Re: [RFC PATCH 1/2] hw/riscv: sifive_u: Add file-backed OTP. softmmu/vl: add otp-file to boot option

[Paolo Bonzini]

On 28/07/20 04:02, Green Wan wrote:
> Hi Bin,
> 
> Thanks for the reply.
> 
> I think we can add property to sifive_u_otp_properties[] (something like
> below) and remove generic code dependency. What do you think of it?
> 
> @@ -243,6 +245,7 @@ static const MemoryRegionOps sifive_u_otp_ops = {
>  
>  static Property sifive_u_otp_properties[] = {
>      DEFINE_PROP_UINT32("serial", SiFiveUOTPState, serial, 0),
> +    DEFINE_PROP_STRING("otp_file", SiFiveUOTPState, otp_file),
>      DEFINE_PROP_END_OF_LIST(),
>  };
> 
>  typedef struct SiFiveUOTPState {
>      /*< private >*/
>      SysBusDevice parent_obj;
> @@ -77,6 +75,7 @@ typedef struct SiFiveUOTPState {
>      uint32_t fuse[SIFIVE_U_OTP_NUM_FUSES];
>      /* config */
>      uint32_t serial;
> +    char *otp_file;
>      uint32_t fuse_wo[SIFIVE_U_OTP_NUM_FUSES];
>  } SiFiveUOTPState;

Yes, I agree.  (Also, dashes are preferred to underscores these days).

You can also add an alias to the machine so that you can access this
with "-machine otp-file=...".

