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
__scm_smc_do_quirk(const struct arm_smccc_args * smc,struct arm_smccc_res * res)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
__scm_smc_do(const struct arm_smccc_args * smc,struct arm_smccc_res * res,bool atomic)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
scm_smc_call(struct device * dev,const struct qcom_scm_desc * desc,struct qcom_scm_res * res,bool atomic)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
