| Message ID | 20181126165416.32519-3-jcrouse@codeaurora.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | clk: qcom: | expand |
On Mon 26 Nov 08:54 PST 2018, Jordan Crouse wrote: > 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 a > dummy enable function for the GX gdsc to simulate success > so that the pm_runtime reference counting is correct. > > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Regards, Bjorn > --- > drivers/clk/qcom/gpucc-sdm845.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) > > diff --git a/drivers/clk/qcom/gpucc-sdm845.c b/drivers/clk/qcom/gpucc-sdm845.c > index 11222f487a65..7266e9a1d77e 100644 > --- a/drivers/clk/qcom/gpucc-sdm845.c > +++ b/drivers/clk/qcom/gpucc-sdm845.c > @@ -131,11 +131,37 @@ static struct gdsc gpu_cx_gdsc = { > .flags = VOTABLE, > }; > > +/* > + * 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. > + */ > +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 gpu_gx_gdsc = { > .gdscr = 0x100c, > .clamp_io_ctrl = 0x1508, > .pd = { > .name = "gpu_gx_gdsc", > + .power_on = gx_gdsc_enable, > }, > .pwrsts = PWRSTS_OFF_ON, > .flags = CLAMP_IO | AON_RESET | POLL_CFG_GDSCR, > -- > 2.18.0 >
diff --git a/drivers/clk/qcom/gpucc-sdm845.c b/drivers/clk/qcom/gpucc-sdm845.c index 11222f487a65..7266e9a1d77e 100644 --- a/drivers/clk/qcom/gpucc-sdm845.c +++ b/drivers/clk/qcom/gpucc-sdm845.c @@ -131,11 +131,37 @@ static struct gdsc gpu_cx_gdsc = { .flags = VOTABLE, }; +/* + * 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. + */ +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 gpu_gx_gdsc = { .gdscr = 0x100c, .clamp_io_ctrl = 0x1508, .pd = { .name = "gpu_gx_gdsc", + .power_on = gx_gdsc_enable, }, .pwrsts = PWRSTS_OFF_ON, .flags = CLAMP_IO | AON_RESET | POLL_CFG_GDSCR,
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 a dummy enable function for the GX gdsc to simulate success so that the pm_runtime reference counting is correct. Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> --- drivers/clk/qcom/gpucc-sdm845.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)