xref: /openbmc/linux/arch/mips/bcm47xx/prom.c (revision d2168146)
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 
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 __init void prom_init_mem(void)
55 {
56 	unsigned long mem;
57 	unsigned long max;
58 	unsigned long off;
59 	struct cpuinfo_mips *c = &current_cpu_data;
60 
61 	/* Figure out memory size by finding aliases.
62 	 *
63 	 * We should theoretically use the mapping from CFE using cfe_enummem().
64 	 * However as the BCM47XX is mostly used on low-memory systems, we
65 	 * want to reuse the memory used by CFE (around 4MB). That means cfe_*
66 	 * functions stop to work at some point during the boot, we should only
67 	 * call them at the beginning of the boot.
68 	 *
69 	 * BCM47XX uses 128MB for addressing the ram, if the system contains
70 	 * less that that amount of ram it remaps the ram more often into the
71 	 * available space.
72 	 */
73 
74 	/* Physical address, without mapping to any kernel segment */
75 	off = CPHYSADDR((unsigned long)prom_init);
76 
77 	/* Accessing memory after 128 MiB will cause an exception */
78 	max = 128 << 20;
79 
80 	for (mem = 1 << 20; mem < max; mem += 1 << 20) {
81 		/* Loop condition may be not enough, off may be over 1 MiB */
82 		if (off + mem >= max) {
83 			mem = max;
84 			printk(KERN_DEBUG "assume 128MB RAM\n");
85 			break;
86 		}
87 		if (!memcmp(prom_init, prom_init + mem, 32))
88 			break;
89 	}
90 
91 	/* Ignoring the last page when ddr size is 128M. Cached
92 	 * accesses to last page is causing the processor to prefetch
93 	 * using address above 128M stepping out of the ddr address
94 	 * space.
95 	 */
96 	if (c->cputype == CPU_74K && (mem == (128  << 20)))
97 		mem -= 0x1000;
98 
99 	add_memory_region(0, mem, BOOT_MEM_RAM);
100 }
101 
102 /*
103  * This is the first serial on the chip common core, it is at this position
104  * for sb (ssb) and ai (bcma) bus.
105  */
106 #define BCM47XX_SERIAL_ADDR (SSB_ENUM_BASE + SSB_CHIPCO_UART0_DATA)
107 
108 void __init prom_init(void)
109 {
110 	prom_init_mem();
111 	setup_8250_early_printk_port(CKSEG1ADDR(BCM47XX_SERIAL_ADDR), 0, 0);
112 }
113 
114 void __init prom_free_prom_memory(void)
115 {
116 }
117