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path: root/drivers/clk/qcom/gdsc.c
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Diffstat (limited to 'drivers/clk/qcom/gdsc.c')
-rw-r--r--drivers/clk/qcom/gdsc.c39
1 files changed, 39 insertions, 0 deletions
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index 04944f11659b..bfc4ac02f9ea 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -6,6 +6,7 @@
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
+#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
@@ -29,6 +30,7 @@
/* CFG_GDSCR */
#define GDSC_POWER_UP_COMPLETE BIT(16)
#define GDSC_POWER_DOWN_COMPLETE BIT(15)
+#define GDSC_RETAIN_FF_ENABLE BIT(11)
#define CFG_GDSCR_OFFSET 0x4
/* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
@@ -216,6 +218,14 @@ static inline void gdsc_assert_reset_aon(struct gdsc *sc)
regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
GMEM_RESET_MASK, 0);
}
+
+static void gdsc_retain_ff_on(struct gdsc *sc)
+{
+ u32 mask = GDSC_RETAIN_FF_ENABLE;
+
+ regmap_update_bits(sc->regmap, sc->gdscr, mask, mask);
+}
+
static int gdsc_enable(struct generic_pm_domain *domain)
{
struct gdsc *sc = domain_to_gdsc(domain);
@@ -268,6 +278,9 @@ static int gdsc_enable(struct generic_pm_domain *domain)
udelay(1);
}
+ if (sc->flags & RETAIN_FF_ENABLE)
+ gdsc_retain_ff_on(sc);
+
return 0;
}
@@ -433,3 +446,29 @@ void gdsc_unregister(struct gdsc_desc *desc)
}
of_genpd_del_provider(dev->of_node);
}
+
+/*
+ * On SDM845+ the GPU GX domain is *almost* entirely controlled by the GMU
+ * running in the CX domain so the CPU doesn't need to know anything about the
+ * GX domain EXCEPT....
+ *
+ * Hardware constraints dictate that the GX be powered down before the CX. If
+ * the GMU crashes it could leave the GX on. In order to successfully bring back
+ * the device the CPU needs to disable the GX headswitch. There being no sane
+ * way to reach in and touch that register from deep inside the GPU driver we
+ * need to set up the infrastructure to be able to ensure that the GPU can
+ * ensure that the GX is off during this super special case. We do this by
+ * defining a GX gdsc with a dummy enable function and a "default" disable
+ * function.
+ *
+ * This allows us to attach with genpd_dev_pm_attach_by_name() in the GPU
+ * driver. During power up, nothing will happen from the CPU (and the GMU will
+ * power up normally but during power down this will ensure that the GX domain
+ * is *really* off - this gives us a semi standard way of doing what we need.
+ */
+int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain)
+{
+ /* Do nothing but give genpd the impression that we were successful */
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gdsc_gx_do_nothing_enable);