1 // SPDX-License-Identifier: GPL-2.0+
3 * Copyright (C) 2010 Broadcom
6 #include <linux/init.h>
7 #include <linux/irqchip.h>
9 #include <linux/of_address.h>
10 #include <linux/of_fdt.h>
11 #include <asm/system_info.h>
13 #include <asm/mach/arch.h>
14 #include <asm/mach/map.h>
15 #include <asm/memory.h>
16 #include <asm/pgtable.h>
20 #define BCM2835_USB_VIRT_BASE (VMALLOC_START)
21 #define BCM2835_USB_VIRT_MPHI (VMALLOC_START + 0x10000)
23 static void __init bcm2835_init(void)
25 struct device_node *np = of_find_node_by_path("/system");
29 if (!of_property_read_u32(np, "linux,revision", &val))
31 if (!of_property_read_u64(np, "linux,serial", &val64))
32 system_serial_low = val64;
36 * We need to map registers that are going to be accessed by the FIQ
37 * very early, before any kernel threads are spawned. Because if done
38 * later, the mapping tables are not updated instantly but lazily upon
39 * first access through a data abort handler. While that is fine
40 * when executing regular kernel code, if the first access in a specific
41 * thread happens while running FIQ code this will result in a panic.
43 * For more background see the following old mailing list thread:
44 * https://www.spinics.net/lists/arm-kernel/msg325250.html
46 static int __init bcm2835_map_usb(unsigned long node, const char *uname,
47 int depth, void *data)
49 struct map_desc map[2];
52 unsigned long p2b_offset = *((unsigned long *) data);
54 if (!of_flat_dt_is_compatible(node, "brcm,bcm2708-usb"))
56 reg = of_get_flat_dt_prop(node, "reg", &len);
57 if (!reg || len != (sizeof(unsigned long) * 4))
60 /* Use information about the physical addresses of the
61 * registers from the device tree, but use legacy
62 * iotable_init() static mapping function to map them,
63 * as ioremap() is not functional at this stage in boot.
65 map[0].virtual = (unsigned long) BCM2835_USB_VIRT_BASE;
66 map[0].pfn = __phys_to_pfn(be32_to_cpu(reg[0]) - p2b_offset);
67 map[0].length = be32_to_cpu(reg[1]);
68 map[0].type = MT_DEVICE;
69 map[1].virtual = (unsigned long) BCM2835_USB_VIRT_MPHI;
70 map[1].pfn = __phys_to_pfn(be32_to_cpu(reg[2]) - p2b_offset);
71 map[1].length = be32_to_cpu(reg[3]);
72 map[1].type = MT_DEVICE;
78 static void __init bcm2835_map_io(void)
80 const __be32 *ranges, *address_cells;
81 unsigned long root, addr_cells;
83 unsigned long p2b_offset;
87 root = of_get_flat_dt_root();
88 /* Find out how to map bus to physical address first from soc/ranges */
89 soc = of_get_flat_dt_subnode_by_name(root, "soc");
92 address_cells = of_get_flat_dt_prop(root, "#address-cells", &len);
93 if (!address_cells || len < (sizeof(unsigned long)))
95 addr_cells = be32_to_cpu(address_cells[0]);
96 ranges = of_get_flat_dt_prop(soc, "ranges", &len);
97 if (!ranges || len < (sizeof(unsigned long) * (2 + addr_cells)))
99 p2b_offset = be32_to_cpu(ranges[0]) - be32_to_cpu(ranges[addr_cells]);
101 /* Now search for bcm2708-usb node in device tree */
102 of_scan_flat_dt(bcm2835_map_usb, &p2b_offset);
105 static const char * const bcm2835_compat[] = {
106 #ifdef CONFIG_ARCH_MULTI_V6
109 #ifdef CONFIG_ARCH_MULTI_V7
117 DT_MACHINE_START(BCM2835, "BCM2835")
118 #if defined(CONFIG_ZONE_DMA) && defined(CONFIG_ARM_LPAE)
119 .dma_zone_size = SZ_1G,
121 .map_io = bcm2835_map_io,
122 .init_machine = bcm2835_init,
123 .dt_compat = bcm2835_compat,
124 .smp = smp_ops(bcm2836_smp_ops),