[PATCH v5 3/3] platform: generic: renesas: rzfive: Add SBI EXT to check for enabling IOCP errata

[Yu-Chien Peter Lin <peterlin@andestech.com>]

On Mon, Feb 20, 2023 at 09:01:32PM +0530, Anup Patel wrote:
> On Tue, Feb 14, 2023 at 3:21 AM Lad Prabhakar
> <prabhakar.mahadev-lad.rj@bp.renesas.com> wrote:
> >
> > I/O Coherence Port (IOCP) provides an AXI interface for connecting
> > external non-caching masters, such as DMA controllers. The accesses
> > from IOCP are coherent with D-Caches and L2 Cache.
> >
> > IOCP is a specification option and is disabled on the Renesas RZ/Five
> > SoC due to this reason IP blocks using DMA will fail.
> >
> > As a workaround for SoCs with IOCP disabled CMO needs to be handled by
> > software. Firstly OpenSBI configures the memory region as
> > "Memory, Non-cacheable, Bufferable" and passes this region as a global
> > shared dma pool as a DT node. With DMA_GLOBAL_POOL enabled all DMA
> > allocations happen from this region and synchronization callbacks are
> > implemented to synchronize when doing DMA transactions.
> >
> > RENESAS_RZFIVE_SBI_EXT_IOCP_SW_WORKAROUND SBI EXT checks if the IOCP
> > errata should be applied to handle cache management.
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > Reviewed-by: Yu Chien Peter Lin <peterlin@andestech.com>
> > ---
> >  platform/generic/include/andes/andes45.h | 25 +++++++++++++--
> >  platform/generic/renesas/rzfive/rzfive.c | 41 ++++++++++++++++++++++++
> >  2 files changed, 64 insertions(+), 2 deletions(-)
> >
> > diff --git a/platform/generic/include/andes/andes45.h b/platform/generic/include/andes/andes45.h
> > index 08b3d18..d5d265f 100644
> > --- a/platform/generic/include/andes/andes45.h
> > +++ b/platform/generic/include/andes/andes45.h
> > @@ -4,7 +4,28 @@
> >  #define CSR_MARCHID_MICROID 0xfff
> >
> >  /* Memory and Miscellaneous Registers */
> > -#define CSR_MCACHE_CTL 0x7ca
> > -#define CSR_MCCTLCOMMAND 0x7cc
> > +#define CSR_MCACHE_CTL         0x7ca
> > +#define CSR_MCCTLCOMMAND       0x7cc
> > +#define CSR_MICM_CFG           0xfc0
> > +#define CSR_MDCM_CFG           0xfc1
> > +#define CSR_MMSC_CFG           0xfc2
> > +
> > +#define MISA_20_OFFSET                 20
> > +#define MISA_20_MASK                   (0x1 << MISA_20_OFFSET)
> > +
> > +#define MICM_CFG_ISZ_OFFSET            6
> > +#define MICM_CFG_ISZ_MASK              (0x7  << MICM_CFG_ISZ_OFFSET)
> > +
> > +#define MDCM_CFG_DSZ_OFFSET            6
> > +#define MDCM_CFG_DSZ_MASK              (0x7  << MDCM_CFG_DSZ_OFFSET)
> > +
> > +#define MMSC_CFG_CCTLCSR_OFFSET                16
> > +#define MMSC_CFG_CCTLCSR_MASK          (0x1 << MMSC_CFG_CCTLCSR_OFFSET)
> > +#define MMSC_IOCP_OFFSET                       47
> > +#define MMSC_IOCP_MASK                 (0x1ULL << MMSC_IOCP_OFFSET)
> > +
> > +#define MCACHE_CTL_CCTL_SUEN_OFFSET    8
> > +#define MCACHE_CTL_CCTL_SUEN_MASK      (0x1 << MCACHE_CTL_CCTL_SUEN_OFFSET)
> > +
> >
> >  #endif /* _RISCV_ANDES45_H */
> > diff --git a/platform/generic/renesas/rzfive/rzfive.c b/platform/generic/renesas/rzfive/rzfive.c
> > index 4d71d0d..9530d28 100644
> > --- a/platform/generic/renesas/rzfive/rzfive.c
> > +++ b/platform/generic/renesas/rzfive/rzfive.c
> > @@ -4,11 +4,14 @@
> >   *
> >   */
> >
> > +#include <andes/andes45.h>
> >  #include <andes/andes45_pma.h>
> >  #include <platform_override.h>
> >  #include <sbi/sbi_domain.h>
> >  #include <sbi_utils/fdt/fdt_helper.h>
> >
> > +#define RENESAS_RZFIVE_SBI_EXT_IOCP_SW_WORKAROUND      0
> 
> The SBI vendor extension_id will be the same for all SoCs based on Andes
> CPUs so the function_id space will be shared across all such SoCs.
> 
> How does Andes plan to manage the function_id space of SBI vendor extension ?
> 
> I suggest the following:
> 1) The function_id == 0 can be used to return an SoC identifier. For example,
>      Renesas RzFive can have an SoC identifier "0".
> 2) Move RENESAS_RZFIVE_SBI_EXT_IOCP_SW_WORKAROUND to a
>     separate header at platform/generic/include/andes/andes_sbi.h and
>     change it's value to "1"
> 
> The above suggestion will help multiple SoC with Andes CPU share same
> SBI function_id space for SBI vendor extension.
> 
> Regards,
> Anup

Hi Anup,

Does this mean that all the SoC using Andes CPUs must have a unique
fid for each vendor SBI call function? If so, how do we make the new
vendors aware of this rule? As this won't be defined in the SBI spec.

The fid#0 - fid#24 have been used in our production code, as long as
the renesas_rzfive_vendor_ext_provider hook only gets called when the
root node compatible string is "renesas,r9a07g043f01", the functions
will be invoked correctly even though the fid conflicts with other
Andes SoCs?

Best regards,
Peter Lin