On Thu, Feb 8, 2024 at 10:21 AM Peter Griffin <peter.griffin@xxxxxxxxxx> wrote: > > Some Exynos based SoCs like Tensor gs101 protect the PMU registers for > security hardening reasons so that they are only write accessible in el3 > via an SMC call. > > As most Exynos drivers that need to write PMU registers currently obtain a > regmap via syscon (phys, pinctrl, watchdog). Support for the above usecase > is implemented in this driver using a custom regmap similar to syscon to > handle the SMC call. Platforms that don't secure PMU registers, get a mmio > regmap like before. As regmaps abstract out the underlying register access > changes to the leaf drivers are minimal. > > A new API exynos_get_pmu_regmap_by_phandle() is provided for leaf drivers > that currently use syscon_regmap_lookup_by_phandle(). This also handles > deferred probing. > > Signed-off-by: Peter Griffin <peter.griffin@xxxxxxxxxx> > --- > Changes since v3: > - Fix PMUALIVE_MASK > - Add TENSOR_ prefix > - clear SET_BITS bits on each loop iteration > - change set_bit to set_bits in func name > - Fix some alignment > - Add missing return on dev_err_probe > - Reduce indentation in loop > > Changes since v2 > - Add select REGMAP to Kconfig > - Add constant for SET/CLEAR bits > - Replace kerneldoc with one line comment > - Fix kerneldoc for EXPORT_SYMBOL_GPL funcs > - remove superfluous extern keyword > - dev_err_probe() on probe error > - shorten regmcfg name > - no compatibles inside probe, use match data > - don't mix declarations with/without initializations > - tensor_sec_reg_read() use mmio to avoid access restrictions > - Collect up Reviewed-by > - const for regmap_config structs > --- Tested-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx> Tested on my E850-96. All modules that use PMU are still functional with this patch (watchdog, USB host and Ethernet). No regressions. [snip]