Paolo

> Regards,
> Green
> 
> 
> On Fri, Jul 24, 2020 at 10:20 PM Bin Meng <bmeng.cn@gmail.com
> <mailto:bmeng.cn@gmail.com>> wrote:
> 
>     Hi Green,
> 
>     On Fri, Jul 24, 2020 at 5:51 PM Green Wan <green.wan@sifive.com
>     <mailto:green.wan@sifive.com>> wrote:
>     >
>     > Add a file-backed implementation for OTP of sifive_u machine. Use
>     > '-boot otp-file=xxx' to enable it. Do file open, mmap and close
>     > for every OTP read/write in case keep the update-to-date snapshot
>     > of OTP.
>     >
>     > Signed-off-by: Green Wan <green.wan@sifive.com
>     <mailto:green.wan@sifive.com>>
>     > ---
>     >  hw/riscv/sifive_u_otp.c         | 88
>     ++++++++++++++++++++++++++++++++-
>     >  include/hw/riscv/sifive_u_otp.h |  2 +
>     >  qemu-options.hx                 |  3 +-
>     >  softmmu/vl.c                    |  6 ++-
>     >  4 files changed, 96 insertions(+), 3 deletions(-)
>     >
>     > diff --git a/hw/riscv/sifive_u_otp.c b/hw/riscv/sifive_u_otp.c
>     > index f6ecbaa2ca..26e1965821 100644
>     > --- a/hw/riscv/sifive_u_otp.c
>     > +++ b/hw/riscv/sifive_u_otp.c
>     > @@ -24,6 +24,72 @@
>     >  #include "qemu/log.h"
>     >  #include "qemu/module.h"
>     >  #include "hw/riscv/sifive_u_otp.h"
>     > +#include <stdio.h>
>     > +#include <stdlib.h>
>     > +#include <sys/types.h>
>     > +#include <sys/stat.h>
>     > +#include <unistd.h>
>     > +#include <fcntl.h>
>     > +#include <sys/mman.h>
>     > +#include <string.h>
>     > +
>     > +#define TRACE_PREFIX            "FU540_OTP: "
>     > +#define SIFIVE_FU540_OTP_SIZE   (SIFIVE_U_OTP_NUM_FUSES * 4)
>     > +
>     > +static int otp_backed_fd;
>     > +static unsigned int *otp_mmap;
>     > +
>     > +static void sifive_u_otp_backed_load(const char *filename);
>     > +static uint64_t sifive_u_otp_backed_read(uint32_t fuseidx);
>     > +static void sifive_u_otp_backed_write(uint32_t fuseidx,
>     > +                                      uint32_t paio,
>     > +                                      uint32_t pdin);
>     > +static void sifive_u_otp_backed_unload(void);
>     > +
>     > +void sifive_u_otp_backed_load(const char *filename)
>     > +{
>     > +    if (otp_backed_fd < 0) {
>     > +
>     > +        otp_backed_fd = open(filename, O_RDWR);
>     > +
>     > +        if (otp_backed_fd < 0)
>     > +            qemu_log_mask(LOG_TRACE,
>     > +                          TRACE_PREFIX "Warning: can't open otp
>     file\n");
>     > +        else {
>     > +
>     > +            otp_mmap = (unsigned int *)mmap(0,
>     > +                                            SIFIVE_FU540_OTP_SIZE,
>     > +                                            PROT_READ |
>     PROT_WRITE | PROT_EXEC,
>     > +                                            MAP_FILE | MAP_SHARED,
>     > +                                            otp_backed_fd,
>     > +                                            0);
>     > +
>     > +            if (otp_mmap == MAP_FAILED)
>     > +                qemu_log_mask(LOG_TRACE,
>     > +                              TRACE_PREFIX "Warning: can't mmap
>     otp file\n");
>     > +        }
>     > +    }
>     > +
>     > +}
>     > +
>     > +uint64_t sifive_u_otp_backed_read(uint32_t fuseidx)
>     > +{
>     > +    return (uint64_t)(otp_mmap[fuseidx]);
>     > +}
>     > +
>     > +void sifive_u_otp_backed_write(uint32_t fuseidx, uint32_t paio,
>     uint32_t pdin)
>     > +{
>     > +    otp_mmap[fuseidx] &= ~(pdin << paio);
>     > +    otp_mmap[fuseidx] |= (pdin << paio);
>     > +}
>     > +
>     > +
>     > +void sifive_u_otp_backed_unload(void)
>     > +{
>     > +    munmap(otp_mmap, SIFIVE_FU540_OTP_SIZE);
>     > +    close(otp_backed_fd);
>     > +    otp_backed_fd = -1;
>     > +}
>     >
>     >  static uint64_t sifive_u_otp_read(void *opaque, hwaddr addr,
>     unsigned int size)
>     >  {
>     > @@ -46,7 +112,17 @@ 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)) {
>     > -            return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
>     > +
>     > +            if (otp_file) {
>     > +                uint64_t val;
>     > +
>     > +                sifive_u_otp_backed_load(otp_file);
>     > +                val = sifive_u_otp_backed_read(s->pa);
>     > +                sifive_u_otp_backed_unload();
>     > +
>     > +                return val;
>     > +            } else
>     > +                return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
>     >          } else {
>     >              return 0xff;
>     >          }
>     > @@ -123,6 +199,12 @@ static void sifive_u_otp_write(void *opaque,
>     hwaddr addr,
>     >          s->ptrim = val32;
>     >          break;
>     >      case SIFIVE_U_OTP_PWE:
>     > +        if (otp_file) {
>     > +            sifive_u_otp_backed_load(otp_file);
>     > +            sifive_u_otp_backed_write(s->pa, s->paio, s->pdin);
>     > +            sifive_u_otp_backed_unload();
>     > +        }
>     > +
>     >          s->pwe = val32;
>     >          break;
>     >      default:
>     > @@ -165,6 +247,10 @@ static void sifive_u_otp_reset(DeviceState *dev)
>     >      /* Make a valid content of serial number */
>     >      s->fuse[SIFIVE_U_OTP_SERIAL_ADDR] = s->serial;
>     >      s->fuse[SIFIVE_U_OTP_SERIAL_ADDR + 1] = ~(s->serial);
>     > +
>     > +    /* Initialize file mmap and descriptor. */
>     > +    otp_mmap = NULL;
>     > +    otp_backed_fd = -1;
>     >  }
>     >
>     >  static void sifive_u_otp_class_init(ObjectClass *klass, void *data)
>     > diff --git a/include/hw/riscv/sifive_u_otp.h
>     b/include/hw/riscv/sifive_u_otp.h
>     > index 639297564a..1342bd7342 100644
>     > --- a/include/hw/riscv/sifive_u_otp.h
>     > +++ b/include/hw/riscv/sifive_u_otp.h
>     > @@ -52,6 +52,8 @@
>     >  #define SIFIVE_U_OTP(obj) \
>     >      OBJECT_CHECK(SiFiveUOTPState, (obj), TYPE_SIFIVE_U_OTP)
>     >
>     > +extern const char *otp_file;
>     > +
>     >  typedef struct SiFiveUOTPState {
>     >      /*< private >*/
>     >      SysBusDevice parent_obj;
>     > diff --git a/qemu-options.hx b/qemu-options.hx
>     > index 708583b4ce..eb9a54f4ed 100644
>     > --- a/qemu-options.hx
>     > +++ b/qemu-options.hx
>     > @@ -415,10 +415,11 @@ ERST
>     >
>     >  DEF("boot", HAS_ARG, QEMU_OPTION_boot,
>     >      "-boot [order=drives][,once=drives][,menu=on|off]\n"
>     > -    "     
>     
> [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n"
>     > +    "     
>     
> [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off][,otp-file=otp_file]\n"
>     >      "                'drives': floppy (a), hard disk (c), CD-ROM
>     (d), network (n)\n"
>     >      "                'sp_name': the file's name that would be
>     passed to bios as logo picture, if menu=on\n"
>     >      "                'sp_time': the period that splash picture
>     last if menu=on, unit is ms\n"
>     > +    "                'otp_file': the file name backed OTP\n"
>     >      "                'rb_timeout': the timeout before guest
>     reboot when boot failed, unit is ms\n",
> 
>     Instead of touching generic codes, could we add such property at the
>     board level?
> 
>     >      QEMU_ARCH_ALL)
>     >  SRST
> 
>     Regards,
>     Bin
>