Re: [RFC PATCH v2 1/2] hw/riscv: sifive_u: Add file-backed OTP.

[Green Wan <green.wan@sifive.com>]

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Hi Alistair,

Thanks for the feedback and tips. Not sure whether I get it right. I gave a
try with -drive and -device options as below.

$ qemu-system-riscv64 -M sifive_u -drive if=none,format=raw,file=otp.img
-device riscv.sifive.u.otp
qemu-system-riscv64: -device riscv.sifive.u.otp: Parameter 'driver' expects
pluggable device type

Then I dump "info qtree". The device, "riscv.sifive.u.otp", belongs to
'System' bus. (dump list by 'info qdm') and all devices on 'System' bus
seem not available with "-device". Any suggestions for specifying the
device?

Thanks,
- Green

On Tue, Aug 11, 2020 at 6:24 AM Alistair Francis <alistair23@gmail.com>
wrote:

> ,()On Thu, Jul 30, 2020 at 7:49 PM Green Wan <green.wan@sifive.com> wrote:
> >
> > Add a file-backed implementation for OTP of sifive_u machine. The
> > machine property for file-backed is disabled in default. Do file
> > open, mmap and close for every OTP read/write in case keep the
> > update-to-date snapshot of OTP.
>
> I don't think this is the correct way to write to the file.
>
> QEMU has backends that should do this for you. For example QEMU
> includes the -blockdev/-driver or -mtdblock command line arguments.
>
> This implementation should look more like an SD card in terms of
> interface. You will probably want to call drive_get_next() (probably
> with IF_MTD, but that's up to you).
>
> The hw/arm/xlnx-zcu102.c file has a good example of attaching an SD
> card by setting the drive property.
>
> Alistair
>
> >
> > Signed-off-by: Green Wan <green.wan@sifive.com>
> > ---
> >  hw/riscv/sifive_u.c             | 26 +++++++++++
> >  hw/riscv/sifive_u_otp.c         | 83 +++++++++++++++++++++++++++++++++
> >  include/hw/riscv/sifive_u.h     |  2 +
> >  include/hw/riscv/sifive_u_otp.h |  1 +
> >  4 files changed, 112 insertions(+)
> >
> > diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
> > index e5682c38a9..c818496918 100644
> > --- a/hw/riscv/sifive_u.c
> > +++ b/hw/riscv/sifive_u.c
> > @@ -87,6 +87,7 @@ static const struct MemmapEntry {
> >  };
> >
> >  #define OTP_SERIAL          1
> > +#define OTP_FILE            "NULL"
> >  #define GEM_REVISION        0x10070109
> >
> >  static void create_fdt(SiFiveUState *s, const struct MemmapEntry
> *memmap,
> > @@ -387,6 +388,8 @@ static void sifive_u_machine_init(MachineState
> *machine)
> >      object_initialize_child(OBJECT(machine), "soc", &s->soc,
> TYPE_RISCV_U_SOC);
> >      object_property_set_uint(OBJECT(&s->soc), "serial", s->serial,
> >                               &error_abort);
> > +    object_property_set_str(OBJECT(&s->soc), "otp-file", s->otp_file,
> > +                             &error_abort);
> >      qdev_realize(DEVICE(&s->soc), NULL, &error_abort);
> >
> >      /* register RAM */
> > @@ -526,6 +529,21 @@ static void sifive_u_machine_set_uint32_prop(Object
> *obj, Visitor *v,
> >      visit_type_uint32(v, name, (uint32_t *)opaque, errp);
> >  }
> >
> > +static void sifive_u_machine_get_str_prop(Object *obj, Visitor *v,
> > +                                             const char *name, void
> *opaque,
> > +                                             Error **errp)
> > +{
> > +    visit_type_str(v, name, (char **)opaque, errp);
> > +}
> > +
> > +static void sifive_u_machine_set_str_prop(Object *obj, Visitor *v,
> > +                                             const char *name, void
> *opaque,
> > +                                             Error **errp)
> > +{
> > +    visit_type_str(v, name, (char **)opaque, errp);
> > +}
> > +
> > +
> >  static void sifive_u_machine_instance_init(Object *obj)
> >  {
> >      SiFiveUState *s = RISCV_U_MACHINE(obj);
> > @@ -551,6 +569,12 @@ static void sifive_u_machine_instance_init(Object
> *obj)
> >                          sifive_u_machine_get_uint32_prop,
> >                          sifive_u_machine_set_uint32_prop, NULL,
> &s->serial);
> >      object_property_set_description(obj, "serial", "Board serial
> number");
> > +
> > +    s->otp_file = (char *)OTP_FILE;
> > +    object_property_add(obj, "otp-file", "string",
> > +                        sifive_u_machine_get_str_prop,
> > +                        sifive_u_machine_set_str_prop, NULL,
> &s->otp_file);
> > +    object_property_set_description(obj, "otp-file", "file-backed otp
> file");
> >  }
> >
> >  static void sifive_u_machine_class_init(ObjectClass *oc, void *data)
> > @@ -709,6 +733,7 @@ static void sifive_u_soc_realize(DeviceState *dev,
> Error **errp)
> >      }
> >
> >      qdev_prop_set_uint32(DEVICE(&s->otp), "serial", s->serial);
> > +    qdev_prop_set_string(DEVICE(&s->otp), "otp-file", s->otp_file);
> >      if (!sysbus_realize(SYS_BUS_DEVICE(&s->otp), errp)) {
> >          return;
> >      }
> > @@ -737,6 +762,7 @@ static void sifive_u_soc_realize(DeviceState *dev,
