xref: /openbmc/u-boot/arch/arm/cpu/armv7/virt-v7.c (revision 5ff10aa7)
1 /*
2  * (C) Copyright 2013
3  * Andre Przywara, Linaro <andre.przywara@linaro.org>
4  *
5  * Routines to transition ARMv7 processors from secure into non-secure state
6  * and from non-secure SVC into HYP mode
7  * needed to enable ARMv7 virtualization for current hypervisors
8  *
9  * SPDX-License-Identifier:	GPL-2.0+
10  */
11 
12 #include <common.h>
13 #include <asm/armv7.h>
14 #include <asm/gic.h>
15 #include <asm/io.h>
16 #include <asm/secure.h>
17 
18 unsigned long gic_dist_addr;
19 
20 static unsigned int read_id_pfr1(void)
21 {
22 	unsigned int reg;
23 
24 	asm("mrc p15, 0, %0, c0, c1, 1\n" : "=r"(reg));
25 	return reg;
26 }
27 
28 static unsigned long get_gicd_base_address(void)
29 {
30 #ifdef CONFIG_ARM_GIC_BASE_ADDRESS
31 	return CONFIG_ARM_GIC_BASE_ADDRESS + GIC_DIST_OFFSET;
32 #else
33 	unsigned periphbase;
34 
35 	/* get the GIC base address from the CBAR register */
36 	asm("mrc p15, 4, %0, c15, c0, 0\n" : "=r" (periphbase));
37 
38 	/* the PERIPHBASE can be mapped above 4 GB (lower 8 bits used to
39 	 * encode this). Bail out here since we cannot access this without
40 	 * enabling paging.
41 	 */
42 	if ((periphbase & 0xff) != 0) {
43 		printf("nonsec: PERIPHBASE is above 4 GB, no access.\n");
44 		return -1;
45 	}
46 
47 	return (periphbase & CBAR_MASK) + GIC_DIST_OFFSET;
48 #endif
49 }
50 
51 static void relocate_secure_section(void)
52 {
53 #ifdef CONFIG_ARMV7_SECURE_BASE
54 	size_t sz = __secure_end - __secure_start;
55 
56 	memcpy((void *)CONFIG_ARMV7_SECURE_BASE, __secure_start, sz);
57 	flush_dcache_range(CONFIG_ARMV7_SECURE_BASE,
58 			   CONFIG_ARMV7_SECURE_BASE + sz + 1);
59 	invalidate_icache_all();
60 #endif
61 }
62 
63 static void kick_secondary_cpus_gic(unsigned long gicdaddr)
64 {
65 	/* kick all CPUs (except this one) by writing to GICD_SGIR */
66 	writel(1U << 24, gicdaddr + GICD_SGIR);
67 }
68 
69 void __weak smp_kick_all_cpus(void)
70 {
71 	kick_secondary_cpus_gic(gic_dist_addr);
72 }
73 
74 int armv7_init_nonsec(void)
75 {
76 	unsigned int reg;
77 	unsigned itlinesnr, i;
78 
79 	/* check whether the CPU supports the security extensions */
80 	reg = read_id_pfr1();
81 	if ((reg & 0xF0) == 0) {
82 		printf("nonsec: Security extensions not implemented.\n");
83 		return -1;
84 	}
85 
86 	/* the SCR register will be set directly in the monitor mode handler,
87 	 * according to the spec one should not tinker with it in secure state
88 	 * in SVC mode. Do not try to read it once in non-secure state,
89 	 * any access to it will trap.
90 	 */
91 
92 	gic_dist_addr = get_gicd_base_address();
93 	if (gic_dist_addr == -1)
94 		return -1;
95 
96 	/* enable the GIC distributor */
97 	writel(readl(gic_dist_addr + GICD_CTLR) | 0x03,
98 	       gic_dist_addr + GICD_CTLR);
99 
100 	/* TYPER[4:0] contains an encoded number of available interrupts */
101 	itlinesnr = readl(gic_dist_addr + GICD_TYPER) & 0x1f;
102 
103 	/* set all bits in the GIC group registers to one to allow access
104 	 * from non-secure state. The first 32 interrupts are private per
105 	 * CPU and will be set later when enabling the GIC for each core
106 	 */
107 	for (i = 1; i <= itlinesnr; i++)
108 		writel((unsigned)-1, gic_dist_addr + GICD_IGROUPRn + 4 * i);
109 
110 #ifndef CONFIG_ARMV7_PSCI
111 	smp_set_core_boot_addr((unsigned long)secure_ram_addr(_smp_pen), -1);
112 	smp_kick_all_cpus();
113 #endif
114 
115 	/* call the non-sec switching code on this CPU also */
116 	relocate_secure_section();
117 	secure_ram_addr(_nonsec_init)();
118 	return 0;
119 }
120