xref: /openbmc/linux/arch/mips/bcm47xx/prom.c (revision 9470114d)
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/memblock.h>
31 #include <linux/spinlock.h>
32 #include <linux/ssb/ssb_driver_chipcommon.h>
33 #include <linux/ssb/ssb_regs.h>
34 #include <linux/smp.h>
35 #include <asm/bootinfo.h>
36 #include <bcm47xx.h>
37 #include <bcm47xx_board.h>
38 
39 static char bcm47xx_system_type[20] = "Broadcom BCM47XX";
40 
41 const char *get_system_type(void)
42 {
43 	return bcm47xx_system_type;
44 }
45 
46 __init void bcm47xx_set_system_type(u16 chip_id)
47 {
48 	snprintf(bcm47xx_system_type, sizeof(bcm47xx_system_type),
49 		 (chip_id > 0x9999) ? "Broadcom BCM%d" :
50 				      "Broadcom BCM%04X",
51 		 chip_id);
52 }
53 
54 static unsigned long lowmem __initdata;
55 
56 static __init void prom_init_mem(void)
57 {
58 	unsigned long mem;
59 	unsigned long max;
60 	unsigned long off;
61 	struct cpuinfo_mips *c = &current_cpu_data;
62 
63 	/* Figure out memory size by finding aliases.
64 	 *
65 	 * We should theoretically use the mapping from CFE using cfe_enummem().
66 	 * However as the BCM47XX is mostly used on low-memory systems, we
67 	 * want to reuse the memory used by CFE (around 4MB). That means cfe_*
68 	 * functions stop to work at some point during the boot, we should only
69 	 * call them at the beginning of the boot.
70 	 *
71 	 * BCM47XX uses 128MB for addressing the ram, if the system contains
72 	 * less than that amount of ram it remaps the ram more often into the
73 	 * available space.
74 	 */
75 
76 	/* Physical address, without mapping to any kernel segment */
77 	off = CPHYSADDR((unsigned long)prom_init);
78 
79 	/* Accessing memory after 128 MiB will cause an exception */
80 	max = 128 << 20;
81 
82 	for (mem = 1 << 20; mem < max; mem += 1 << 20) {
83 		/* Loop condition may be not enough, off may be over 1 MiB */
84 		if (off + mem >= max) {
85 			mem = max;
86 			pr_debug("Assume 128MB RAM\n");
87 			break;
88 		}
89 		if (!memcmp((void *)prom_init, (void *)prom_init + mem, 32))
90 			break;
91 	}
92 	lowmem = mem;
93 
94 	/* Ignoring the last page when ddr size is 128M. Cached
95 	 * accesses to last page is causing the processor to prefetch
96 	 * using address above 128M stepping out of the ddr address
97 	 * space.
98 	 */
99 	if (c->cputype == CPU_74K && (mem == (128  << 20)))
100 		mem -= 0x1000;
101 	memblock_add(0, mem);
102 }
103 
104 /*
105  * This is the first serial on the chip common core, it is at this position
106  * for sb (ssb) and ai (bcma) bus.
107  */
108 #define BCM47XX_SERIAL_ADDR (SSB_ENUM_BASE + SSB_CHIPCO_UART0_DATA)
109 
110 void __init prom_init(void)
111 {
112 	prom_init_mem();
113 	setup_8250_early_printk_port(CKSEG1ADDR(BCM47XX_SERIAL_ADDR), 0, 0);
114 }
115 
116 #if defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM)
117 
118 #define EXTVBASE	0xc0000000
119 #define ENTRYLO(x)	((pte_val(pfn_pte((x) >> PFN_PTE_SHIFT, PAGE_KERNEL_UNCACHED)) >> 6) | 1)
120 
121 #include <asm/tlbflush.h>
122 
123 /* Stripped version of tlb_init, with the call to build_tlb_refill_handler
124  * dropped. Calling it at this stage causes a hang.
125  */
126 void early_tlb_init(void)
127 {
128 	write_c0_pagemask(PM_DEFAULT_MASK);
129 	write_c0_wired(0);
130 	temp_tlb_entry = current_cpu_data.tlbsize - 1;
131 	local_flush_tlb_all();
132 }
133 
134 void __init bcm47xx_prom_highmem_init(void)
135 {
136 	unsigned long off = (unsigned long)prom_init;
137 	unsigned long extmem = 0;
138 	bool highmem_region = false;
139 
140 	if (WARN_ON(bcm47xx_bus_type != BCM47XX_BUS_TYPE_BCMA))
141 		return;
142 
143 	if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
144 		highmem_region = true;
145 
146 	if (lowmem != 128 << 20 || !highmem_region)
147 		return;
148 
149 	early_tlb_init();
150 
151 	/* Add one temporary TLB entry to map SDRAM Region 2.
152 	 *      Physical        Virtual
153 	 *      0x80000000      0xc0000000      (1st: 256MB)
154 	 *      0x90000000      0xd0000000      (2nd: 256MB)
155 	 */
156 	add_temporary_entry(ENTRYLO(0x80000000),
157 			    ENTRYLO(0x80000000 + (256 << 20)),
158 			    EXTVBASE, PM_256M);
159 
160 	off = EXTVBASE + __pa(off);
161 	for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) {
162 		if (!memcmp((void *)prom_init, (void *)(off + extmem), 16))
163 			break;
164 	}
165 	extmem -= lowmem;
166 
167 	early_tlb_init();
168 
169 	if (!extmem)
170 		return;
171 
172 	pr_warn("Found %lu MiB of extra memory, but highmem is unsupported yet!\n",
173 		extmem >> 20);
174 
175 	/* TODO: Register extra memory */
176 }
177 
178 #endif /* defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM) */
179