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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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149 lines
3.1 KiB
C
149 lines
3.1 KiB
C
/*
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* c 2001 PPC 64 Team, IBM Corp
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* /dev/nvram driver for PPC64
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*
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* This perhaps should live in drivers/char
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*/
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <asm/uaccess.h>
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#include <asm/nvram.h>
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#include <asm/rtas.h>
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#include <asm/prom.h>
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#include <asm/machdep.h>
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static unsigned int nvram_size;
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static int nvram_fetch, nvram_store;
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static char nvram_buf[NVRW_CNT]; /* assume this is in the first 4GB */
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static DEFINE_SPINLOCK(nvram_lock);
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static ssize_t pSeries_nvram_read(char *buf, size_t count, loff_t *index)
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{
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unsigned int i;
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unsigned long len;
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int done;
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unsigned long flags;
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char *p = buf;
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if (nvram_size == 0 || nvram_fetch == RTAS_UNKNOWN_SERVICE)
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return -ENODEV;
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if (*index >= nvram_size)
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return 0;
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i = *index;
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if (i + count > nvram_size)
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count = nvram_size - i;
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spin_lock_irqsave(&nvram_lock, flags);
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for (; count != 0; count -= len) {
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len = count;
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if (len > NVRW_CNT)
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len = NVRW_CNT;
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if ((rtas_call(nvram_fetch, 3, 2, &done, i, __pa(nvram_buf),
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len) != 0) || len != done) {
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spin_unlock_irqrestore(&nvram_lock, flags);
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return -EIO;
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}
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memcpy(p, nvram_buf, len);
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p += len;
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i += len;
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}
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spin_unlock_irqrestore(&nvram_lock, flags);
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*index = i;
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return p - buf;
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}
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static ssize_t pSeries_nvram_write(char *buf, size_t count, loff_t *index)
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{
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unsigned int i;
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unsigned long len;
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int done;
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unsigned long flags;
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const char *p = buf;
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if (nvram_size == 0 || nvram_store == RTAS_UNKNOWN_SERVICE)
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return -ENODEV;
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if (*index >= nvram_size)
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return 0;
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i = *index;
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if (i + count > nvram_size)
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count = nvram_size - i;
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spin_lock_irqsave(&nvram_lock, flags);
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for (; count != 0; count -= len) {
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len = count;
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if (len > NVRW_CNT)
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len = NVRW_CNT;
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memcpy(nvram_buf, p, len);
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if ((rtas_call(nvram_store, 3, 2, &done, i, __pa(nvram_buf),
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len) != 0) || len != done) {
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spin_unlock_irqrestore(&nvram_lock, flags);
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return -EIO;
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}
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p += len;
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i += len;
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}
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spin_unlock_irqrestore(&nvram_lock, flags);
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*index = i;
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return p - buf;
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}
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static ssize_t pSeries_nvram_get_size(void)
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{
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return nvram_size ? nvram_size : -ENODEV;
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}
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int __init pSeries_nvram_init(void)
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{
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struct device_node *nvram;
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unsigned int *nbytes_p, proplen;
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nvram = of_find_node_by_type(NULL, "nvram");
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if (nvram == NULL)
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return -ENODEV;
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nbytes_p = (unsigned int *)get_property(nvram, "#bytes", &proplen);
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if (nbytes_p == NULL || proplen != sizeof(unsigned int))
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return -EIO;
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nvram_size = *nbytes_p;
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nvram_fetch = rtas_token("nvram-fetch");
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nvram_store = rtas_token("nvram-store");
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printk(KERN_INFO "PPC64 nvram contains %d bytes\n", nvram_size);
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of_node_put(nvram);
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ppc_md.nvram_read = pSeries_nvram_read;
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ppc_md.nvram_write = pSeries_nvram_write;
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ppc_md.nvram_size = pSeries_nvram_get_size;
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return 0;
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}
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