[PATCH 2/2] lib: utils/sys: Extend HTIF library to allow custom base address
Anup Patel
apatel at ventanamicro.com
Sat Jan 8 03:44:44 PST 2022
On Sat, Jan 8, 2022 at 2:38 PM Dong Du <dd_nirvana at sjtu.edu.cn> wrote:
>
>
>
> On Jan 8, 2022, at 12:03 PM, Anup Patel apatel at ventanamicro.com wrote:
>
> > Some of RISC-V emulators provide HTIF at fixed base address so for
> > such emulators users have to hard-code HTIF base address in the
> > linker script.
> >
> > To address this problem, we let users optionally provide fixed HTIF
> > base address via platform support (or device tree).
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> > include/sbi_utils/sys/htif.h | 4 +-
> > lib/utils/reset/fdt_reset_htif.c | 8 +++-
> > lib/utils/serial/fdt_serial_htif.c | 8 +++-
> > lib/utils/sys/htif.c | 74 ++++++++++++++++++++++++++----
> > 4 files changed, 80 insertions(+), 14 deletions(-)
> >
> > diff --git a/include/sbi_utils/sys/htif.h b/include/sbi_utils/sys/htif.h
> > index 9cc9634..106a096 100644
> > --- a/include/sbi_utils/sys/htif.h
> > +++ b/include/sbi_utils/sys/htif.h
> > @@ -10,8 +10,8 @@
> >
> > #include <sbi/sbi_types.h>
> >
> > -int htif_serial_init(void);
> > +int htif_serial_init(bool custom_base, unsigned long custom_base_addr);
> >
> > -int htif_system_reset_init(void);
> > +int htif_system_reset_init(bool custom_base, unsigned long custom_base_addr);
> >
> > #endif
> > diff --git a/lib/utils/reset/fdt_reset_htif.c b/lib/utils/reset/fdt_reset_htif.c
> > index dd08660..ab55198 100644
> > --- a/lib/utils/reset/fdt_reset_htif.c
> > +++ b/lib/utils/reset/fdt_reset_htif.c
> > @@ -14,7 +14,13 @@
> > static int htif_reset_init(void *fdt, int nodeoff,
> > const struct fdt_match *match)
> > {
> > - return htif_system_reset_init();
> > + bool custom;
> > + uint64_t addr = 0;
> > +
> > + custom = fdt_get_node_addr_size(fdt, nodeoff, 0, &addr, NULL) ?
> > + false : true;
> > +
> > + return htif_system_reset_init(custom, addr);
> > }
> >
> > static const struct fdt_match htif_reset_match[] = {
> > diff --git a/lib/utils/serial/fdt_serial_htif.c
> > b/lib/utils/serial/fdt_serial_htif.c
> > index fae55b8..e8bdbb4 100644
> > --- a/lib/utils/serial/fdt_serial_htif.c
> > +++ b/lib/utils/serial/fdt_serial_htif.c
> > @@ -19,7 +19,13 @@ static const struct fdt_match serial_htif_match[] = {
> > static int serial_htif_init(void *fdt, int nodeoff,
> > const struct fdt_match *match)
> > {
> > - return htif_serial_init();
> > + bool custom;
> > + uint64_t addr = 0;
> > +
> > + custom = fdt_get_node_addr_size(fdt, nodeoff, 0, &addr, NULL) ?
