1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PowerNV nvram code. 4 * 5 * Copyright 2011 IBM Corp. 6 */ 7 8 #define DEBUG 9 10 #include <linux/delay.h> 11 #include <linux/kernel.h> 12 #include <linux/init.h> 13 #include <linux/of.h> 14 15 #include <asm/opal.h> 16 #include <asm/nvram.h> 17 #include <asm/machdep.h> 18 19 static unsigned int nvram_size; 20 21 static ssize_t opal_nvram_size(void) 22 { 23 return nvram_size; 24 } 25 26 static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index) 27 { 28 s64 rc; 29 int off; 30 31 if (*index >= nvram_size) 32 return 0; 33 off = *index; 34 if ((off + count) > nvram_size) 35 count = nvram_size - off; 36 rc = opal_read_nvram(__pa(buf), count, off); 37 if (rc != OPAL_SUCCESS) 38 return -EIO; 39 *index += count; 40 return count; 41 } 42 43 /* 44 * This can be called in the panic path with interrupts off, so use 45 * mdelay in that case. 46 */ 47 static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) 48 { 49 s64 rc = OPAL_BUSY; 50 int off; 51 52 if (*index >= nvram_size) 53 return 0; 54 off = *index; 55 if ((off + count) > nvram_size) 56 count = nvram_size - off; 57 58 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { 59 rc = opal_write_nvram(__pa(buf), count, off); 60 if (rc == OPAL_BUSY_EVENT) { 61 if (in_interrupt() || irqs_disabled()) 62 mdelay(OPAL_BUSY_DELAY_MS); 63 else 64 msleep(OPAL_BUSY_DELAY_MS); 65 opal_poll_events(NULL); 66 } else if (rc == OPAL_BUSY) { 67 if (in_interrupt() || irqs_disabled()) 68 mdelay(OPAL_BUSY_DELAY_MS); 69 else 70 msleep(OPAL_BUSY_DELAY_MS); 71 } 72 } 73 74 if (rc) 75 return -EIO; 76 77 *index += count; 78 return count; 79 } 80 81 static int __init opal_nvram_init_log_partitions(void) 82 { 83 /* Scan nvram for partitions */ 84 nvram_scan_partitions(); 85 nvram_init_oops_partition(0); 86 return 0; 87 } 88 machine_arch_initcall(powernv, opal_nvram_init_log_partitions); 89 90 void __init opal_nvram_init(void) 91 { 92 struct device_node *np; 93 const __be32 *nbytes_p; 94 95 np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram"); 96 if (np == NULL) 97 return; 98 99 nbytes_p = of_get_property(np, "#bytes", NULL); 100 if (!nbytes_p) { 101 of_node_put(np); 102 return; 103 } 104 nvram_size = be32_to_cpup(nbytes_p); 105 106 pr_info("OPAL nvram setup, %u bytes\n", nvram_size); 107 of_node_put(np); 108 109 ppc_md.nvram_read = opal_nvram_read; 110 ppc_md.nvram_write = opal_nvram_write; 111 ppc_md.nvram_size = opal_nvram_size; 112 } 113 114