Hi Prabhakar, On Thu, Oct 20, 2022 at 12:02 AM Prabhakar <prabhakar.csengg@xxxxxxxxx> wrote: > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> > > On the AX45MP core, cache coherency is a specification option so it may > not be supported. In this case DMA will fail. As a workaround, firstly we > allocate a global dma coherent pool from which DMA allocations are taken > and marked as non-cacheable + bufferable using the PMA region as specified > in the device tree. Synchronization callbacks are implemented to > synchronize when doing DMA transactions. > > The Andes AX45MP core has a Programmable Physical Memory Attributes (PMA) > block that allows dynamic adjustment of memory attributes in the runtime. > It contains a configurable amount of PMA entries implemented as CSR > registers to control the attributes of memory locations in interest. > > Below are the memory attributes supported: > * Device, Non-bufferable > * Device, bufferable > * Memory, Non-cacheable, Non-bufferable > * Memory, Non-cacheable, Bufferable > * Memory, Write-back, No-allocate > * Memory, Write-back, Read-allocate > * Memory, Write-back, Write-allocate > * Memory, Write-back, Read and Write-allocate > > This patch adds support to configure the memory attributes of the memory > regions as passed from the l2 cache node and exposes the cache management > ops. > > More info about PMA (section 10.3): > http://www.andestech.com/wp-content/uploads/AX45MP-1C-Rev.-5.0.0-Datasheet.pdf > > This feature is based on the work posted [0] by Vincent Chen > <vincentc@xxxxxxxxxxxxx> for the Andes AndeStart RISC-V CPU. > > [0] https://lore.kernel.org/lkml/1540982130-28248-1-git-send-email-vincentc@xxxxxxxxxxxxx/ > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> Thanks for your patch! > --- a/arch/riscv/include/asm/errata_list.h > +++ b/arch/riscv/include/asm/errata_list.h > @@ -89,6 +89,7 @@ asm volatile(ALTERNATIVE( \ > #define ALT_THEAD_PMA(_val) > #endif > > +#ifdef CONFIG_ERRATA_THEAD_CMO > /* > * dcache.ipa rs1 (invalidate, physical address) > * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 | > @@ -143,5 +144,6 @@ asm volatile(ALTERNATIVE_2( \ > : "a0") > > #endif /* __ASSEMBLY__ */ > +#endif FTR, the new #endif should be above the old #endif. I noticed because after rebasing on top of commit 65e9fb081877a18c ("drivers/perf: riscv_pmu_sbi: add support for PMU variant on T-Head C9xx cores") in riscv/for-next, the build failed because the new ALT_SBI_PMU_OVERFLOW() definition ended up inside both #endifs, instead of between. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
