Re: [PATCH v3 08/10] RISC-V: Add auxiliary files

[Daniel Kiper]

On Wed, Nov 14, 2018 at 06:27:37PM +0100, Alexander Graf wrote:
> To support a new architecture we need to provide a few helper functions
> for memory, cache, timer, etc support.
>
> This patch adds the remainders of those. Some bits are still disabled,
> as I couldn't guarantee that we're always running on models / in modes
> where the respective hardware is available.
>
> Signed-off-by: Alexander Graf <address@hidden>
>
> ---
>
> v2 -> v3:
>
>   - Fix riscv32 target
> ---
>  grub-core/kern/riscv/cache.c       | 64 +++++++++++++++++++++++++++++
>  grub-core/kern/riscv/cache_flush.S | 40 +++++++++++++++++++
>  grub-core/kern/riscv/efi/init.c    | 82 
> ++++++++++++++++++++++++++++++++++++++
>  include/grub/riscv32/efi/memory.h  |  6 +++
>  include/grub/riscv32/time.h        | 28 +++++++++++++
>  include/grub/riscv32/types.h       | 34 ++++++++++++++++
>  include/grub/riscv64/efi/memory.h  |  6 +++
>  include/grub/riscv64/time.h        | 28 +++++++++++++
>  include/grub/riscv64/types.h       | 34 ++++++++++++++++
>  9 files changed, 322 insertions(+)
>  create mode 100644 grub-core/kern/riscv/cache.c
>  create mode 100644 grub-core/kern/riscv/cache_flush.S
>  create mode 100644 grub-core/kern/riscv/efi/init.c
>  create mode 100644 include/grub/riscv32/efi/memory.h
>  create mode 100644 include/grub/riscv32/time.h
>  create mode 100644 include/grub/riscv32/types.h
>  create mode 100644 include/grub/riscv64/efi/memory.h
>  create mode 100644 include/grub/riscv64/time.h
>  create mode 100644 include/grub/riscv64/types.h
>
> diff --git a/grub-core/kern/riscv/cache.c b/grub-core/kern/riscv/cache.c
> new file mode 100644
> index 000000000..15dbe6927
> --- /dev/null
> +++ b/grub-core/kern/riscv/cache.c
> @@ -0,0 +1,64 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2013  Free Software Foundation, Inc.

s/2013/2018/

> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/cache.h>
> +#include <grub/misc.h>
> +
> +static grub_int64_t dlinesz;
> +static grub_int64_t ilinesz;
> +
> +/* Prototypes for asm functions. */
> +void grub_arch_clean_dcache_range (grub_addr_t beg, grub_addr_t end,
> +                                grub_size_t line_size);
> +void grub_arch_invalidate_icache_range (grub_addr_t beg, grub_addr_t end,
> +                                     grub_size_t line_size);
> +
> +static void
> +probe_caches (void)
> +{
> +  /* TODO */
> +  dlinesz = 32;
> +  ilinesz = 32;
> +}
> +
> +void
> +grub_arch_sync_caches (void *address, grub_size_t len)
> +{
> +  grub_size_t start, end, max_align;
> +
> +  if (dlinesz == 0)
> +    probe_caches();
> +  if (dlinesz == 0)
> +    grub_fatal ("Unknown cache line size!");
> +
> +  max_align = dlinesz > ilinesz ? dlinesz : ilinesz;
> +
> +  start = ALIGN_DOWN ((grub_size_t) address, max_align);
> +  end = ALIGN_UP ((grub_size_t) address + len, max_align);
> +
> +  grub_arch_clean_dcache_range (start, end, dlinesz);
> +  grub_arch_invalidate_icache_range (start, end, ilinesz);
> +}
> +
> +void
> +grub_arch_sync_dma_caches (volatile void *address, grub_size_t len)
> +{
> +  /* DMA incoherent devices not supported yet */
> +  if (address || len || 1)
> +    return;

I think that you can drop the code and leave the comment here.

> +}
> diff --git a/grub-core/kern/riscv/cache_flush.S 
> b/grub-core/kern/riscv/cache_flush.S
> new file mode 100644
> index 000000000..033a8aac3
> --- /dev/null
> +++ b/grub-core/kern/riscv/cache_flush.S
> @@ -0,0 +1,40 @@
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2013  Free Software Foundation, Inc.
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/symbol.h>
> +
> +     .file   "cache_flush.S"
> +     .text
> +
> +/*
> + * Simple cache maintenance functions
> + */
> +
> +// a0 - *beg (inclusive)
> +// a1 - *end (exclusive)
> +// a2 - line size

Please do not use "//" for comments.

> +FUNCTION(grub_arch_clean_dcache_range)
> +     // TODO
> +     ret
> +
> +// a0 - *beg (inclusive)
> +// a1 - *end (exclusive)
> +// a2 - line size

Ditto.

> +FUNCTION(grub_arch_invalidate_icache_range)
> +     // TODO

Ditto.

> +     ret
> diff --git a/grub-core/kern/riscv/efi/init.c b/grub-core/kern/riscv/efi/init.c
> new file mode 100644
> index 000000000..199de08a7
> --- /dev/null
> +++ b/grub-core/kern/riscv/efi/init.c
> @@ -0,0 +1,82 @@
> +/* init.c - initialize a riscv-based EFI system */
> +/*
> + *  GRUB  --  GRand Unified Bootloader
> + *  Copyright (C) 2013 Free Software Foundation, Inc.
> + *
> + *  GRUB is free software: you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation, either version 3 of the License, or
> + *  (at your option) any later version.
> + *
> + *  GRUB is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + *  You should have received a copy of the GNU General Public License
> + *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <grub/env.h>
> +#include <grub/kernel.h>
> +#include <grub/misc.h>
> +#include <grub/mm.h>
> +#include <grub/time.h>
> +#include <grub/efi/efi.h>
> +#include <grub/loader.h>
> +
> +static grub_uint64_t timer_frequency_in_khz;
> +
> +static grub_uint64_t
> +grub_efi_get_time_ms (void)
> +{
> +  grub_uint64_t tmr;
> +
> +#if 0
> +#if __riscv_xlen == 64
> +  asm volatile ("rdtime %0" : "=r" (tmr));
> +#else
> +  grub_uint32_t lo, hi, tmp;
> +  asm volatile (
> +    "1:\n"
> +    "rdtimeh %0\n"
> +    "rdtime %1\n"
> +    "rdtimeh %2\n"
> +    "bne %0, %2, 1b"
> +    : "=&r" (hi), "=&r" (lo), "=&r" (tmp));
> +  tmr = ((u64)hi << 32) | lo;
> +#endif

I would drop this piece of dead code.

> +#else
> +  static grub_uint64_t val;
> +  tmr = val++;
> +#endif
> +
> +  return tmr / timer_frequency_in_khz;

Could not you use val instead of tmr here?

Daniel