1628daa8dSBenjamin Herrenschmidt /* 2628daa8dSBenjamin Herrenschmidt * PowerNV nvram code. 3628daa8dSBenjamin Herrenschmidt * 4628daa8dSBenjamin Herrenschmidt * Copyright 2011 IBM Corp. 5628daa8dSBenjamin Herrenschmidt * 6628daa8dSBenjamin Herrenschmidt * This program is free software; you can redistribute it and/or 7628daa8dSBenjamin Herrenschmidt * modify it under the terms of the GNU General Public License 8628daa8dSBenjamin Herrenschmidt * as published by the Free Software Foundation; either version 9628daa8dSBenjamin Herrenschmidt * 2 of the License, or (at your option) any later version. 10628daa8dSBenjamin Herrenschmidt */ 11628daa8dSBenjamin Herrenschmidt 12628daa8dSBenjamin Herrenschmidt #define DEBUG 13628daa8dSBenjamin Herrenschmidt 14628daa8dSBenjamin Herrenschmidt #include <linux/kernel.h> 15628daa8dSBenjamin Herrenschmidt #include <linux/init.h> 16628daa8dSBenjamin Herrenschmidt #include <linux/of.h> 17628daa8dSBenjamin Herrenschmidt 18628daa8dSBenjamin Herrenschmidt #include <asm/opal.h> 19628daa8dSBenjamin Herrenschmidt #include <asm/machdep.h> 20628daa8dSBenjamin Herrenschmidt 21628daa8dSBenjamin Herrenschmidt static unsigned int nvram_size; 22628daa8dSBenjamin Herrenschmidt 23628daa8dSBenjamin Herrenschmidt static ssize_t opal_nvram_size(void) 24628daa8dSBenjamin Herrenschmidt { 25628daa8dSBenjamin Herrenschmidt return nvram_size; 26628daa8dSBenjamin Herrenschmidt } 27628daa8dSBenjamin Herrenschmidt 28628daa8dSBenjamin Herrenschmidt static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index) 29628daa8dSBenjamin Herrenschmidt { 30628daa8dSBenjamin Herrenschmidt s64 rc; 31628daa8dSBenjamin Herrenschmidt int off; 32628daa8dSBenjamin Herrenschmidt 33628daa8dSBenjamin Herrenschmidt if (*index >= nvram_size) 34628daa8dSBenjamin Herrenschmidt return 0; 35628daa8dSBenjamin Herrenschmidt off = *index; 36628daa8dSBenjamin Herrenschmidt if ((off + count) > nvram_size) 37628daa8dSBenjamin Herrenschmidt count = nvram_size - off; 38628daa8dSBenjamin Herrenschmidt rc = opal_read_nvram(__pa(buf), count, off); 39628daa8dSBenjamin Herrenschmidt if (rc != OPAL_SUCCESS) 40628daa8dSBenjamin Herrenschmidt return -EIO; 41628daa8dSBenjamin Herrenschmidt *index += count; 42628daa8dSBenjamin Herrenschmidt return count; 43628daa8dSBenjamin Herrenschmidt } 44628daa8dSBenjamin Herrenschmidt 45628daa8dSBenjamin Herrenschmidt static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) 46628daa8dSBenjamin Herrenschmidt { 47628daa8dSBenjamin Herrenschmidt s64 rc = OPAL_BUSY; 48628daa8dSBenjamin Herrenschmidt int off; 49628daa8dSBenjamin Herrenschmidt 50628daa8dSBenjamin Herrenschmidt if (*index >= nvram_size) 51628daa8dSBenjamin Herrenschmidt return 0; 52628daa8dSBenjamin Herrenschmidt off = *index; 53628daa8dSBenjamin Herrenschmidt if ((off + count) > nvram_size) 54628daa8dSBenjamin Herrenschmidt count = nvram_size - off; 55628daa8dSBenjamin Herrenschmidt 56628daa8dSBenjamin Herrenschmidt while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { 57628daa8dSBenjamin Herrenschmidt rc = opal_write_nvram(__pa(buf), count, off); 58628daa8dSBenjamin Herrenschmidt if (rc == OPAL_BUSY_EVENT) 59628daa8dSBenjamin Herrenschmidt opal_poll_events(NULL); 60628daa8dSBenjamin Herrenschmidt } 61628daa8dSBenjamin Herrenschmidt *index += count; 62628daa8dSBenjamin Herrenschmidt return count; 63628daa8dSBenjamin Herrenschmidt } 64628daa8dSBenjamin Herrenschmidt 65628daa8dSBenjamin Herrenschmidt void __init opal_nvram_init(void) 66628daa8dSBenjamin Herrenschmidt { 67628daa8dSBenjamin Herrenschmidt struct device_node *np; 6881063cddSBenjamin Herrenschmidt const __be32 *nbytes_p; 69628daa8dSBenjamin Herrenschmidt 70628daa8dSBenjamin Herrenschmidt np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram"); 71628daa8dSBenjamin Herrenschmidt if (np == NULL) 72628daa8dSBenjamin Herrenschmidt return; 73628daa8dSBenjamin Herrenschmidt 74628daa8dSBenjamin Herrenschmidt nbytes_p = of_get_property(np, "#bytes", NULL); 75628daa8dSBenjamin Herrenschmidt if (!nbytes_p) { 76628daa8dSBenjamin Herrenschmidt of_node_put(np); 77628daa8dSBenjamin Herrenschmidt return; 78628daa8dSBenjamin Herrenschmidt } 7981063cddSBenjamin Herrenschmidt nvram_size = be32_to_cpup(nbytes_p); 80628daa8dSBenjamin Herrenschmidt 81628daa8dSBenjamin Herrenschmidt printk(KERN_INFO "OPAL nvram setup, %u bytes\n", nvram_size); 82628daa8dSBenjamin Herrenschmidt of_node_put(np); 83628daa8dSBenjamin Herrenschmidt 84628daa8dSBenjamin Herrenschmidt ppc_md.nvram_read = opal_nvram_read; 85628daa8dSBenjamin Herrenschmidt ppc_md.nvram_write = opal_nvram_write; 86628daa8dSBenjamin Herrenschmidt ppc_md.nvram_size = opal_nvram_size; 87628daa8dSBenjamin Herrenschmidt } 88628daa8dSBenjamin Herrenschmidt 89