xref: /openbmc/linux/arch/mips/bcm47xx/prom.c (revision 94cdda6b)
1 /*
2  *  Copyright (C) 2004 Florian Schirmer <jolt@tuxbox.org>
3  *  Copyright (C) 2007 Aurelien Jarno <aurelien@aurel32.net>
4  *  Copyright (C) 2010-2012 Hauke Mehrtens <hauke@hauke-m.de>
5  *
6  *  This program is free software; you can redistribute  it and/or modify it
7  *  under  the terms of  the GNU General  Public License as published by the
8  *  Free Software Foundation;  either version 2 of the  License, or (at your
9  *  option) any later version.
10  *
11  *  THIS  SOFTWARE  IS PROVIDED   ``AS  IS'' AND   ANY  EXPRESS OR IMPLIED
12  *  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
13  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
14  *  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT, INDIRECT,
15  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
16  *  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
17  *  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
18  *  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
19  *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
20  *  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
21  *
22  *  You should have received a copy of the  GNU General Public License along
23  *  with this program; if not, write  to the Free Software Foundation, Inc.,
24  *  675 Mass Ave, Cambridge, MA 02139, USA.
25  */
26 
27 #include <linux/init.h>
28 #include <linux/types.h>
29 #include <linux/kernel.h>
30 #include <linux/spinlock.h>
31 #include <linux/ssb/ssb_driver_chipcommon.h>
32 #include <linux/ssb/ssb_regs.h>
33 #include <linux/smp.h>
34 #include <asm/bootinfo.h>
35 #include <bcm47xx.h>
36 #include <bcm47xx_board.h>
37 
38 static char bcm47xx_system_type[20] = "Broadcom BCM47XX";
39 
40 const char *get_system_type(void)
41 {
42 	return bcm47xx_system_type;
43 }
44 
45 __init void bcm47xx_set_system_type(u16 chip_id)
46 {
47 	snprintf(bcm47xx_system_type, sizeof(bcm47xx_system_type),
48 		 (chip_id > 0x9999) ? "Broadcom BCM%d" :
49 				      "Broadcom BCM%04X",
50 		 chip_id);
51 }
52 
53 static unsigned long lowmem __initdata;
54 
55 static __init void prom_init_mem(void)
56 {
57 	unsigned long mem;
58 	unsigned long max;
59 	unsigned long off;
60 	struct cpuinfo_mips *c = &current_cpu_data;
61 
62 	/* Figure out memory size by finding aliases.
63 	 *
64 	 * We should theoretically use the mapping from CFE using cfe_enummem().
65 	 * However as the BCM47XX is mostly used on low-memory systems, we
66 	 * want to reuse the memory used by CFE (around 4MB). That means cfe_*
67 	 * functions stop to work at some point during the boot, we should only
68 	 * call them at the beginning of the boot.
69 	 *
70 	 * BCM47XX uses 128MB for addressing the ram, if the system contains
71 	 * less that that amount of ram it remaps the ram more often into the
72 	 * available space.
73 	 */
74 
75 	/* Physical address, without mapping to any kernel segment */
76 	off = CPHYSADDR((unsigned long)prom_init);
77 
78 	/* Accessing memory after 128 MiB will cause an exception */
79 	max = 128 << 20;
80 
81 	for (mem = 1 << 20; mem < max; mem += 1 << 20) {
82 		/* Loop condition may be not enough, off may be over 1 MiB */
83 		if (off + mem >= max) {
84 			mem = max;
85 			pr_debug("Assume 128MB RAM\n");
86 			break;
87 		}
88 		if (!memcmp(prom_init, prom_init + mem, 32))
89 			break;
90 	}
91 	lowmem = mem;
92 
93 	/* Ignoring the last page when ddr size is 128M. Cached
94 	 * accesses to last page is causing the processor to prefetch
95 	 * using address above 128M stepping out of the ddr address
96 	 * space.
97 	 */
98 	if (c->cputype == CPU_74K && (mem == (128  << 20)))
99 		mem -= 0x1000;
100 	add_memory_region(0, mem, BOOT_MEM_RAM);
101 }
102 
103 /*
104  * This is the first serial on the chip common core, it is at this position
105  * for sb (ssb) and ai (bcma) bus.
106  */
107 #define BCM47XX_SERIAL_ADDR (SSB_ENUM_BASE + SSB_CHIPCO_UART0_DATA)
108 
109 void __init prom_init(void)
110 {
111 	prom_init_mem();
112 	setup_8250_early_printk_port(CKSEG1ADDR(BCM47XX_SERIAL_ADDR), 0, 0);
113 }
114 
115 void __init prom_free_prom_memory(void)
116 {
117 }
118 
119 #if defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM)
120 
121 #define EXTVBASE	0xc0000000
122 #define ENTRYLO(x)	((pte_val(pfn_pte((x) >> _PFN_SHIFT, PAGE_KERNEL_UNCACHED)) >> 6) | 1)
123 
124 #include <asm/tlbflush.h>
125 
126 /* Stripped version of tlb_init, with the call to build_tlb_refill_handler
127  * dropped. Calling it at this stage causes a hang.
128  */
129 void __cpuinit early_tlb_init(void)
130 {
131 	write_c0_pagemask(PM_DEFAULT_MASK);
132 	write_c0_wired(0);
133 	temp_tlb_entry = current_cpu_data.tlbsize - 1;
134 	local_flush_tlb_all();
135 }
136 
137 void __init bcm47xx_prom_highmem_init(void)
138 {
139 	unsigned long off = (unsigned long)prom_init;
140 	unsigned long extmem = 0;
141 	bool highmem_region = false;
142 
143 	if (WARN_ON(bcm47xx_bus_type != BCM47XX_BUS_TYPE_BCMA))
144 		return;
145 
146 	if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
147 		highmem_region = true;
148 
149 	if (lowmem != 128 << 20 || !highmem_region)
150 		return;
151 
152 	early_tlb_init();
153 
154 	/* Add one temporary TLB entry to map SDRAM Region 2.
155 	 *      Physical        Virtual
156 	 *      0x80000000      0xc0000000      (1st: 256MB)
157 	 *      0x90000000      0xd0000000      (2nd: 256MB)
158 	 */
159 	add_temporary_entry(ENTRYLO(0x80000000),
160 			    ENTRYLO(0x80000000 + (256 << 20)),
161 			    EXTVBASE, PM_256M);
162 
163 	off = EXTVBASE + __pa(off);
164 	for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) {
165 		if (!memcmp(prom_init, (void *)(off + extmem), 16))
166 			break;
167 	}
168 	extmem -= lowmem;
169 
170 	early_tlb_init();
171 
172 	if (!extmem)
173 		return;
174 
175 	pr_warn("Found %lu MiB of extra memory, but highmem is unsupported yet!\n",
176 		extmem >> 20);
177 
178 	/* TODO: Register extra memory */
179 }
180 
181 #endif /* defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM) */
182