From b386c6b73ac6c2a9a2f1201d055ab65cc19890a2 Mon Sep 17 00:00:00 2001
From: Thierry Reding <treding@nvidia.com>
Date: Tue, 21 Mar 2017 08:54:22 +0100
Subject: [PATCH] gpu: host1x: Support module reset

Newer versions of Tegra come with early boot software that aggressively
puts various modules in reset. Add support to the host1x driver to take
the module out of reset on probe, and assert reset on removal.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/host1x/dev.c | 18 +++++++++++++++++-
 drivers/gpu/host1x/dev.h |  2 ++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 8a0d97243c9c..f05ebb14fa63 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -170,6 +170,13 @@ static int host1x_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	host->rst = devm_reset_control_get(&pdev->dev, "host1x");
+	if (IS_ERR(host->rst)) {
+		err = PTR_ERR(host->clk);
+		dev_err(&pdev->dev, "failed to get reset: %d\n", err);
+		return err;
+	}
+
 	if (iommu_present(&platform_bus_type)) {
 		struct iommu_domain_geometry *geometry;
 		unsigned long order;
@@ -203,10 +210,16 @@ static int host1x_probe(struct platform_device *pdev)
 		goto fail_detach_device;
 	}
 
+	err = reset_control_deassert(host->rst);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to deassert reset: %d\n", err);
+		goto fail_unprepare_disable;
+	}
+
 	err = host1x_syncpt_init(host);
 	if (err) {
 		dev_err(&pdev->dev, "failed to initialize syncpts\n");
-		goto fail_unprepare_disable;
+		goto fail_reset_assert;
 	}
 
 	err = host1x_intr_init(host, syncpt_irq);
@@ -227,6 +240,8 @@ static int host1x_probe(struct platform_device *pdev)
 	host1x_intr_deinit(host);
 fail_deinit_syncpt:
 	host1x_syncpt_deinit(host);
+fail_reset_assert:
+	reset_control_assert(host->rst);
 fail_unprepare_disable:
 	clk_disable_unprepare(host->clk);
 fail_detach_device:
@@ -248,6 +263,7 @@ static int host1x_remove(struct platform_device *pdev)
 	host1x_unregister(host);
 	host1x_intr_deinit(host);
 	host1x_syncpt_deinit(host);
+	reset_control_assert(host->rst);
 	clk_disable_unprepare(host->clk);
 
 	if (host->domain) {
diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index 561c5776cafb..229d08b6a45e 100644
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -21,6 +21,7 @@
 #include <linux/iommu.h>
 #include <linux/iova.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 
 #include "cdma.h"
 #include "channel.h"
@@ -109,6 +110,7 @@ struct host1x {
 	struct host1x_syncpt_base *bases;
 	struct device *dev;
 	struct clk *clk;
+	struct reset_control *rst;
 
 	struct iommu_domain *domain;
 	struct iova_domain iova;