gpu: nvgpu: API to extract context id

Add new API gr_gk20a_get_ctx_id() to get/extract
context id from GR context

Bug 200156699

Change-Id: If0e8887a9a6b139cd795bf03f5def64fd664d12b
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/927130
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

drivers/gpu/nvgpu/gk20a/gr_gk20a.c

@@ -86,6 +86,31 @@ static int gr_gk20a_init_golden_ctx_image(struct gk20a *g,
 /*elcg init */
 static void gr_gk20a_enable_elcg(struct gk20a *g);
 
+int gr_gk20a_get_ctx_id(struct gk20a *g,
+		struct channel_gk20a *c,
+		u32 *ctx_id)
+{
+	struct channel_ctx_gk20a *ch_ctx = &c->ch_ctx;
+	void *ctx_ptr = NULL;
+
+	/* Channel gr_ctx buffer is gpu cacheable.
+	   Flush and invalidate before cpu update. */
+	g->ops.mm.l2_flush(g, true);
+
+	ctx_ptr = vmap(ch_ctx->gr_ctx->mem.pages,
+			PAGE_ALIGN(ch_ctx->gr_ctx->mem.size) >> PAGE_SHIFT,
+			0, pgprot_writecombine(PAGE_KERNEL));
+	if (!ctx_ptr)
+		return -ENOMEM;
+
+	*ctx_id = gk20a_mem_rd32(ctx_ptr +
+				 ctxsw_prog_main_image_context_id_o(), 0);
+
+	vunmap(ctx_ptr);
+
+	return 0;
+}
+
 void gk20a_fecs_dump_falcon_stats(struct gk20a *g)
 {
 	int i;

drivers/gpu/nvgpu/gk20a/gr_gk20a.h

@@ -562,4 +562,8 @@ int gr_gk20a_ctx_wait_ucode(struct gk20a *g, u32 mailbox_id,
 			    u32 mailbox_ok, u32 opc_fail,
 			    u32 mailbox_fail, bool sleepduringwait);
 
+int gr_gk20a_get_ctx_id(struct gk20a *g,
+		struct channel_gk20a *c,
+		u32 *ctx_id);
+
 #endif /*__GR_GK20A_H__*/

drivers/gpu/nvgpu/gk20a/hw_ctxsw_prog_gk20a.h

@@ -242,4 +242,8 @@ static inline u32 ctxsw_prog_main_image_misc_options_verif_features_disabled_f(v
 {
 	return 0x0;
 }
+static inline u32 ctxsw_prog_main_image_context_id_o(void)
+{
+	return 0x000000f0;
+}
 #endif

drivers/gpu/nvgpu/gm20b/hw_ctxsw_prog_gm20b.h

@@ -270,4 +270,8 @@ static inline u32 ctxsw_prog_main_image_preemption_options_control_cta_enabled_f
 {
 	return 0x1;
 }
+static inline u32 ctxsw_prog_main_image_context_id_o(void)
+{
+	return 0x000000f0;
+}
 #endif