlists->csb_write =
 		&engine->status_page.addr[intel_hws_csb_write_index(i915)];
 
+	execlists->csb_size = GEN8_CSB_ENTRIES;
+
 	reset_csb_pointers(execlists);
 
 	return 0;

drivers/gpu/drm/i915/intel_lrc.h

@@ -36,12 +36,10 @@
 #define	  CTX_CTRL_ENGINE_CTX_RESTORE_INHIBIT	(1 << 0)
 #define   CTX_CTRL_RS_CTX_ENABLE		(1 << 1)
 #define	  CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT	(1 << 2)
-#define RING_CONTEXT_STATUS_BUF_BASE(base)	_MMIO((base) + 0x370)
-#define RING_CONTEXT_STATUS_BUF_LO(base, i)	_MMIO((base) + 0x370 + (i) * 8)
-#define RING_CONTEXT_STATUS_BUF_HI(base, i)	_MMIO((base) + 0x370 + (i) * 8 + 4)
 #define RING_CONTEXT_STATUS_PTR(base)		_MMIO((base) + 0x3a0)
 #define RING_EXECLIST_SQ_CONTENTS(base)		_MMIO((base) + 0x510)
 #define RING_EXECLIST_CONTROL(base)		_MMIO((base) + 0x550)
+
 #define	  EL_CTRL_LOAD				(1 << 0)
 
 /* The docs specify that the write pointer wraps around after 5h, "After status
@@ -55,10 +53,11 @@
 #define GEN8_CSB_PTR_MASK 0x7
 #define GEN8_CSB_READ_PTR_MASK (GEN8_CSB_PTR_MASK << 8)
 #define GEN8_CSB_WRITE_PTR_MASK (GEN8_CSB_PTR_MASK << 0)
-#define GEN8_CSB_WRITE_PTR(csb_status) \
-	(((csb_status) & GEN8_CSB_WRITE_PTR_MASK) >> 0)
-#define GEN8_CSB_READ_PTR(csb_status) \
-	(((csb_status) & GEN8_CSB_READ_PTR_MASK) >> 8)
+
+#define GEN11_CSB_ENTRIES 12
+#define GEN11_CSB_PTR_MASK 0xf
+#define GEN11_CSB_READ_PTR_MASK (GEN11_CSB_PTR_MASK << 8)
+#define GEN11_CSB_WRITE_PTR_MASK (GEN11_CSB_PTR_MASK << 0)
 
 enum {
 	INTEL_CONTEXT_SCHEDULE_IN = 0,