> > + false : true;
> > +
> > + return htif_serial_init(custom, addr);
> > }
> >
> > struct fdt_serial fdt_serial_htif = {
> > diff --git a/lib/utils/sys/htif.c b/lib/utils/sys/htif.c
> > index 7c69c7f..fbee4c7 100644
> > --- a/lib/utils/sys/htif.c
> > +++ b/lib/utils/sys/htif.c
> > @@ -7,6 +7,7 @@
> >
> > #include <sbi/riscv_locks.h>
> > #include <sbi/sbi_console.h>
> > +#include <sbi/sbi_error.h>
> > #include <sbi/sbi_system.h>
> > #include <sbi_utils/sys/htif.h>
> >
> > @@ -47,15 +48,45 @@
> >
> > volatile uint64_t tohost __attribute__((section(".htif")));
> > volatile uint64_t fromhost __attribute__((section(".htif")));
> > +
> > +static uint64_t *htif_base = NULL;
> > +static bool htif_have_base = false;
> > +
> > static int htif_console_buf;
> > static spinlock_t htif_lock = SPIN_LOCK_INITIALIZER;
> >
> > +static inline uint64_t __read_tohost(void)
> > +{
> > + return (htif_have_base) ? htif_base[1] : tohost;
> > +}
> > +
> > +static inline void __write_tohost(uint64_t val)
> > +{
> > + if (htif_have_base)
> > + htif_base[1] = val;
> > + else
> > + tohost = val;
> > +}
> > +
> > +static inline uint64_t __read_fromhost(void)
> > +{
> > + return (htif_have_base) ? htif_base[0] : fromhost;
> > +}
> > +
> > +static inline void __write_fromhost(uint64_t val)
> > +{
> > + if (htif_have_base)
> > + htif_base[0] = val;
> > + else
> > + fromhost = val;
> > +}
> > +
> > static void __check_fromhost()
> > {
> > - uint64_t fh = fromhost;
> > + uint64_t fh = __read_fromhost();
> > if (!fh)
> > return;
> > - fromhost = 0;
> > + __write_fromhost(0);
> >
> > /* this should be from the console */
> > if (FROMHOST_DEV(fh) != HTIF_DEV_CONSOLE)
> > @@ -73,9 +104,22 @@ static void __check_fromhost()
> >
> > static void __set_tohost(uint64_t dev, uint64_t cmd, uint64_t data)
> > {
> > - while (tohost)
> > + while (__read_tohost())
> > __check_fromhost();
> > - tohost = TOHOST_CMD(dev, cmd, data);
> > + __write_tohost(TOHOST_CMD(dev, cmd, data));
> > +}
> > +
> > +static int set_custom_base(bool custom_base, unsigned long custom_base_addr)
> > +{
> > + if (custom_base) {
> > + if (htif_have_base &&
> > + custom_base_addr != (unsigned long)htif_base)
>
> The above could be simplified to: if (htif_have_base)
If we only check htif_have_base then it fails to boot because
set_custom_base() is called from two places htif_serial_init()
and htif_reset_init(). The second check prevents failure when
same address is set twice.
>
> > + return SBI_EINVAL;
> > + htif_have_base = true;
> > + htif_base = (uint64_t *)custom_base_addr;
>
> Minor suggestion: it would be better to set the value (htif_base) before setting the flag (htif_have_base).
The order does not matter here because set_custom_base()
is always called in the cold boot path but I will change it anyway.
I think we can make set_custom_base() even more generic by
allowing separate addresses for "fromhost" and "tohost". I will
update this in the next revision.
Regards,
Anup
>
> Besides the above minor issues, looks good to me.
>
> Reviewed-by: Dong Du <Dd_nirvana at sjtu.edu.cn>
>
> Regards,
> Dong
>
> > + }
> > +
> > + return 0;
> > }
> >
> > #if __riscv_xlen == 32
> > @@ -148,10 +192,15 @@ static struct sbi_console_device htif_console = {
> > .console_getc = htif_getc
> > };
> >
> > -int htif_serial_init(void)
> > +int htif_serial_init(bool custom_base, unsigned long custom_base_addr)
> > {
> > - sbi_console_set_device(&htif_console);
> > + int rc;
> > +
> > + rc = set_custom_base(custom_base, custom_base_addr);
> > + if (rc)
> > + return rc;
> >
> > + sbi_console_set_device(&htif_console);
> > return 0;
> > }
> >
> > @@ -163,8 +212,8 @@ static int htif_system_reset_check(u32 type, u32 reason)
> > static void htif_system_reset(u32 type, u32 reason)
> > {
> > while (1) {
> > - fromhost = 0;
> > - tohost = 1;
> > + __write_fromhost(0);
> > + __write_tohost(1);
> > }
> > }
> >
> > @@ -174,9 +223,14 @@ static struct sbi_system_reset_device htif_reset = {
> > .system_reset = htif_system_reset
> > };
> >
> > -int htif_system_reset_init(void)
> > +int htif_system_reset_init(bool custom_base, unsigned long custom_base_addr)
> > {
> > - sbi_system_reset_add_device(&htif_reset);
> > + int rc;
> > +
> > + rc = set_custom_base(custom_base, custom_base_addr);
> > + if (rc)
> > + return rc;
> >
> > + sbi_system_reset_add_device(&htif_reset);
> > return 0;
> > }
> > --
> > 2.25.1
> >
> >
> > --
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