[PATCH 2/5] genpd/gdsc: inherit display powerdomain from bootloader

[Rob Clark <robdclark@xxxxxxxxx>]

From: Rob Clark <robdclark@xxxxxxxxxxxx>

Mark power domains that may be enabled by bootloader, and which should
not be disabled until a driver takes them over.

This keeps efifb alive until the real driver can be probed.  In a distro
kernel, the driver will most likely built as a module, and not probed
until we get to userspace (after late_initcall)

Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
 drivers/base/power/domain.c      | 10 ++++++++++
 drivers/clk/qcom/dispcc-sdm845.c |  2 +-
 drivers/clk/qcom/gdsc.c          |  5 +++++
 drivers/clk/qcom/gdsc.h          |  1 +
 include/linux/pm_domain.h        |  4 ++++
 5 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 33c30c1e6a30..513a8655fbd7 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -537,6 +537,16 @@ static int genpd_power_off(struct generic_pm_domain *genpd, bool one_dev_on,
 			not_suspended++;
 	}
 
+	/*
+	 * If the power domain is enabled by the bootloader (for example
+	 * display enabled by bootloader), but no devices attached yet
+	 * (perhaps because driver built as kernel module), then do not
+	 * suspend.
+	 */
+	if ((genpd->flags & GENPD_FLAG_INHERIT_BL) &&
+		list_empty(&genpd->dev_list))
+		not_suspended++;
+
 	if (not_suspended > 1 || (not_suspended == 1 && !one_dev_on))
 		return -EBUSY;
 
diff --git a/drivers/clk/qcom/dispcc-sdm845.c b/drivers/clk/qcom/dispcc-sdm845.c
index 40d7e0ab4340..1d9365ac2315 100644
--- a/drivers/clk/qcom/dispcc-sdm845.c
+++ b/drivers/clk/qcom/dispcc-sdm845.c
@@ -575,7 +575,7 @@ static struct gdsc mdss_gdsc = {
 		.name = "mdss_gdsc",
 	},
 	.pwrsts = PWRSTS_OFF_ON,
-	.flags = HW_CTRL | POLL_CFG_GDSCR,
+	.flags = HW_CTRL | POLL_CFG_GDSCR | INHERIT_BL,
 };
 
 static struct clk_regmap *disp_cc_sdm845_clocks[] = {
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index a250f59708d8..4639fbeb9a7f 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -331,6 +331,11 @@ static int gdsc_init(struct gdsc *sc)
 	if ((sc->flags & VOTABLE) && on)
 		gdsc_enable(&sc->pd);
 
+	if ((sc->flags & INHERIT_BL) && on) {
+		pr_debug("gdsc: %s is enabled from bootloader!\n", sc->pd.name);
+		sc->pd.flags |= GENPD_FLAG_INHERIT_BL;
+	}
+
 	/* If ALWAYS_ON GDSCs are not ON, turn them ON */
 	if (sc->flags & ALWAYS_ON) {
 		if (!on)
diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 64cdc8cf0d4d..c6fe56247399 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -49,6 +49,7 @@ struct gdsc {
 #define AON_RESET	BIT(4)
 #define POLL_CFG_GDSCR	BIT(5)
 #define ALWAYS_ON	BIT(6)
+#define INHERIT_BL	BIT(7)
 	struct reset_controller_dev	*rcdev;
 	unsigned int			*resets;
 	unsigned int			reset_count;
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 91d9bf497071..5e421afcf6f3 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -55,6 +55,9 @@
  *
  * GENPD_FLAG_RPM_ALWAYS_ON:	Instructs genpd to always keep the PM domain
  *				powered on except for system suspend.
+ *
+ * GENPD_FLAG_INHERIT_BL:	The bootloader has already enabled this power
+ * 				domain.
  */
 #define GENPD_FLAG_PM_CLK	 (1U << 0)
 #define GENPD_FLAG_IRQ_SAFE	 (1U << 1)
@@ -62,6 +65,7 @@
 #define GENPD_FLAG_ACTIVE_WAKEUP (1U << 3)
 #define GENPD_FLAG_CPU_DOMAIN	 (1U << 4)
 #define GENPD_FLAG_RPM_ALWAYS_ON (1U << 5)
+#define GENPD_FLAG_INHERIT_BL	 (1U << 6)
 
 enum gpd_status {
 	GPD_STATE_ACTIVE = 0,	/* PM domain is active */
-- 
2.20.1