diff options
Diffstat (limited to 'drivers/clk/qcom/gpucc-sc7180.c')
| -rw-r--r-- | drivers/clk/qcom/gpucc-sc7180.c | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/drivers/clk/qcom/gpucc-sc7180.c b/drivers/clk/qcom/gpucc-sc7180.c index a96c0b945de2..7b656b6aeced 100644 --- a/drivers/clk/qcom/gpucc-sc7180.c +++ b/drivers/clk/qcom/gpucc-sc7180.c @@ -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[] = { |