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Date: Mon, 11 Dec 2017 02:19:43 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Thierry Reding <thierry.reding@...il.com>
Cc: linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/2] drm/tegra: dc: Link DC1 to DC0 on Tegra20
HW reset isn't actually broken on Tegra20, but there is a dependency on
first display controller to be taken out of reset for the second to be
enabled successfully.
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
drivers/gpu/drm/tegra/dc.c | 77 +++++++++++++++++++++++++++++-----------------
drivers/gpu/drm/tegra/dc.h | 4 ++-
2 files changed, 51 insertions(+), 30 deletions(-)
diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index fc70351b9017..6139d3e9cedf 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -24,6 +24,8 @@
#include <drm/drm_atomic_helper.h>
#include <drm/drm_plane_helper.h>
+static struct tegra_dc *dc0;
+
struct tegra_plane {
struct drm_plane base;
unsigned int index;
@@ -1863,7 +1865,7 @@ static const struct tegra_dc_soc_info tegra20_dc_soc_info = {
.supports_block_linear = false,
.pitch_align = 8,
.has_powergate = false,
- .broken_reset = true,
+ .coupled_pm = true,
};
static const struct tegra_dc_soc_info tegra30_dc_soc_info = {
@@ -1873,7 +1875,7 @@ static const struct tegra_dc_soc_info tegra30_dc_soc_info = {
.supports_block_linear = false,
.pitch_align = 8,
.has_powergate = false,
- .broken_reset = false,
+ .coupled_pm = false,
};
static const struct tegra_dc_soc_info tegra114_dc_soc_info = {
@@ -1883,7 +1885,7 @@ static const struct tegra_dc_soc_info tegra114_dc_soc_info = {
.supports_block_linear = false,
.pitch_align = 64,
.has_powergate = true,
- .broken_reset = false,
+ .coupled_pm = false,
};
static const struct tegra_dc_soc_info tegra124_dc_soc_info = {
@@ -1893,7 +1895,7 @@ static const struct tegra_dc_soc_info tegra124_dc_soc_info = {
.supports_block_linear = true,
.pitch_align = 64,
.has_powergate = true,
- .broken_reset = false,
+ .coupled_pm = false,
};
static const struct tegra_dc_soc_info tegra210_dc_soc_info = {
@@ -1903,7 +1905,7 @@ static const struct tegra_dc_soc_info tegra210_dc_soc_info = {
.supports_block_linear = true,
.pitch_align = 64,
.has_powergate = true,
- .broken_reset = false,
+ .coupled_pm = false,
};
static const struct of_device_id tegra_dc_of_match[] = {
@@ -1985,6 +1987,24 @@ static int tegra_dc_probe(struct platform_device *pdev)
if (err < 0)
return err;
+ /*
+ * On Tegra20 DC1 requires DC0 to be taken out of reset in order to
+ * be enabled, otherwise CPU hangs on writing to CMD_DISPLAY_COMMAND /
+ * POWER_CONTROL registers during CRTC enabling.
+ */
+ if (dc->pipe == 1 && dc->soc->coupled_pm) {
+ int link_flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE;
+
+ if (!dc0)
+ return -EPROBE_DEFER;
+
+ dc->link = device_link_add(&pdev->dev, dc0->dev, link_flags);
+ if (!dc->link) {
+ dev_err(&pdev->dev, "failed to link to DC0\n");
+ return -EINVAL;
+ }
+ }
+
dc->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(dc->clk)) {
dev_err(&pdev->dev, "failed to get clock\n");
@@ -1998,21 +2018,19 @@ static int tegra_dc_probe(struct platform_device *pdev)
}
/* assert reset and disable clock */
- if (!dc->soc->broken_reset) {
- err = clk_prepare_enable(dc->clk);
- if (err < 0)
- return err;
+ err = clk_prepare_enable(dc->clk);
+ if (err < 0)
+ return err;
- usleep_range(2000, 4000);
+ usleep_range(2000, 4000);
- err = reset_control_assert(dc->rst);
- if (err < 0)
- return err;
+ err = reset_control_assert(dc->rst);
+ if (err < 0)
+ return err;
- usleep_range(2000, 4000);
+ usleep_range(2000, 4000);
- clk_disable_unprepare(dc->clk);
- }
+ clk_disable_unprepare(dc->clk);
if (dc->soc->has_powergate) {
if (dc->pipe == 0)
@@ -2054,6 +2072,9 @@ static int tegra_dc_probe(struct platform_device *pdev)
return err;
}
+ if (dc->pipe == 0)
+ dc0 = dc;
+
return 0;
}
@@ -2077,6 +2098,9 @@ static int tegra_dc_remove(struct platform_device *pdev)
pm_runtime_disable(&pdev->dev);
+ if (dc == dc0)
+ dc0 = NULL;
+
return 0;
}
@@ -2086,12 +2110,10 @@ static int tegra_dc_suspend(struct device *dev)
struct tegra_dc *dc = dev_get_drvdata(dev);
int err;
- if (!dc->soc->broken_reset) {
- err = reset_control_assert(dc->rst);
- if (err < 0) {
- dev_err(dev, "failed to assert reset: %d\n", err);
- return err;
- }
+ err = reset_control_assert(dc->rst);
+ if (err < 0) {
+ dev_err(dev, "failed to assert reset: %d\n", err);
+ return err;
}
if (dc->soc->has_powergate)
@@ -2121,13 +2143,10 @@ static int tegra_dc_resume(struct device *dev)
return err;
}
- if (!dc->soc->broken_reset) {
- err = reset_control_deassert(dc->rst);
- if (err < 0) {
- dev_err(dev,
- "failed to deassert reset: %d\n", err);
- return err;
- }
+ err = reset_control_deassert(dc->rst);
+ if (err < 0) {
+ dev_err(dev, "failed to deassert reset: %d\n", err);
+ return err;
}
}
diff --git a/drivers/gpu/drm/tegra/dc.h b/drivers/gpu/drm/tegra/dc.h
index cb100b6e3282..1d772ed78301 100644
--- a/drivers/gpu/drm/tegra/dc.h
+++ b/drivers/gpu/drm/tegra/dc.h
@@ -32,7 +32,7 @@ struct tegra_dc_soc_info {
bool supports_block_linear;
unsigned int pitch_align;
bool has_powergate;
- bool broken_reset;
+ bool coupled_pm;
};
struct tegra_dc {
@@ -65,6 +65,8 @@ struct tegra_dc {
const struct tegra_dc_soc_info *soc;
struct iommu_domain *domain;
+
+ struct device_link *link;
};
static inline struct tegra_dc *
--
2.15.1
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