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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,
- enum qcom_scm_convention qcom_convention,
- 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_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;
- }
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