1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2015,2019 The Linux Foundation. All rights reserved. 3 */ 4 5 #include <linux/io.h> 6 #include <linux/errno.h> 7 #include <linux/delay.h> 8 #include <linux/mutex.h> 9 #include <linux/slab.h> 10 #include <linux/types.h> 11 #include <linux/qcom_scm.h> 12 #include <linux/arm-smccc.h> 13 #include <linux/dma-mapping.h> 14 15 #include "qcom_scm.h" 16 17 /** 18 * struct arm_smccc_args 19 * @args: The array of values used in registers in smc instruction 20 */ 21 struct arm_smccc_args { 22 unsigned long args[8]; 23 }; 24 25 static DEFINE_MUTEX(qcom_scm_lock); 26 27 #define QCOM_SCM_EBUSY_WAIT_MS 30 28 #define QCOM_SCM_EBUSY_MAX_RETRY 20 29 30 #define SCM_SMC_N_REG_ARGS 4 31 #define SCM_SMC_FIRST_EXT_IDX (SCM_SMC_N_REG_ARGS - 1) 32 #define SCM_SMC_N_EXT_ARGS (MAX_QCOM_SCM_ARGS - SCM_SMC_N_REG_ARGS + 1) 33 #define SCM_SMC_FIRST_REG_IDX 2 34 #define SCM_SMC_LAST_REG_IDX (SCM_SMC_FIRST_REG_IDX + SCM_SMC_N_REG_ARGS - 1) 35 36 static void __scm_smc_do_quirk(const struct arm_smccc_args *smc, 37 struct arm_smccc_res *res) 38 { 39 unsigned long a0 = smc->args[0]; 40 struct arm_smccc_quirk quirk = { .id = ARM_SMCCC_QUIRK_QCOM_A6 }; 41 42 quirk.state.a6 = 0; 43 44 do { 45 arm_smccc_smc_quirk(a0, smc->args[1], smc->args[2], 46 smc->args[3], smc->args[4], smc->args[5], 47 quirk.state.a6, smc->args[7], res, &quirk); 48 49 if (res->a0 == QCOM_SCM_INTERRUPTED) 50 a0 = res->a0; 51 52 } while (res->a0 == QCOM_SCM_INTERRUPTED); 53 } 54 55 static void __scm_smc_do(const struct arm_smccc_args *smc, 56 struct arm_smccc_res *res, bool atomic) 57 { 58 int retry_count = 0; 59 60 if (atomic) { 61 __scm_smc_do_quirk(smc, res); 62 return; 63 } 64 65 do { 66 mutex_lock(&qcom_scm_lock); 67 68 __scm_smc_do_quirk(smc, res); 69 70 mutex_unlock(&qcom_scm_lock); 71 72 if (res->a0 == QCOM_SCM_V2_EBUSY) { 73 if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY) 74 break; 75 msleep(QCOM_SCM_EBUSY_WAIT_MS); 76 } 77 } while (res->a0 == QCOM_SCM_V2_EBUSY); 78 } 79 80 int scm_smc_call(struct device *dev, const struct qcom_scm_desc *desc, 81 struct qcom_scm_res *res, bool atomic) 82 { 83 int arglen = desc->arginfo & 0xf; 84 int i; 85 dma_addr_t args_phys = 0; 86 void *args_virt = NULL; 87 size_t alloc_len; 88 gfp_t flag = atomic ? GFP_ATOMIC : GFP_KERNEL; 89 u32 smccc_call_type = atomic ? ARM_SMCCC_FAST_CALL : ARM_SMCCC_STD_CALL; 90 u32 qcom_smccc_convention = 91 (qcom_scm_convention == SMC_CONVENTION_ARM_32) ? 92 ARM_SMCCC_SMC_32 : ARM_SMCCC_SMC_64; 93 struct arm_smccc_res smc_res; 94 struct arm_smccc_args smc = {0}; 95 96 smc.args[0] = ARM_SMCCC_CALL_VAL( 97 smccc_call_type, 98 qcom_smccc_convention, 99 desc->owner, 100 SCM_SMC_FNID(desc->svc, desc->cmd)); 101 smc.args[1] = desc->arginfo; 102 for (i = 0; i < SCM_SMC_N_REG_ARGS; i++) 103 smc.args[i + SCM_SMC_FIRST_REG_IDX] = desc->args[i]; 104 105 if (unlikely(arglen > SCM_SMC_N_REG_ARGS)) { 106 alloc_len = SCM_SMC_N_EXT_ARGS * sizeof(u64); 107 args_virt = kzalloc(PAGE_ALIGN(alloc_len), flag); 108 109 if (!args_virt) 110 return -ENOMEM; 111 112 if (qcom_smccc_convention == ARM_SMCCC_SMC_32) { 113 __le32 *args = args_virt; 114 115 for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++) 116 args[i] = cpu_to_le32(desc->args[i + 117 SCM_SMC_FIRST_EXT_IDX]); 118 } else { 119 __le64 *args = args_virt; 120 121 for (i = 0; i < SCM_SMC_N_EXT_ARGS; i++) 122 args[i] = cpu_to_le64(desc->args[i + 123 SCM_SMC_FIRST_EXT_IDX]); 124 } 125 126 args_phys = dma_map_single(dev, args_virt, alloc_len, 127 DMA_TO_DEVICE); 128 129 if (dma_mapping_error(dev, args_phys)) { 130 kfree(args_virt); 131 return -ENOMEM; 132 } 133 134 smc.args[SCM_SMC_LAST_REG_IDX] = args_phys; 135 } 136 137 __scm_smc_do(&smc, &smc_res, atomic); 138 139 if (args_virt) { 140 dma_unmap_single(dev, args_phys, alloc_len, DMA_TO_DEVICE); 141 kfree(args_virt); 142 } 143 144 if (res) { 145 res->result[0] = smc_res.a1; 146 res->result[1] = smc_res.a2; 147 res->result[2] = smc_res.a3; 148 } 149 150 return (long)smc_res.a0 ? qcom_scm_remap_error(smc_res.a0) : 0; 151 } 152