Re: [RFC PATCH v7 2/2] hw/misc/sifive_u_otp: Add backend drive support

[Bin Meng]

On Thu, Oct 15, 2020 at 12:15 PM Green Wan <green.wan@sifive.com> wrote:
>
> Add '-drive' support to OTP device. Allow users to assign a raw file
> as OTP image.
>
> test commands for 16k otp.img filled with zero:
>
> $ dd if=/dev/zero of=./otp.img bs=1k count=16
> $ ./qemu-system-riscv64 -M sifive_u -m 256M -nographic -bios none \
> -kernel ../opensbi/build/platform/sifive/fu540/firmware/fw_payload.elf \
> -d guest_errors -drive if=none,format=raw,file=otp.img
>
> Signed-off-by: Green Wan <green.wan@sifive.com>
> ---
>  hw/misc/sifive_u_otp.c         | 67 +++++++++++++++++++++++++++++++++-
>  include/hw/misc/sifive_u_otp.h |  2 +
>  2 files changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/hw/misc/sifive_u_otp.c b/hw/misc/sifive_u_otp.c
> index 565eec082f..60066375ab 100644
> --- a/hw/misc/sifive_u_otp.c
> +++ b/hw/misc/sifive_u_otp.c
> @@ -19,11 +19,14 @@
>   */
>
>  #include "qemu/osdep.h"
> +#include "qapi/error.h"
>  #include "hw/qdev-properties.h"
>  #include "hw/sysbus.h"
>  #include "qemu/log.h"
>  #include "qemu/module.h"
>  #include "hw/misc/sifive_u_otp.h"
> +#include "sysemu/blockdev.h"
> +#include "sysemu/block-backend.h"
>
>  #define WRITTEN_BIT_ON 0x1
>
> @@ -54,6 +57,16 @@ static uint64_t sifive_u_otp_read(void *opaque, hwaddr 
> addr, unsigned int size)
>          if ((s->pce & SIFIVE_U_OTP_PCE_EN) &&
>              (s->pdstb & SIFIVE_U_OTP_PDSTB_EN) &&
>              (s->ptrim & SIFIVE_U_OTP_PTRIM_EN)) {
> +
> +            /* read from backend */
> +            if (s->blk) {
> +                int32_t buf;
> +
> +                blk_pread(s->blk, s->pa * SIFIVE_U_OTP_FUSE_WORD, &buf,
> +                          SIFIVE_U_OTP_FUSE_WORD);
> +                return buf;
> +            }
> +
>              return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
>          } else {
>              return 0xff;
> @@ -137,7 +150,7 @@ static void sifive_u_otp_write(void *opaque, hwaddr addr,
>          if (s->pwe && !s->pas) {
>              if (GET_FUSEARRAY_BIT(s->fuse_wo, s->pa, s->paio)) {
>                  qemu_log_mask(LOG_GUEST_ERROR,
> -                              "Error: write idx<%u>, bit<%u>\n",
> +                              "write once error: idx<%u>, bit<%u>\n",

This should be in the patch 1.

>                                s->pa, s->paio);
>                  break;
>              }
> @@ -145,6 +158,12 @@ static void sifive_u_otp_write(void *opaque, hwaddr addr,
>              /* write bit data */
>              SET_FUSEARRAY_BIT(s->fuse, s->pa, s->paio, s->pdin);
>
> +            /* write to backend */
> +            if (s->blk) {
> +                blk_pwrite(s->blk, s->pa * SIFIVE_U_OTP_FUSE_WORD,
> +                           &s->fuse[s->pa], SIFIVE_U_OTP_FUSE_WORD, 0);
> +            }
> +
>              /* update written bit */
>              SET_FUSEARRAY_BIT(s->fuse_wo, s->pa, s->paio, WRITTEN_BIT_ON);
>          }
> @@ -168,16 +187,48 @@ static const MemoryRegionOps sifive_u_otp_ops = {
>
>  static Property sifive_u_otp_properties[] = {
>      DEFINE_PROP_UINT32("serial", SiFiveUOTPState, serial, 0),
> +    DEFINE_PROP_DRIVE("drive", SiFiveUOTPState, blk),
>      DEFINE_PROP_END_OF_LIST(),
>  };
>

Otherwise,
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Tested-by: Bin Meng <bin.meng@windriver.com>

You can drop the "RFC" tag in the next version.