[PATCH 1/6] lib: utils/timer: Add ACLINT MTIMER library
Xiang W
wxjstz at 126.com
Wed Jun 23 02:06:33 PDT 2021
在 2021-06-23星期三的 10:35 +0530，Anup Patel写道：
> On Mon, Jun 14, 2021 at 8:17 PM Xiang W <wxjstz at 126.com> wrote:
> >
> > 在 2021-06-12星期六的 21:33 +0530，Anup Patel写道：
> > > We add common ACLINT MTIMER library similar to the CLINT library
> > > so that OpenSBI platforms can use it.
> > >
> > > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > > ---
> > > include/sbi_utils/timer/aclint_mtimer.h | 41 ++++++
> > > lib/utils/timer/aclint_mtimer.c | 180
> > > ++++++++++++++++++++++++
> > > lib/utils/timer/objects.mk | 1 +
> > > 3 files changed, 222 insertions(+)
> > > create mode 100644 include/sbi_utils/timer/aclint_mtimer.h
> > > create mode 100644 lib/utils/timer/aclint_mtimer.c
> > >
> > > diff --git a/include/sbi_utils/timer/aclint_mtimer.h
> > > b/include/sbi_utils/timer/aclint_mtimer.h
> > > new file mode 100644
> > > index 0000000..510bfa9
> > > --- /dev/null
> > > +++ b/include/sbi_utils/timer/aclint_mtimer.h
> > > @@ -0,0 +1,41 @@
> > > +/*
> > > + * SPDX-License-Identifier: BSD-2-Clause
> > > + *
> > > + * Copyright (c) 2021 Western Digital Corporation or its
> > > affiliates.
> > > + *
> > > + * Authors:
> > > + * Anup Patel <anup.patel at wdc.com>
> > > + */
> > > +
> > > +#ifndef __TIMER_ACLINT_MTIMER_H__
> > > +#define __TIMER_ACLINT_MTIMER_H__
> > > +
> > > +#include <sbi/sbi_types.h>
> > > +
> > > +#define ACLINT_MTIMER_ALIGN 0x1000
> > > +#define ACLINT_MTIMER_SIZE 0x8000
> > > +#define ACLINT_MTIMER_MAX_HARTS 4095
> > > +
> > > +#define CLINT_MTIMER_OFFSET 0x4000
> > > +
> > > +struct aclint_mtimer_data {
> > > + /* Public details */
> > > + unsigned long addr;
> > > + unsigned long size;
> > > + u32 first_hartid;
> > > + u32 hart_count;
> > > + bool has_64bit_mmio;
> > > + /* Private details (initialized and used by ACLINT MTIMER
> > > library) */
> > > + struct aclint_mtimer_data *time_delta_reference;
> > > + unsigned long time_delta_computed;
> > > + u64 time_delta;
> > > + u64 (*time_rd)(volatile u64 *addr);
> > > + void (*time_wr)(u64 value, volatile u64 *addr);
> > > +};
> > > +
> > > +int aclint_mtimer_warm_init(void);
> > > +
> > > +int aclint_mtimer_cold_init(struct aclint_mtimer_data *mt,
> > > + struct aclint_mtimer_data
> > > *reference);
> > > +
> > > +#endif
> > > diff --git a/lib/utils/timer/aclint_mtimer.c
> > > b/lib/utils/timer/aclint_mtimer.c
> > > new file mode 100644
> > > index 0000000..2c64ca8
> > > --- /dev/null
> > > +++ b/lib/utils/timer/aclint_mtimer.c
> > > @@ -0,0 +1,180 @@
> > > +/*
> > > + * SPDX-License-Identifier: BSD-2-Clause
> > > + *
> > > + * Copyright (c) 2021 Western Digital Corporation or its
> > > affiliates.