> Error **errp)
> >
> >  static Property sifive_u_soc_props[] = {
> >      DEFINE_PROP_UINT32("serial", SiFiveUSoCState, serial, OTP_SERIAL),
> > +    DEFINE_PROP_STRING("otp-file", SiFiveUSoCState, otp_file),
> >      DEFINE_PROP_END_OF_LIST()
> >  };
> >
> > diff --git a/hw/riscv/sifive_u_otp.c b/hw/riscv/sifive_u_otp.c
> > index f6ecbaa2ca..e359f30fdb 100644
> > --- a/hw/riscv/sifive_u_otp.c
> > +++ b/hw/riscv/sifive_u_otp.c
> > @@ -24,6 +24,62 @@
> >  #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 int32_t sifive_u_otp_backed_open(const char *filename, int32_t
> *fd,
> > +                                        uint32_t **map)
> > +{
> > +    /* open and mmap OTP image file */
> > +    if (filename && strcmp(filename, "NULL") != 0) {
> > +        *fd = open(filename, O_RDWR);
> > +
> > +        if (*fd < 0) {
> > +            qemu_log_mask(LOG_TRACE,
> > +                          TRACE_PREFIX "Warning: can't open otp
> file<%s>\n",
> > +                          filename);
> > +            return -1;
> > +        } else {
> > +
> > +            *map = (unsigned int *)mmap(0,
> > +                                         SIFIVE_FU540_OTP_SIZE,
> > +                                         PROT_READ | PROT_WRITE |
> PROT_EXEC,
> > +                                         MAP_FILE | MAP_SHARED,
> > +                                         *fd,
> > +                                         0);
> > +
> > +            if (*map == MAP_FAILED) {
> > +                qemu_log_mask(LOG_TRACE,
> > +                              TRACE_PREFIX "Warning: can't mmap otp
> file<%s>\n",
> > +                              filename);
> > +                close(*fd);
> > +                return -2;
> > +            }
> > +        }
> > +    } else {
> > +        /* filename is 'NULL' */
> > +        return -3;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static int32_t sifive_u_otp_backed_close(int fd, unsigned int *map)
> > +{
> > +    munmap(map, SIFIVE_FU540_OTP_SIZE);
> > +    close(fd);
> > +
> > +    return 0;
> > +}
> >
> >  static uint64_t sifive_u_otp_read(void *opaque, hwaddr addr, unsigned
> int size)
> >  {
> > @@ -46,6 +102,20 @@ 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)) {
> > +
> > +            int32_t fd;
> > +            uint32_t *map;
> > +            uint64_t val;
> > +
> > +            /* open and mmap OTP image file */
> > +            if (0 == sifive_u_otp_backed_open(s->otp_file, &fd, &map)) {
> > +                val = (uint64_t)(map[s->pa]);
> > +
> > +                /* close and unmmap */
> > +                sifive_u_otp_backed_close(fd, map);
> > +                return val;
> > +            }
> > +
> >              return s->fuse[s->pa & SIFIVE_U_OTP_PA_MASK];
> >          } else {
> >              return 0xff;
> > @@ -78,6 +148,8 @@ static void sifive_u_otp_write(void *opaque, hwaddr
> addr,
> >  {
> >      SiFiveUOTPState *s = opaque;
> >      uint32_t val32 = (uint32_t)val64;
> > +    int32_t fd;
> > +    uint32_t *map;
> >
> >      switch (addr) {
> >      case SIFIVE_U_OTP_PA:
> > @@ -123,6 +195,16 @@ static void sifive_u_otp_write(void *opaque, hwaddr
> addr,
> >          s->ptrim = val32;
> >          break;
> >      case SIFIVE_U_OTP_PWE:
> > +        /* open and mmap OTP image file */
> > +        if (0 == sifive_u_otp_backed_open(s->otp_file, &fd, &map)) {
> > +            /* store value */
> > +            map[s->pa] &= ~(s->pdin << s->paio);
> > +            map[s->pa] |= (s->pdin << s->paio);
> > +
> > +            /* close and unmmap */
> > +            sifive_u_otp_backed_close(fd, map);
> > +        }
> > +
> >          s->pwe = val32;
> >          break;
> >      default:
> > @@ -143,6 +225,7 @@ 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(),
> >  };
> >
> > diff --git a/include/hw/riscv/sifive_u.h b/include/hw/riscv/sifive_u.h
> > index aba4d0181f..966723da1d 100644
> > --- a/include/hw/riscv/sifive_u.h
> > +++ b/include/hw/riscv/sifive_u.h
> > @@ -46,6 +46,7 @@ typedef struct SiFiveUSoCState {
> >      CadenceGEMState gem;
> >
> >      uint32_t serial;
> > +    char *otp_file;
> >  } SiFiveUSoCState;
> >
> >  #define TYPE_RISCV_U_MACHINE MACHINE_TYPE_NAME("sifive_u")
> > @@ -65,6 +66,7 @@ typedef struct SiFiveUState {
> >      bool start_in_flash;
> >      uint32_t msel;
> >      uint32_t serial;
> > +    char *otp_file;
> >  } SiFiveUState;
> >
> >  enum {
> > diff --git a/include/hw/riscv/sifive_u_otp.h
> b/include/hw/riscv/sifive_u_otp.h
> > index 639297564a..f3d71ce82d 100644
> > --- a/include/hw/riscv/sifive_u_otp.h
> > +++ b/include/hw/riscv/sifive_u_otp.h
> > @@ -75,6 +75,7 @@ typedef struct SiFiveUOTPState {
> >      uint32_t fuse[SIFIVE_U_OTP_NUM_FUSES];
> >      /* config */
> >      uint32_t serial;
> > +    char *otp_file;
> >  } SiFiveUOTPState;
> >
> >  #endif /* HW_SIFIVE_U_OTP_H */
> > --
> > 2.17.1
> >
> >
>

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