coreboot-kgpe-d16/src/arch/x86/ebda.c

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/* SPDX-License-Identifier: GPL-2.0-only */
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
#include <stdint.h>
#include <acpi/acpi.h>
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
#include <arch/ebda.h>
#include <commonlib/endian.h>
#include <console/console.h>
static void *get_ebda_start(void)
{
return (void *)((uintptr_t)DEFAULT_EBDA_SEGMENT << 4);
}
/*
* EBDA area is representing a 1KB memory area just below
* the top of conventional memory (below 1MB)
*/
static void setup_ebda(u32 low_memory_size, u16 ebda_segment, u16 ebda_size)
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
{
u16 low_memory_kb;
u16 ebda_kb;
void *ebda;
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
if (!low_memory_size || !ebda_segment || !ebda_size)
return;
low_memory_kb = low_memory_size >> 10;
ebda_kb = ebda_size >> 10;
ebda = get_ebda_start();
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
/* clear BIOS DATA AREA */
zero_n(X86_BDA_BASE, X86_BDA_SIZE);
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
/* Avoid unaligned write16() since it's undefined behavior */
write_le16(X86_EBDA_LOWMEM, low_memory_kb);
write_le16(X86_EBDA_SEGMENT, ebda_segment);
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
/* Set up EBDA */
zero_n(ebda, ebda_size);
write_le16(ebda, ebda_kb);
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
}
void setup_default_ebda(void)
{
if (acpi_is_wakeup_s3())
return;
Prepare the BIOS data areas before device init. Since we do not run option roms in normal mode nothing was initializing the BDA/EBDA and yet Linux depends very much on it having sane values here. For the most part the kernel tries to work around this not being initialized, but every once in awhile (1/300 boots or so) it would end up reading something that looked sane from BDA but was not and then it would panic. In this change the EBDA is unconditionally setup before devices are initialized. I'm not set on the location in dev_initialize() but there does not seem to be another place to hook it in so that it runs just once for ALL platforms regardless of whether they use option roms or not. (possibly hardwaremain?) The EBDA setup code has been moved into its own location in arch/x86/lib/ebda.c so it can be compiled in even if the option rom code is not. The low memory size is still set to 1MB which is enough to make linux happy without having to hook into each mainboard to get a more appropriate value. The setup_ebda() function takes inputs so it could be changed for a mainboard if needed. OLD/BROKEN would read garbage. Examples from different boots: ebda_addr=0x75e80 lowmem=0x1553400 ebda_addr=0x5e080 lowmem=0x3e51400 ebda_addr=0x7aa80 lowmem=0x2f8a800 NEW/FIXED now reads consistent values: ebda_addr=0xf6000 lowmem=0x100000 Change-Id: I6cb79f0e3e43cc65f7e5fe98b6cad1a557ccd949 Signed-off-by: Duncan Laurie <dlaurie@google.com> Reviewed-on: http://review.coreboot.org/769 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
2012-01-17 18:03:11 +01:00
setup_ebda(DEFAULT_EBDA_LOWMEM,
DEFAULT_EBDA_SEGMENT,
DEFAULT_EBDA_SIZE);
}