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
12static u32		bcm_smc_buffer_phys;	/* physical address */
13static void __iomem	*bcm_smc_buffer;	/* virtual address */
14
15struct 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
24static 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 */
31int __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, bcm_kona_smc_ids);
39	if (!node)
40		return -ENODEV;
41
42	ret = of_address_to_resource(node, 0, &res);
43	of_node_put(node);
44	if (ret)
45		return -EINVAL;
46
47	bcm_smc_buffer = ioremap(res.start, resource_size(&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 */
87static 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 */
118static 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(data->arg3, 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(data->service_id, bcm_smc_buffer_phys);
137}
138
139unsigned 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(0, __bcm_kona_smc, &data, 1);
156
157	return data.result;
158}
159