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 wrote: > ,()On Thu, Jul 30, 2020 at 7:49 PM Green Wan 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 > > --- > > 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 > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +#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 > > > > >