On Sun, 3 Jul 2022 at 22:10, Krzysztof Kozlowski
<krzysztof.kozlowski@xxxxxxxxxx> wrote:
>
> On 02/07/2022 23:37, Sam Protsenko wrote:
> > SysMMU v7 can have Virtual Machine registers, which implement multiple
> > translation domains. The driver should know if it's true or not, as VM
> > registers shouldn't be accessed if not present. Read corresponding
> > capabilities register to obtain that info, and store it in driver data.
> >
> > Signed-off-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> > ---
> > drivers/iommu/exynos-iommu.c | 42 ++++++++++++++++++++++++++++++------
> > 1 file changed, 36 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
> > index 28f8c8d93aa3..df6ddbebbe2b 100644
> > --- a/drivers/iommu/exynos-iommu.c
> > +++ b/drivers/iommu/exynos-iommu.c
> > @@ -135,6 +135,9 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
> > #define CFG_SYSSEL (1 << 22) /* System MMU 3.2 only */
> > #define CFG_FLPDCACHE (1 << 20) /* System MMU 3.2+ only */
> >
> > +#define CAPA0_CAPA1_EXIST BIT(11)
> > +#define CAPA1_VCR_ENABLED BIT(14)
> > +
> > /* common registers */
> > #define REG_MMU_CTRL 0x000
> > #define REG_MMU_CFG 0x004
> > @@ -171,6 +174,10 @@ static u32 lv2ent_offset(sysmmu_iova_t iova)
> > #define REG_V5_FAULT_AR_VA 0x070
> > #define REG_V5_FAULT_AW_VA 0x080
> >
> > +/* v7.x registers */
> > +#define REG_V7_CAPA0 0x870
> > +#define REG_V7_CAPA1 0x874
> > +
> > #define has_sysmmu(dev) (dev_iommu_priv_get(dev) != NULL)
> >
> > static struct device *dma_dev;
> > @@ -274,6 +281,9 @@ struct sysmmu_drvdata {
> > unsigned int version; /* our version */
> >
> > struct iommu_device iommu; /* IOMMU core handle */
> > +
> > + /* v7 fields */
> > + bool has_vcr; /* virtual machine control register */
> > };
> >
> > static struct exynos_iommu_domain *to_exynos_domain(struct iommu_domain *dom)
> > @@ -364,11 +374,7 @@ static void __sysmmu_disable_clocks(struct sysmmu_drvdata *data)
> >
> > static void __sysmmu_get_version(struct sysmmu_drvdata *data)
> > {
> > - u32 ver;
> > -
> > - __sysmmu_enable_clocks(data);
> > -
> > - ver = readl(data->sfrbase + REG_MMU_VERSION);
> > + const u32 ver = readl(data->sfrbase + REG_MMU_VERSION);
>
>
> No need for const for local, non-pointer variables. There is no benefit
> in preventing the modification and it is not a constant.
>
I'd say it's more a matter of taste, having "const" kinda disciplines
one. But I don't mind removing those bits, will do in v2.
> >
> > /* controllers on some SoCs don't report proper version */
> > if (ver == 0x80000001u)
> > @@ -378,6 +384,29 @@ static void __sysmmu_get_version(struct sysmmu_drvdata *data)
> >
> > dev_dbg(data->sysmmu, "hardware version: %d.%d\n",
> > MMU_MAJ_VER(data->version), MMU_MIN_VER(data->version));
> > +}
> > +
> > +static bool __sysmmu_has_capa1(struct sysmmu_drvdata *data)
> > +{
> > + const u32 capa0 = readl(data->sfrbase + REG_V7_CAPA0);
>
> Same here and further.
>
>
> Best regards,
> Krzysztof