> > > + *
> > > + * Authors:
> > > + * Anup Patel <anup.patel at wdc.com>
> > > + */
> > > +
> > > +#include <sbi/riscv_asm.h>
> > > +#include <sbi/riscv_atomic.h>
> > > +#include <sbi/riscv_io.h>
> > > +#include <sbi/sbi_domain.h>
> > > +#include <sbi/sbi_error.h>
> > > +#include <sbi/sbi_hartmask.h>
> > > +#include <sbi/sbi_ipi.h>
> > > +#include <sbi/sbi_timer.h>
> > > +#include <sbi_utils/timer/aclint_mtimer.h>
> > > +
> > > +#define MTIMER_CMP_OFF 0x0000
> > > +#define MTIMER_VAL_OFF 0x7ff8
> > > +
> > > +static struct aclint_mtimer_data
> > > *mtimer_hartid2data[SBI_HARTMASK_MAX_BITS];
> > > +
> > > +#if __riscv_xlen != 32
> > > +static u64 mtimer_time_rd64(volatile u64 *addr)
> > > +{
> > > + return readq_relaxed(addr);
> > > +}
> > > +
> > > +static void mtimer_time_wr64(u64 value, volatile u64 *addr)
> > > +{
> > > + writeq_relaxed(value, addr);
> > > +}
> > > +#endif
> > > +
> > > +static u64 mtimer_time_rd32(volatile u64 *addr)
> > > +{
> > > + u32 lo, hi;
> > > +
> > > + do {
> > > + hi = readl_relaxed((u32 *)addr + 1);
> > > + lo = readl_relaxed((u32 *)addr);
> > > + } while (hi != readl_relaxed((u32 *)addr + 1));
> > > +
> > > + return ((u64)hi << 32) | (u64)lo;
> > > +}
> > > +
> > > +static void mtimer_time_wr32(u64 value, volatile u64 *addr)
> > > +{
> > > + u32 mask = -1U;
> > > +
> > > + writel_relaxed(value & mask, (void *)(addr));
> > > + writel_relaxed(value >> 32, (void *)(addr) + 0x04);
> > I recommend writing like this
> > writel_relaxed(0, (void *)(addr));
> > writel_relaxed(value >> 32, (void *)(addr) + 0x04);
> > writel_relaxed(value & mask, (void *)(addr));
>
> Yes, certainly this is more appropriate sequence but the
> RISC-V privilege spec says to write -1U instead of 0 in
> the first write.
>
> Refer, "section 3.2.1 Machine Timer Registers (mtime and
> mtimecmp)" in the RISC-V privilege spec.
>
The example in the manual is to prevent MTIMECMP from less than the
original value or less than the value to be written. And MTIMECMP is
not a counter and does not change. My suggestion is to prevent changes
during write, causing the value of the counter and expected
inconsistency after writing completion.
Regards,
Xiang W
> >
> > Reviewed-by: Xiang W <wxjstz at 126.com>
>
> Regards,
> Anup
>
> > > +}
> > > +
> > > +static u64 mtimer_value(void)
> > > +{
> > > + struct aclint_mtimer_data *mt =
> > > mtimer_hartid2data[current_hartid()];
> > > + u64 *time_val = ((void *)mt->addr) + MTIMER_VAL_OFF;
> > > +
> > > + /* Read MTIMER Time Value */
> > > + return mt->time_rd(time_val) + mt->time_delta;
> > > +}
> > > +
> > > +static void mtimer_event_stop(void)
> > > +{
> > > + u32 target_hart = current_hartid();
> > > + struct aclint_mtimer_data *mt =
> > > mtimer_hartid2data[target_hart];
> > > + u64 *time_cmp = (void *)mt->addr + MTIMER_CMP_OFF;
> > > +
> > > + /* Clear MTIMER Time Compare */
> > > + mt->time_wr(-1ULL, &time_cmp[target_hart - mt-
> > > > first_hartid]);
> > > +}
> > > +
> > > +static void mtimer_event_start(u64 next_event)
> > > +{
> > > + u32 target_hart = current_hartid();
> > > + struct aclint_mtimer_data *mt =
> > > mtimer_hartid2data[target_hart];
> > > + u64 *time_cmp = (void *)mt->addr + MTIMER_CMP_OFF;
> > > +
> > > + /* Program MTIMER Time Compare */
> > > + mt->time_wr(next_event - mt->time_delta,
> > > + &time_cmp[target_hart - mt->first_hartid]);
> > > +}
> > > +
> > > +static struct sbi_timer_device mtimer = {
> > > + .name = "aclint-mtimer",
> > > + .timer_value = mtimer_value,
> > > + .timer_event_start = mtimer_event_start,
> > > + .timer_event_stop = mtimer_event_stop
> > > +};
> > > +
> > > +int aclint_mtimer_warm_init(void)
> > > +{
> > > + u64 v1, v2, mv;
> > > + u32 target_hart = current_hartid();
> > > + struct aclint_mtimer_data *reference;
> > > + u64 *mt_time_val, *mt_time_cmp, *ref_time_val;
> > > + struct aclint_mtimer_data *mt =
> > > mtimer_hartid2data[target_hart];
> > > +
> > > + if (!mt)
> > > + return SBI_ENODEV;
> > > +
> > > + /*
> > > + * Compute delta if reference available
> > > + *
> > > + * We deliberately compute time_delta in warm init so
> > > that
> > > time_delta
> > > + * is computed on a HART which is going to use given
> > > MTIMER.
