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 #ifdef CONFIG_PPC64_BOOT_WRAPPER
  17
  18 /* Global OPAL struct used by opal-call.S */
  19 struct opal {
  20         u64 base;
  21         u64 entry;
  22 } opal;
  23
  24 static u32 opal_con_id;
  25
  26 /* see opal-wrappers.S */
  27 int64_t opal_console_write(int64_t term_number, u64 *length, const u8 *buffer);
  28 int64_t opal_console_read(int64_t term_number, uint64_t *length, u8 *buffer);
  29 int64_t opal_console_write_buffer_space(uint64_t term_number, uint64_t *length);
  30 int64_t opal_console_flush(uint64_t term_number);
  31 int64_t opal_poll_events(uint64_t *outstanding_event_mask);
  32
  33 void opal_kentry(unsigned long fdt_addr, void *vmlinux_addr);
  34
  35 static int opal_con_open(void)
  36 {
  37         /*
  38          * When OPAL loads the boot kernel it stashes the OPAL base and entry
  39          * address in r8 and r9 so the kernel can use the OPAL console
  40          * before unflattening the devicetree. While executing the wrapper will
  41          * probably trash r8 and r9 so this kentry hook restores them before
  42          * entering the decompressed kernel.
  43          */
  44         platform_ops.kentry = opal_kentry;
  45         return 0;
  46 }
  47
  48 static void opal_con_putc(unsigned char c)
  49 {
  50         int64_t rc;
  51         uint64_t olen, len;
  52
  53         do {
  54                 rc = opal_console_write_buffer_space(opal_con_id, &olen);
  55                 len = be64_to_cpu(olen);
  56                 if (rc)
  57                         return;
  58                 opal_poll_events(NULL);
  59         } while (len < 1);
  60
  61
  62         olen = cpu_to_be64(1);
  63         opal_console_write(opal_con_id, &olen, &c);
  64 }
  65
  66 static void opal_con_close(void)
  67 {
  68         opal_console_flush(opal_con_id);
  69 }
  70
  71 static void opal_init(void)
  72 {
  73         void *opal_node;
  74
  75         opal_node = finddevice("/ibm,opal");
  76         if (!opal_node)
  77                 return;
  78         if (getprop(opal_node, "opal-base-address", &opal.base, sizeof(u64)) < 0)
  79                 return;
  80         opal.base = be64_to_cpu(opal.base);
  81         if (getprop(opal_node, "opal-entry-address", &opal.entry, sizeof(u64)) < 0)
  82                 return;
  83         opal.entry = be64_to_cpu(opal.entry);
  84 }
  85
  86 int opal_console_init(void *devp, struct serial_console_data *scdp)
  87 {
  88         opal_init();
  89
  90         if (devp) {
  91                 int n = getprop(devp, "reg", &opal_con_id, sizeof(u32));
  92                 if (n != sizeof(u32))
  93                         return -1;
  94                 opal_con_id = be32_to_cpu(opal_con_id);
  95         } else
  96                 opal_con_id = 0;
  97
  98         scdp->open = opal_con_open;
  99         scdp->putc = opal_con_putc;
 100         scdp->close = opal_con_close;
 101
 102         return 0;
 103 }
 104 #else
 105 int opal_console_init(void *devp, struct serial_console_data *scdp)
 106 {
 107         return -1;
 108 }
 109 #endif /* __powerpc64__ */