bcm_kona_smc.c

  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}