1/* 2 * c 2001 PPC 64 Team, IBM Corp 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * /dev/nvram driver for PPC 10 * 11 */ 12 13#include <linux/kernel.h> 14#include <linux/init.h> 15#include <linux/spinlock.h> 16#include <asm/uaccess.h> 17#include <asm/prom.h> 18#include <asm/machdep.h> 19#include <asm/rtas.h> 20#include "chrp.h" 21 22static unsigned int nvram_size; 23static unsigned char nvram_buf[4]; 24static DEFINE_SPINLOCK(nvram_lock); 25 26static unsigned char chrp_nvram_read(int addr) 27{ 28 unsigned int done; 29 unsigned long flags; 30 unsigned char ret; 31 32 if (addr >= nvram_size) { 33 printk(KERN_DEBUG "%s: read addr %d > nvram_size %u\n", 34 current->comm, addr, nvram_size); 35 return 0xff; 36 } 37 spin_lock_irqsave(&nvram_lock, flags); 38 if ((rtas_call(rtas_token("nvram-fetch"), 3, 2, &done, addr, 39 __pa(nvram_buf), 1) != 0) || 1 != done) 40 ret = 0xff; 41 else 42 ret = nvram_buf[0]; 43 spin_unlock_irqrestore(&nvram_lock, flags); 44 45 return ret; 46} 47 48static void chrp_nvram_write(int addr, unsigned char val) 49{ 50 unsigned int done; 51 unsigned long flags; 52 53 if (addr >= nvram_size) { 54 printk(KERN_DEBUG "%s: write addr %d > nvram_size %u\n", 55 current->comm, addr, nvram_size); 56 return; 57 } 58 spin_lock_irqsave(&nvram_lock, flags); 59 nvram_buf[0] = val; 60 if ((rtas_call(rtas_token("nvram-store"), 3, 2, &done, addr, 61 __pa(nvram_buf), 1) != 0) || 1 != done) 62 printk(KERN_DEBUG "rtas IO error storing 0x%02x at %d", val, addr); 63 spin_unlock_irqrestore(&nvram_lock, flags); 64} 65 66void __init chrp_nvram_init(void) 67{ 68 struct device_node *nvram; 69 const unsigned int *nbytes_p; 70 unsigned int proplen; 71 72 nvram = of_find_node_by_type(NULL, "nvram"); 73 if (nvram == NULL) 74 return; 75 76 nbytes_p = of_get_property(nvram, "#bytes", &proplen); 77 if (nbytes_p == NULL || proplen != sizeof(unsigned int)) 78 return; 79 80 nvram_size = *nbytes_p; 81 82 printk(KERN_INFO "CHRP nvram contains %u bytes\n", nvram_size); 83 of_node_put(nvram); 84 85 ppc_md.nvram_read_val = chrp_nvram_read; 86 ppc_md.nvram_write_val = chrp_nvram_write; 87 88 return; 89} 90