Commit 1a615112 authored by Taniya Das's avatar Taniya Das Committed by Stephen Boyd
Browse files

clk: qcom: gpucc: Add support for GX GDSC for SC7180 



Most of the time the CPU should not be touching the GX domain on the
GPU except for a very special use case when the CPU needs to force the
GX headswitch off. Add the GX domain for that use case.  As part of
this add a dummy enable function for the GX gdsc to simulate success
so that the pm_runtime reference counting is correct.  This matches
what was done in sdm845 in commit 85a3d920 ("clk: qcom: Add a
dummy enable function for GX gdsc").

Signed-off-by: default avatarTaniya Das <tdas@codeaurora.org>
Reviewed-by: default avatarDouglas Anderson <dianders@chromium.org>
Link: https://lkml.kernel.org/r/1581307266-26989-2-git-send-email-tdas@codeaurora.org


Signed-off-by: default avatarStephen Boyd <sboyd@kernel.org>
parent 04ac0ad7

drivers/clk/qcom/gpucc-sc7180.c

+37 −0
Original line number Diff line number Diff line
@@ -170,8 +170,45 @@ static struct gdsc cx_gdsc = { 
	.flags = VOTABLE,

};



/*

 * On SC7180 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.

 */

static int gx_gdsc_enable(struct generic_pm_domain *domain)

{

	/* Do nothing but give genpd the impression that we were successful */

	return 0;

}



static struct gdsc gx_gdsc = {

	.gdscr = 0x100c,

	.clamp_io_ctrl = 0x1508,

	.pd = {

		.name = "gx_gdsc",

		.power_on = gx_gdsc_enable,

	},

	.pwrsts = PWRSTS_OFF_ON,

	.flags = CLAMP_IO,

};



static struct gdsc *gpu_cc_sc7180_gdscs[] = {

	[CX_GDSC] = &cx_gdsc,

	[GX_GDSC] = &gx_gdsc,

};



static struct clk_regmap *gpu_cc_sc7180_clocks[] = {

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