> > > We use
> > > + * atomic flag timer_delta_computed to ensure that only
> > > one
> > > HART does
> > > + * time_delta computation.
> > > + */
> > > + if (mt->time_delta_reference) {
> > > + reference = mt->time_delta_reference;
> > > + mt_time_val = (void *)mt->addr + MTIMER_VAL_OFF;
> > > + ref_time_val = (void *)reference->addr +
> > > MTIMER_VAL_OFF;
> > > + if (!atomic_raw_xchg_ulong(&mt-
> > > >time_delta_computed,
> > > 1)) {
> > > + v1 = mt->time_rd(mt_time_val);
> > > + mv = reference->time_rd(ref_time_val);
> > > + v2 = mt->time_rd(mt_time_val);
> > > + mt->time_delta = mv - ((v1 / 2) + (v2 /
> > > 2));
> > > + }
> > > + }
> > > +
> > > + /* Clear Time Compare */
> > > + mt_time_cmp = (void *)mt->addr + MTIMER_CMP_OFF;
> > > + mt->time_wr(-1ULL, &mt_time_cmp[target_hart - mt-
> > > > first_hartid]);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +int aclint_mtimer_cold_init(struct aclint_mtimer_data *mt,
> > > + struct aclint_mtimer_data *reference)
> > > +{
> > > + u32 i;
> > > + int rc;
> > > + unsigned long pos, region_size;
> > > + struct sbi_domain_memregion reg;
> > > +
> > > + /* Sanity checks */
> > > + if (!mt || (mt->addr & (ACLINT_MTIMER_ALIGN - 1)) ||
> > > + (mt->size < ACLINT_MTIMER_SIZE) ||
> > > + (mt->first_hartid >= SBI_HARTMASK_MAX_BITS) ||
> > > + (mt->hart_count > ACLINT_MTIMER_MAX_HARTS))
> > > + return SBI_EINVAL;
> > > +
> > > + /* Initialize private data */
> > > + mt->time_delta_reference = reference;
> > > + mt->time_delta_computed = 0;
> > > + mt->time_delta = 0;
> > > + mt->time_rd = mtimer_time_rd32;
> > > + mt->time_wr = mtimer_time_wr32;
> > > +
> > > + /* Override read/write accessors for 64bit MMIO */
> > > +#if __riscv_xlen != 32
> > > + if (mt->has_64bit_mmio) {
> > > + mt->time_rd = mtimer_time_rd64;
> > > + mt->time_wr = mtimer_time_wr64;
> > > + }
> > > +#endif
> > > +
> > > + /* Update MTIMER hartid table */
> > > + for (i = 0; i < mt->hart_count; i++)
> > > + mtimer_hartid2data[mt->first_hartid + i] = mt;
> > > +
> > > + /* Add MTIMER regions to the root domain */
> > > + for (pos = 0; pos < mt->size; pos += ACLINT_MTIMER_ALIGN)
> > > {
> > > + region_size = ((mt->size - pos) <
> > > ACLINT_MTIMER_ALIGN) ?
> > > + (mt->size - pos) :
> > > ACLINT_MTIMER_ALIGN;
> > > + sbi_domain_memregion_init(mt->addr + pos,
> > > region_size,
> > > +
> > > SBI_DOMAIN_MEMREGION_MMIO,
> > > ®);
> > > + rc = sbi_domain_root_add_memregion(®);
> > > + if (rc)
> > > + return rc;
> > > + }
> > > +
> > > + sbi_timer_set_device(&mtimer);
> > > +
> > > + return 0;
> > > +}
> > > diff --git a/lib/utils/timer/objects.mk
> > > b/lib/utils/timer/objects.mk
> > > index 1b84e92..f8e3931 100644
> > > --- a/lib/utils/timer/objects.mk
> > > +++ b/lib/utils/timer/objects.mk
> > > @@ -9,3 +9,4 @@
> > >
> > > libsbiutils-objs-y += timer/fdt_timer.o
> > > libsbiutils-objs-y += timer/fdt_timer_clint.o
> > > +libsbiutils-objs-y += timer/aclint_mtimer.o
> > > --
> > > 2.25.1
> > >
> > >
> >
> >
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