arch/powerpc/boot/opal.c

   1 /*
   2  * Copyright (c) 2016 IBM Corporation.
   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
  10 #include "ops.h"
  11 #include "stdio.h"
  12 #include "io.h"
  13 #include <libfdt.h>
  14 #include "../include/asm/opal-api.h"
  15
  16 /* Global OPAL struct used by opal-call.S */
  17 struct opal {
  18         u64 base;
  19         u64 entry;
  20 } opal;
  21
  22 static u32 opal_con_id;
  23
  24 /* see opal-wrappers.S */
  25 int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
  26 int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
  27 int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
  28 int64_t opal_console_flush(uint64_t term_number);
  29 int64_t opal_poll_events(uint64_t *outstanding_event_mask);
  30
  31 void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
  32
  33 static int opal_con_open(void)
  34 {
  35         /*
  36          * When OPAL loads the boot kernel it stashes the OPAL base and entry
  37          * address in r8 and r9 so the kernel can use the OPAL console
  38          * before unflattening the devicetree. While executing the wrapper will
  39          * probably trash r8 and r9 so this kentry hook restores them before
  40          * entering the decompressed kernel.
  41          */
  42         platform_ops.kentry = opal_kentry;
  43         return 0;
  44 }
  45
  46 static void opal_con_putc(unsigned char c)
  47 {
  48         int64_t rc;
  49         uint64_t olen, len;
  50
  51         do {
  52                 rc = opal_console_write_buffer_space(opal_con_id, &olen);
  53                 len = be64_to_cpu(olen);
  54                 if (rc)
  55                         return;
  56                 opal_poll_events(NULL);
  57         } while (len < 1);
  58
  59
  60         olen = cpu_to_be64(1);
  61         opal_console_write(opal_con_id, &olen, &c);
  62 }
  63
  64 static void opal_con_close(void)
  65 {
  66         opal_console_flush(opal_con_id);
  67 }
  68
  69 static void opal_init(void)
  70 {
  71         void *opal_node;
  72
  73         opal_node = finddevice("/ibm,opal");
  74         if (!opal_node)
  75                 return;
  76         if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
  77                 return;
  78         opal.base = be64_to_cpu(opal.base);
  79         if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
  80                 return;
  81         opal.entry = be64_to_cpu(opal.entry);
  82 }
  83
  84 int opal_console_init(void *devp, struct serial_console_data *scdp)
  85 {
  86         opal_init();
  87
  88         if (devp) {
  89                 int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
  90                 if (n != sizeof(u32))
  91                         return -1;
  92                 opal_con_id = be32_to_cpu(opal_con_id);
  93         } else
  94                 opal_con_id = 0;
  95
  96         scdp->open = opal_con_open;
  97         scdp->putc = opal_con_putc;
  98         scdp->close = opal_con_close;
  99
 100         return 0;
 101 }