1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | // Copyright (C) 2013 Broadcom Corporation |
3 | #include <linux/smp.h> |
4 | #include <linux/io.h> |
5 | #include <linux/ioport.h> |
6 | |
7 | #include <asm/cacheflush.h> |
8 | #include <linux/of_address.h> |
9 | |
10 | #include "bcm_kona_smc.h" |
11 | |
12 | static u32 bcm_smc_buffer_phys; /* physical address */ |
13 | static void __iomem *bcm_smc_buffer; /* virtual address */ |
14 | |
15 | struct bcm_kona_smc_data { |
16 | unsigned service_id; |
17 | unsigned arg0; |
18 | unsigned arg1; |
19 | unsigned arg2; |
20 | unsigned arg3; |
21 | unsigned result; |
22 | }; |
23 | |
24 | static const struct of_device_id bcm_kona_smc_ids[] __initconst = { |
25 | {.compatible = "brcm,kona-smc" }, |
26 | {.compatible = "bcm,kona-smc" }, /* deprecated name */ |
27 | {}, |
28 | }; |
29 | |
30 | /* Map in the args buffer area */ |
31 | int __init bcm_kona_smc_init(void) |
32 | { |
33 | struct device_node *node; |
34 | struct resource res; |
35 | int ret; |
36 | |
37 | /* Read buffer addr and size from the device tree node */ |
38 | node = of_find_matching_node(NULL, matches: bcm_kona_smc_ids); |
39 | if (!node) |
40 | return -ENODEV; |
41 | |
42 | ret = of_address_to_resource(dev: node, index: 0, r: &res); |
43 | of_node_put(node); |
44 | if (ret) |
45 | return -EINVAL; |
46 | |
47 | bcm_smc_buffer = ioremap(offset: res.start, size: resource_size(res: &res)); |
48 | if (!bcm_smc_buffer) |
49 | return -ENOMEM; |
50 | bcm_smc_buffer_phys = res.start; |
51 | |
52 | pr_info("Kona Secure API initialized\n" ); |
53 | |
54 | return 0; |
55 | } |
56 | |
57 | /* |
58 | * int bcm_kona_do_smc(u32 service_id, u32 buffer_addr) |
59 | * |
60 | * Only core 0 can run the secure monitor code. If an "smc" request |
61 | * is initiated on a different core it must be redirected to core 0 |
62 | * for execution. We rely on the caller to handle this. |
63 | * |
64 | * Each "smc" request supplies a service id and the address of a |
65 | * buffer containing parameters related to the service to be |
66 | * performed. A flags value defines the behavior of the level 2 |
67 | * cache and interrupt handling while the secure monitor executes. |
68 | * |
69 | * Parameters to the "smc" request are passed in r4-r6 as follows: |
70 | * r4 service id |
71 | * r5 flags (SEC_ROM_*) |
72 | * r6 physical address of buffer with other parameters |
73 | * |
74 | * Execution of an "smc" request produces two distinct results. |
75 | * |
76 | * First, the secure monitor call itself (regardless of the specific |
77 | * service request) can succeed, or can produce an error. When an |
78 | * "smc" request completes this value is found in r12; it should |
79 | * always be SEC_EXIT_NORMAL. |
80 | * |
81 | * In addition, the particular service performed produces a result. |
82 | * The values that should be expected depend on the service. We |
83 | * therefore return this value to the caller, so it can handle the |
84 | * request result appropriately. This result value is found in r0 |
85 | * when the "smc" request completes. |
86 | */ |
87 | static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys) |
88 | { |
89 | register u32 ip asm("ip" ); /* Also called r12 */ |
90 | register u32 r0 asm("r0" ); |
91 | register u32 r4 asm("r4" ); |
92 | register u32 r5 asm("r5" ); |
93 | register u32 r6 asm("r6" ); |
94 | |
95 | r4 = service_id; |
96 | r5 = 0x3; /* Keep IRQ and FIQ off in SM */ |
97 | r6 = buffer_phys; |
98 | |
99 | asm volatile ( |
100 | /* Make sure we got the registers we want */ |
101 | __asmeq("%0" , "ip" ) |
102 | __asmeq("%1" , "r0" ) |
103 | __asmeq("%2" , "r4" ) |
104 | __asmeq("%3" , "r5" ) |
105 | __asmeq("%4" , "r6" ) |
106 | ".arch_extension sec\n" |
107 | " smc #0\n" |
108 | : "=r" (ip), "=r" (r0) |
109 | : "r" (r4), "r" (r5), "r" (r6) |
110 | : "r1" , "r2" , "r3" , "r7" , "lr" ); |
111 | |
112 | BUG_ON(ip != SEC_EXIT_NORMAL); |
113 | |
114 | return r0; |
115 | } |
116 | |
117 | /* __bcm_kona_smc() should only run on CPU 0, with pre-emption disabled */ |
118 | static void __bcm_kona_smc(void *info) |
119 | { |
120 | struct bcm_kona_smc_data *data = info; |
121 | u32 __iomem *args = bcm_smc_buffer; |
122 | |
123 | BUG_ON(smp_processor_id() != 0); |
124 | BUG_ON(!args); |
125 | |
126 | /* Copy the four 32 bit argument values into the bounce area */ |
127 | writel_relaxed(data->arg0, args++); |
128 | writel_relaxed(data->arg1, args++); |
129 | writel_relaxed(data->arg2, args++); |
130 | writel(val: data->arg3, addr: args); |
131 | |
132 | /* Flush caches for input data passed to Secure Monitor */ |
133 | flush_cache_all(); |
134 | |
135 | /* Trap into Secure Monitor and record the request result */ |
136 | data->result = bcm_kona_do_smc(service_id: data->service_id, buffer_phys: bcm_smc_buffer_phys); |
137 | } |
138 | |
139 | unsigned bcm_kona_smc(unsigned service_id, unsigned arg0, unsigned arg1, |
140 | unsigned arg2, unsigned arg3) |
141 | { |
142 | struct bcm_kona_smc_data data; |
143 | |
144 | data.service_id = service_id; |
145 | data.arg0 = arg0; |
146 | data.arg1 = arg1; |
147 | data.arg2 = arg2; |
148 | data.arg3 = arg3; |
149 | data.result = 0; |
150 | |
151 | /* |
152 | * Due to a limitation of the secure monitor, we must use the SMP |
153 | * infrastructure to forward all secure monitor calls to Core 0. |
154 | */ |
155 | smp_call_function_single(cpuid: 0, func: __bcm_kona_smc, info: &data, wait: 1); |
156 | |
157 | return data.result; |
158 | } |
159 | |