965c7ecaf2
Impact: remove unused/broken code The Voyager subarch last built successfully on the v2.6.26 kernel and has been stale since then and does not build on the v2.6.27, v2.6.28 and v2.6.29-rc5 kernels. No actual users beyond the maintainer reported this breakage. Patches were sent and most of the fixes were accepted but the discussion around how to do a few remaining issues cleanly fizzled out with no resolution and the code remained broken. In the v2.6.30 x86 tree development cycle 32-bit subarch support has been reworked and removed - and the Voyager code, beyond the build problems already known, needs serious and significant changes and probably a rewrite to support it. CONFIG_X86_VOYAGER has been marked BROKEN then. The maintainer has been notified but no patches have been sent so far to fix it. While all other subarchs have been converted to the new scheme, voyager is still broken. We'd prefer to receive patches which clean up the current situation in a constructive way, but even in case of removal there is no obstacle to add that support back after the issues have been sorted out in a mutually acceptable fashion. So remove this inactive code for now. Signed-off-by: Ingo Molnar <mingo@elte.hu>
163 lines
3.4 KiB
C
163 lines
3.4 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright 2007-2008 rPath, Inc. - All Rights Reserved
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* Copyright 2009 Intel Corporation
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*
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* This file is part of the Linux kernel, and is made available under
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* the terms of the GNU General Public License version 2.
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*
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* ----------------------------------------------------------------------- */
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/*
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* Enable A20 gate (return -1 on failure)
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*/
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#include "boot.h"
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#define MAX_8042_LOOPS 100000
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#define MAX_8042_FF 32
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static int empty_8042(void)
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{
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u8 status;
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int loops = MAX_8042_LOOPS;
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int ffs = MAX_8042_FF;
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while (loops--) {
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io_delay();
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status = inb(0x64);
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if (status == 0xff) {
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/* FF is a plausible, but very unlikely status */
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if (!--ffs)
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return -1; /* Assume no KBC present */
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}
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if (status & 1) {
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/* Read and discard input data */
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io_delay();
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(void)inb(0x60);
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} else if (!(status & 2)) {
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/* Buffers empty, finished! */
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return 0;
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}
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}
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return -1;
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}
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/* Returns nonzero if the A20 line is enabled. The memory address
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used as a test is the int $0x80 vector, which should be safe. */
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#define A20_TEST_ADDR (4*0x80)
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#define A20_TEST_SHORT 32
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#define A20_TEST_LONG 2097152 /* 2^21 */
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static int a20_test(int loops)
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{
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int ok = 0;
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int saved, ctr;
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set_fs(0x0000);
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set_gs(0xffff);
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saved = ctr = rdfs32(A20_TEST_ADDR);
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while (loops--) {
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wrfs32(++ctr, A20_TEST_ADDR);
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io_delay(); /* Serialize and make delay constant */
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ok = rdgs32(A20_TEST_ADDR+0x10) ^ ctr;
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if (ok)
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break;
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}
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wrfs32(saved, A20_TEST_ADDR);
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return ok;
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}
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/* Quick test to see if A20 is already enabled */
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static int a20_test_short(void)
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{
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return a20_test(A20_TEST_SHORT);
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}
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/* Longer test that actually waits for A20 to come on line; this
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is useful when dealing with the KBC or other slow external circuitry. */
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static int a20_test_long(void)
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{
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return a20_test(A20_TEST_LONG);
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}
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static void enable_a20_bios(void)
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{
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asm volatile("pushfl; int $0x15; popfl"
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: : "a" ((u16)0x2401));
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}
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static void enable_a20_kbc(void)
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{
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empty_8042();
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outb(0xd1, 0x64); /* Command write */
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empty_8042();
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outb(0xdf, 0x60); /* A20 on */
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empty_8042();
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outb(0xff, 0x64); /* Null command, but UHCI wants it */
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empty_8042();
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}
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static void enable_a20_fast(void)
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{
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u8 port_a;
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port_a = inb(0x92); /* Configuration port A */
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port_a |= 0x02; /* Enable A20 */
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port_a &= ~0x01; /* Do not reset machine */
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outb(port_a, 0x92);
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}
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/*
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* Actual routine to enable A20; return 0 on ok, -1 on failure
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*/
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#define A20_ENABLE_LOOPS 255 /* Number of times to try */
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int enable_a20(void)
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{
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int loops = A20_ENABLE_LOOPS;
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int kbc_err;
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while (loops--) {
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/* First, check to see if A20 is already enabled
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(legacy free, etc.) */
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if (a20_test_short())
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return 0;
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/* Next, try the BIOS (INT 0x15, AX=0x2401) */
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enable_a20_bios();
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if (a20_test_short())
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return 0;
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/* Try enabling A20 through the keyboard controller */
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kbc_err = empty_8042();
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if (a20_test_short())
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return 0; /* BIOS worked, but with delayed reaction */
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if (!kbc_err) {
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enable_a20_kbc();
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if (a20_test_long())
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return 0;
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}
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/* Finally, try enabling the "fast A20 gate" */
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enable_a20_fast();
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if (a20_test_long())
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return 0;
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}
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return -1;
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}
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