qcom_scm-smc.c
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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2015,2019 The Linux Foundation. All rights reserved.
*/
#include <linux/io.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/qcom_scm.h>
#include <linux/arm-smccc.h>
#include <linux/dma-mapping.h>
#include "qcom_scm.h"
/**
* struct arm_smccc_args
* @args: The array of values used in registers in smc instruction
*/
struct arm_smccc_args {
unsigned long args[8];
};
static DEFINE_MUTEX(qcom_scm_lock);
#define QCOM_SCM_EBUSY_WAIT_MS 30
#define QCOM_SCM_EBUSY_MAX_RETRY 20
#define SCM_SMC_N_REG_ARGS 4
#define SCM_SMC_FIRST_EXT_IDX (SCM_SMC_N_REG_ARGS - 1)
#define SCM_SMC_N_EXT_ARGS (MAX_QCOM_SCM_ARGS - SCM_SMC_N_REG_ARGS + 1)
#define SCM_SMC_FIRST_REG_IDX 2
#define SCM_SMC_LAST_REG_IDX (SCM_SMC_FIRST_REG_IDX + SCM_SMC_N_REG_ARGS - 1)
static void __scm_smc_do_quirk(const struct arm_smccc_args *smc,
struct arm_smccc_res *res)
{
unsigned long a0 = smc->args[0];
struct arm_smccc_quirk quirk = { .id = ARM_SMCCC_QUIRK_QCOM_A6 };
quirk.state.a6 = 0;
do {
arm_smccc_smc_quirk(a0, smc->args[1], smc->args[2],
smc->args[3], smc->args[4], smc->args[5],
quirk.state.a6, smc->args[7], res, &quirk);
if (res->a0 == QCOM_SCM_INTERRUPTED)
a0 = res->a0;
} while (res->a0 == QCOM_SCM_INTERRUPTED);
}
static void __scm_smc_do(const struct arm_smccc_args *smc,
struct arm_smccc_res *res, bool atomic)
{
int retry_count = 0;
if (atomic) {
__scm_smc_do_quirk(smc, res);
return;
}
do {
mutex_lock(&qcom_scm_lock);
__scm_smc_do_quirk(smc, res);
mutex_unlock(&qcom_scm_lock);
if (res->a0 == QCOM_SCM_V2_EBUSY) {
if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
break;
msleep(QCOM_SCM_EBUSY_WAIT_MS);
}
} while (res->a0 == QCOM_SCM_V2_EBUSY);
}
int scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res, bool atomic)
{
int arglen = desc->arginfo & 0xf;
int i;
dma_addr_t args_phys = 0;
void *args_virt = NULL;
size_t alloc_len;
gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL;
u32 smccc_call_type = atomic ? ARM_SMCCC_FAST_CALL : ARM_SMCCC_STD_CALL;
u32 qcom_smccc_convention =
(qcom_scm_convention == SMC_CONVENTION_ARM_32) ?
ARM_SMCCC_SMC_32 : ARM_SMCCC_SMC_64;
struct arm_smccc_res smc_res;
struct arm_smccc_args smc = {0};
smc.args[0] = ARM_SMCCC_CALL_VAL(
smccc_call_type,
qcom_smccc_convention,
desc->owner,
SCM_SMC_FNID(desc->svc, desc->cmd));
smc.args[1] = desc->arginfo;
for (i = 0; i < SCM_SMC_N_REG_ARGS; i++)
smc.args[i + SCM_SMC_FIRST_REG_IDX] = desc->args[i];
if (unlikely(arglen > SCM_SMC_N_REG_ARGS)) {
alloc_len = SCM_SMC_N_EXT_ARGS * sizeof(u64);
args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag);
if (!args_virt)
return -ENOMEM;
if (qcom_smccc_convention == ARM_SMCCC_SMC_32) {
__le32 *args = args_virt;
for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++)
args[i] = cpu_to_le32(desc->args[i +
SCM_SMC_FIRST_EXT_IDX]);
} else {
__le64 *args = args_virt;
for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++)
args[i] = cpu_to_le64(desc->args[i +
SCM_SMC_FIRST_EXT_IDX]);
}
args_phys = dma_map_single(dev, args_virt, alloc_len,
DMA_TO_DEVICE);
if (dma_mapping_error(dev, args_phys)) {
kfree(args_virt);
return -ENOMEM;
}
smc.args[SCM_SMC_LAST_REG_IDX] = args_phys;
}
__scm_smc_do(&smc, &smc_res, atomic);
if (args_virt) {
dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE);
kfree(args_virt);
}
if (res) {
res->result[0] = smc_res.a1;
res->result[1] = smc_res.a2;
res->result[2] = smc_res.a3;
}
return (long)smc_res.a0 ? qcom_scm_remap_error(smc_res.a0) : 0;
}