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/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2019 Western Digital Corporation or its affiliates.
*
* Authors:
* Anup Patel <anup.patel@wdc.com>
*/
#include <sbi/sbi_ecall.h>
#include <sbi/sbi_ecall_interface.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_trap.h>
#include <sbi/sbi_version.h>
#include <sbi/riscv_asm.h>
#define SBI_ECALL_VERSION_MAJOR 0
#define SBI_ECALL_VERSION_MINOR 2
#define SBI_OPENSBI_IMPID 1
u16 sbi_ecall_version_major(void)
{
return SBI_ECALL_VERSION_MAJOR;
}
u16 sbi_ecall_version_minor(void)
{
return SBI_ECALL_VERSION_MINOR;
}
static int sbi_ecall_base_probe(struct sbi_scratch *scratch,
unsigned long extid,
unsigned long *out_val)
{
struct sbi_ecall_extension *ext;
ext = sbi_ecall_find_extension(extid);
if (!ext) {
*out_val = 0;
return 0;
}
if (ext->probe)
return ext->probe(scratch, extid, out_val);
*out_val = 1;
return 0;
}
static int sbi_ecall_base_handler(struct sbi_scratch *scratch,
unsigned long extid, unsigned long funcid,
unsigned long *args, unsigned long *out_val,
struct sbi_trap_info *out_trap)
{
int ret = 0;
switch (funcid) {
case SBI_EXT_BASE_GET_SPEC_VERSION:
*out_val = (SBI_ECALL_VERSION_MAJOR <<
SBI_SPEC_VERSION_MAJOR_OFFSET) &
(SBI_SPEC_VERSION_MAJOR_MASK <<
SBI_SPEC_VERSION_MAJOR_OFFSET);
*out_val = *out_val | SBI_ECALL_VERSION_MINOR;
break;
case SBI_EXT_BASE_GET_IMP_ID:
*out_val = SBI_OPENSBI_IMPID;
break;
case SBI_EXT_BASE_GET_IMP_VERSION:
*out_val = OPENSBI_VERSION;
break;
case SBI_EXT_BASE_GET_MVENDORID:
*out_val = csr_read(CSR_MVENDORID);
break;
case SBI_EXT_BASE_GET_MARCHID:
*out_val = csr_read(CSR_MARCHID);
break;
case SBI_EXT_BASE_GET_MIMPID:
*out_val = csr_read(CSR_MIMPID);
break;
case SBI_EXT_BASE_PROBE_EXT:
ret = sbi_ecall_base_probe(scratch, args[0], out_val);
break;
default:
ret = SBI_ENOTSUPP;
}
return ret;
}
static struct sbi_ecall_extension ecall_base = {
.extid_start = SBI_EXT_BASE,
.extid_end = SBI_EXT_BASE,
.handle = sbi_ecall_base_handler,
};
static SBI_LIST_HEAD(ecall_exts_list);
struct sbi_ecall_extension *sbi_ecall_find_extension(unsigned long extid)
{
struct sbi_ecall_extension *t, *ret = NULL;
sbi_list_for_each_entry(t, &ecall_exts_list, head) {
if (t->extid_start <= extid && extid <= t->extid_end) {
ret = t;
break;
}
}
return ret;
}
int sbi_ecall_register_extension(struct sbi_ecall_extension *ext)
{
if (!ext || (ext->extid_end < ext->extid_start) || !ext->handle)
return SBI_EINVAL;
if (sbi_ecall_find_extension(ext->extid_start) ||
sbi_ecall_find_extension(ext->extid_end))
return SBI_EINVAL;
SBI_INIT_LIST_HEAD(&ext->head);
sbi_list_add_tail(&ext->head, &ecall_exts_list);
return 0;
}
void sbi_ecall_unregister_extension(struct sbi_ecall_extension *ext)
{
bool found = FALSE;
struct sbi_ecall_extension *t;
if (!ext)
return;
sbi_list_for_each_entry(t, &ecall_exts_list, head) {
if (t == ext) {
found = TRUE;
break;
}
}
if (found)
sbi_list_del_init(&ext->head);
}
int sbi_ecall_handler(u32 hartid, ulong mcause, struct sbi_trap_regs *regs,
struct sbi_scratch *scratch)
{
int ret = 0;
struct sbi_ecall_extension *ext;
unsigned long extension_id = regs->a7;
unsigned long func_id = regs->a6;
struct sbi_trap_info trap = {0};
unsigned long out_val;
bool is_0_1_spec = 0;
unsigned long args[6];
args[0] = regs->a0;
args[1] = regs->a1;
args[2] = regs->a2;
args[3] = regs->a3;
args[4] = regs->a4;
args[5] = regs->a5;
ext = sbi_ecall_find_extension(extension_id);
if (ext && ext->handle) {
ret = ext->handle(scratch, extension_id, func_id,
args, &out_val, &trap);
if (extension_id >= SBI_EXT_0_1_SET_TIMER &&
extension_id <= SBI_EXT_0_1_SHUTDOWN)
is_0_1_spec = 1;
} else {
ret = SBI_ENOTSUPP;
}
if (ret == SBI_ETRAP) {
trap.epc = regs->mepc;
sbi_trap_redirect(regs, &trap, scratch);
} else {
/* This function should return non-zero value only in case of
* fatal error. However, there is no good way to distinguish
* between a fatal and non-fatal errors yet. That's why we treat
* every return value except ETRAP as non-fatal and just return
* accordingly for now. Once fatal errors are defined, that
* case should be handled differently.
*/
regs->mepc += 4;
regs->a0 = ret;
if (!is_0_1_spec)
regs->a1 = out_val;
}
return 0;
}
int sbi_ecall_init(void)
{
int ret;
/* The order of below registrations is performance optimized */
ret = sbi_ecall_register_extension(&ecall_time);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_rfence);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_ipi);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_base);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_legacy);
if (ret)
return ret;
ret = sbi_ecall_register_extension(&ecall_vendor);
if (ret)
return ret;
return 0;
}
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