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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"
#define SCM_SMC_FNID(s, c) ((((s) & 0xFF) << 8) | ((c) & 0xFF))
/**
* struct arm_smccc_args
* @args: The array of values used in registers in smc instruction
*/
struct arm_smccc_args {
unsigned long args[8];
};
static u64 qcom_smccc_convention = -1;
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);
}
static 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;
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;
}
/**
* qcom_scm_call() - Invoke a syscall in the secure world
* @dev: device
* @svc_id: service identifier
* @cmd_id: command identifier
* @desc: Descriptor structure containing arguments and return values
*
* Sends a command to the SCM and waits for the command to finish processing.
* This should *only* be called in pre-emptible context.
*/
int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
might_sleep();
return __scm_smc_call(dev, desc, res, false);
}
/**
* qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
* @dev: device
* @svc_id: service identifier
* @cmd_id: command identifier
* @desc: Descriptor structure containing arguments and return values
* @res: Structure containing results from SMC/HVC call
*
* Sends a command to the SCM and waits for the command to finish processing.
* This can be called in atomic context.
*/
int qcom_scm_call_atomic(struct device *dev, const struct qcom_scm_desc *desc,
struct qcom_scm_res *res)
{
return __scm_smc_call(dev, desc, res, true);
}
int __qcom_scm_is_call_available(struct device *dev, u32 svc_id, u32 cmd_id)
{
int ret;
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.owner = ARM_SMCCC_OWNER_SIP,
};
struct qcom_scm_res res;
desc.arginfo = QCOM_SCM_ARGS(1);
desc.args[0] = SCM_SMC_FNID(svc_id, cmd_id) |
(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT);
ret = qcom_scm_call(dev, &desc, &res);
return ret ? : res.result[0];
}
void __qcom_scm_init(void)
{
struct qcom_scm_desc desc = {
.svc = QCOM_SCM_SVC_INFO,
.cmd = QCOM_SCM_INFO_IS_CALL_AVAIL,
.args[0] = SCM_SMC_FNID(QCOM_SCM_SVC_INFO,
QCOM_SCM_INFO_IS_CALL_AVAIL) |
(ARM_SMCCC_OWNER_SIP << ARM_SMCCC_OWNER_SHIFT),
.arginfo = QCOM_SCM_ARGS(1),
.owner = ARM_SMCCC_OWNER_SIP,
};
struct qcom_scm_res res;
int ret;
qcom_smccc_convention = ARM_SMCCC_SMC_64;
// Device isn't required as there is only one argument - no device
// needed to dma_map_single to secure world
ret = qcom_scm_call_atomic(NULL, &desc, &res);
if (!ret && res.result[0] == 1)
goto out;
qcom_smccc_convention = ARM_SMCCC_SMC_32;
ret = qcom_scm_call_atomic(NULL, &desc, &res);
if (!ret && res.result[0] == 1)
goto out;
qcom_smccc_convention = -1;
BUG();
out:
pr_info("QCOM SCM SMC Convention: %lld\n", qcom_smccc_convention);
}
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