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Update the design doc to match a mixture of wishful thinking and
reality. * We use LAR and not CPIO * printk() can be called from stage 1 without ill effects * stage 2 phase 1 is without purpose Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net> Acked-by: Ronald G. Minnich <rminnich@gmail.com> git-svn-id: svn://coreboot.org/repository/LinuxBIOSv3@511 f3766cd6-281f-0410-b1cd-43a5c92072e9
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Carl-Daniel Hailfinger
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09f99f998d
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3de758e98a
1 changed files with 82 additions and 27 deletions
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@ -85,7 +85,7 @@ That is, "1." instead of just "1"
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\begin_layout Standard
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The new LinuxBIOS boot architecture depends on CAR, with payloads appearing
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as files in a CPIO archive.
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as files in a LAR archive.
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The device tree is defined by a device tree blob (DTB) and all the activities
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flow from that.
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For now, the DTC will produce a standard LinuxBIOS v2 device tree; this
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@ -150,7 +150,7 @@ Shown in
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is the layout of the whole FLASH.
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Note that we can kill the buildrom tool, since the FLASH code is now a
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CPIO archive.
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LAR archive.
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Note that the linker script will now be very simple.
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The initram is roughly what is in auto.c, although the early hardware setup
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from auto.c is now in the pre-initram, so that we have serial output and
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@ -162,7 +162,7 @@ Shown in
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etc.
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The DTB can be modified by the flashrom tool, and hence a platform can
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be customized from a binary FLASH image.
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Each CPIO file has a checksum attached to the end, so that the system can
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Each LAR file has a checksum attached to the end, so that the system can
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verify that the data is uncorrupted.
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We now build at least four targets for a platform:
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\end_layout
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@ -290,9 +290,9 @@ subtractive address ranges
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\emph default
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, which define an address range that is picked up by default if no other
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resource claims it.
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\emph on
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Subtractive address ranges
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Subtractive address ranges
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\emph default
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are typically used for legacy PC address ranges.
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@ -734,7 +734,7 @@ CAR is a standard cache-as-ram assembly source for the architecture.
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It is actually included in the stage0_*.S file; but we maintain a distinction
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in the stage nomenclature for now.
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This code sets up cache-as-ram, zeros a memory area, sets up a stack, and
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then calls Stage 1.
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then calls stage 1.
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\end_layout
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@ -758,13 +758,53 @@ CONFIG_ROMSIZE.
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Stage 1: C, in arch/{architecture}
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\end_layout
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\begin_layout Standard
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Initial entry point for stage 1 is arch/{architecture}/stage1.c:stage1_main().
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\end_layout
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\begin_layout Standard
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printk() may be used from anywhere in C code, but it will output characters
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only after the welcome banner has been printed.
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\end_layout
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\begin_layout Enumerate
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Preboot hardware, as from auto.c (C)
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POST(0x02).
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(C)
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\end_layout
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\begin_layout Enumerate
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Stop secondary processors.
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(C)
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\end_layout
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\begin_layout Enumerate
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Preboot hardware, as from auto.c (C).
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hardware_stage1()
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\end_layout
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\begin_layout Enumerate
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Initialize serial port.
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(C)
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\end_layout
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\begin_layout Enumerate
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Initialize USB debug port.
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(C)
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\end_layout
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\begin_layout Enumerate
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Print welcome banner to celebrate working printk() output.
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(C)
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\end_layout
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\begin_layout Enumerate
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Enable ROM.
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(C)
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\end_layout
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\begin_layout Enumerate
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Decide whether we can proceed or must recover from serial port.
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(C)
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Criteria? (C)
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\end_layout
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\begin_layout Enumerate
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@ -778,7 +818,7 @@ boot area
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, if it is bad then ...
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recover from serial port (C, PIC).
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We can definitely reflash CPIO archive, but NOTE: reflashing the boot block
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We can definitely reflash LAR archive, but NOTE: reflashing the boot block
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is tricky ...
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(C)
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\end_layout
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@ -791,13 +831,36 @@ Examine the flash.
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\begin_inset Quotes eld
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\end_inset
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fallback', etc.) (C)
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fallback', etc.).
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(C)
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\end_layout
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\begin_layout Enumerate
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In that directory, need 'initram', 'payload.ext', and others.
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make sure that in '/', there is a decompressor of the right type for each
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extension needed.
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In that directory, execute 'initram'.
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If that fails, execute 'initram' in any other directory.
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If that fails as well, recover from serial port.
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(C, PIC)
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\end_layout
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\begin_layout Enumerate
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Make sure that in '/', there is a decompressor for each compression type
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used.
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(C)
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\end_layout
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\begin_layout Enumerate
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In the directory named by the boot type, execute 'stage2'.
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(C)
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\end_layout
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\begin_layout Enumerate
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In that directory, look for a file 'payload', and load all of 'payload/segment%d
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'.
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(C)
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\end_layout
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\begin_layout Enumerate
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Jump to the entry point of 'payload/segment0'.
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(C)
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\end_layout
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@ -834,13 +897,11 @@ The second is a simple traversal, via linked list, of all the devices.
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\end_layout
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\begin_layout Subparagraph*
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Phase 1 -- making printk work
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Phase 1 -- very early setup
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\end_layout
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\begin_layout Standard
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These are any functions that are required to make printk operational.
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No other code should be run in Phase 1.
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This phase existed to make printk work and has been obsoleted.
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\end_layout
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\begin_layout Standard
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@ -867,8 +928,6 @@ Phase 2 -- preparation for bus scan
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\begin_layout Standard
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These are functions that are required before any PCI operations of any kind
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are run.
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These functions may call printk.
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\end_layout
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\begin_layout Standard
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@ -1650,9 +1709,9 @@ struct superio superio {
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\begin_layout Standard
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In our opinion, this is asking for trouble.
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We currently, in the superio code, can catch stupid errors in usage that
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would be lost were we to go to this
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would be lost were we to go to this
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\family sans
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void * based approach.
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void * based approach.
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In fact, we can argue that we ought to be adding stronger type checking
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to the tree, not taking it away.
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As of this version of the document, the handling of the superio is not
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@ -2445,9 +2504,9 @@ The errors were mainly changes to printk.
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This file is only used for the southbridge part, so, following LinuxBIOS
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include rules, cs5536.h does not go in include; rather, it goes in the
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\family typewriter
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southbridge/amd/cs5536
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southbridge/amd/cs5536
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\family default
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directory.
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directory.
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We fix the includes so that they have proper names, and add Doxygen comments,
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which as of June 1, 2007, are required for all commits.
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Also, all functions save smbus_read_byte are static, as only that one function
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@ -2473,10 +2532,6 @@ We bring across the cs5536_early_setup.c, and make the few changes needed
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\end_layout
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\begin_layout Standard
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\end_layout
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\begin_layout Standard
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Now it is time to fix the compilation errors.
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First, we need to get the pll_reset.c function from V2.
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