[PATCH 10/29] drm/amd/display: enable hostvm based on roimmu active for dcn2.1

[Bhawanpreet Lakha]

From: Dmytro Laktyushkin <Dmytro.Laktyushkin at amd.com>

Enabling hostvm when ROIMMU is not active seems to break GPUVM.
This fixes the issue by not enabling hostvm if ROIMMU is not
activated.

Signed-off-by: Dmytro Laktyushkin <Dmytro.Laktyushkin at amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha at amd.com>
---
 .../drm/amd/display/dc/dcn21/dcn21_hubbub.c   | 40 ++++++++++++-------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c
index 8e7e79f44272..bd247e5e753e 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn21/dcn21_hubbub.c
@@ -22,6 +22,7 @@
  * Authors: AMD
  *
  */
+#include <linux/delay.h>
 #include "dm_services.h"
 #include "dcn20/dcn20_hubbub.h"
 #include "dcn21_hubbub.h"
@@ -71,30 +72,39 @@ static uint32_t convert_and_clamp(
 void dcn21_dchvm_init(struct hubbub *hubbub)
 {
 	struct dcn20_hubbub *hubbub1 = TO_DCN20_HUBBUB(hubbub);
+	uint32_t riommu_active;
+	int i;
 
 	//Init DCHVM block
 	REG_UPDATE(DCHVM_CTRL0, HOSTVM_INIT_REQ, 1);
 
 	//Poll until RIOMMU_ACTIVE = 1
-	//TODO: Figure out interval us and retry count
-	REG_WAIT(DCHVM_RIOMMU_STAT0, RIOMMU_ACTIVE, 1, 5, 100);
+	for (i = 0; i < 100; i++) {
+		REG_GET(DCHVM_RIOMMU_STAT0, RIOMMU_ACTIVE, &riommu_active);
 
-	//Reflect the power status of DCHUBBUB
-	REG_UPDATE(DCHVM_RIOMMU_CTRL0, HOSTVM_POWERSTATUS, 1);
+		if (riommu_active)
+			break;
+		else
+			udelay(5);
+	}
+
+	if (riommu_active) {
+		//Reflect the power status of DCHUBBUB
+		REG_UPDATE(DCHVM_RIOMMU_CTRL0, HOSTVM_POWERSTATUS, 1);
 
-	//Start rIOMMU prefetching
-	REG_UPDATE(DCHVM_RIOMMU_CTRL0, HOSTVM_PREFETCH_REQ, 1);
+		//Start rIOMMU prefetching
+		REG_UPDATE(DCHVM_RIOMMU_CTRL0, HOSTVM_PREFETCH_REQ, 1);
 
-	// Enable dynamic clock gating
-	REG_UPDATE_4(DCHVM_CLK_CTRL,
-					HVM_DISPCLK_R_GATE_DIS, 0,
-					HVM_DISPCLK_G_GATE_DIS, 0,
-					HVM_DCFCLK_R_GATE_DIS, 0,
-					HVM_DCFCLK_G_GATE_DIS, 0);
+		// Enable dynamic clock gating
+		REG_UPDATE_4(DCHVM_CLK_CTRL,
+						HVM_DISPCLK_R_GATE_DIS, 0,
+						HVM_DISPCLK_G_GATE_DIS, 0,
+						HVM_DCFCLK_R_GATE_DIS, 0,
+						HVM_DCFCLK_G_GATE_DIS, 0);
 
-	//Poll until HOSTVM_PREFETCH_DONE = 1
-	//TODO: Figure out interval us and retry count
-	REG_WAIT(DCHVM_RIOMMU_STAT0, HOSTVM_PREFETCH_DONE, 1, 5, 100);
+		//Poll until HOSTVM_PREFETCH_DONE = 1
+		REG_WAIT(DCHVM_RIOMMU_STAT0, HOSTVM_PREFETCH_DONE, 1, 5, 100);
+	}
 }
 
 int hubbub21_init_dchub(struct hubbub *hubbub,
-- 
2.17.1