karo: tx6: prevent DTB from either being out of reach of kernel or overwritten during...

[karo-tx-uboot.git] / doc / README.x86

diff --git a/doc/README.x86 b/doc/README.x86
index af2459c7ed6af55d989f2902bbf8ec4646975aaa..3bab5cf64e62902240a705e32aa3290205cd596f 100644 (file)
--- a/doc/README.x86
+++ b/doc/README.x86
@@ -18,15 +18,16 @@ U-Boot supports running as a coreboot [1] payload on x86. So far only Link
 work with minimal adjustments on other x86 boards since coreboot deals with
 most of the low-level details.
 
-U-Boot also supports booting directly from x86 reset vector without coreboot,
-aka raw support or bare support. Currently Link, QEMU x86 targets and all
-Intel boards support running U-Boot 'bare metal'.
+U-Boot also supports booting directly from x86 reset vector, without coreboot.
+In this case, known as bare mode, from the fact that it runs on the
+'bare metal', U-Boot acts like a BIOS replacement. Currently Link, QEMU x86
+targets and all Intel boards support running U-Boot 'bare metal'.
 
 As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit
 Linux kernel as part of a FIT image. It also supports a compressed zImage.
 
-Build Instructions
-------------------
+Build Instructions for U-Boot as coreboot payload
+-------------------------------------------------
 Building U-Boot as a coreboot payload is just like building U-Boot for targets
 on other architectures, like below:
 
@@ -48,6 +49,8 @@ Change the 'Board configuration file' and 'Board Device Tree Source (dts) file'
 to point to a new board. You can also change the Cache-As-RAM (CAR) related
 settings here if the default values do not fit your new board.
 
+Build Instructions for U-Boot as BIOS replacement (bare mode)
+-------------------------------------------------------------
 Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a
 little bit tricky, as generally it requires several binary blobs which are not
 shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is
@@ -58,7 +61,9 @@ $ export BUILD_ROM=y
 
 This tells the Makefile to build u-boot.rom as a target.
 
-Link-specific instructions:
+---
+
+Chromebook Link specific instructions for bare mode:
 
 First, you need the following binary blobs:
 
@@ -87,7 +92,9 @@ Now you can build U-Boot and obtain u-boot.rom:
 $ make chromebook_link_defconfig
 $ make all
 
-Intel Crown Bay specific instructions:
+---
+
+Intel Crown Bay specific instructions for bare mode:
 
 U-Boot support of Intel Crown Bay board [4] relies on a binary blob called
 Firmware Support Package [5] to perform all the necessary initialization steps
@@ -122,7 +129,9 @@ Now you can build U-Boot and obtain u-boot.rom
 $ make crownbay_defconfig
 $ make all
 
-Intel Minnowboard Max instructions:
+---
+
+Intel Minnowboard Max instructions for bare mode:
 
 This uses as FSP as with Crown Bay, except it is for the Atom E3800 series.
 Download this and get the .fd file (BAYTRAIL_FSP_GOLD_003_16-SEP-2014.fd at
@@ -188,8 +197,9 @@ Offset   Description         Controlling config
 
 Overall ROM image size is controlled by CONFIG_ROM_SIZE.
 
+---
 
-Intel Galileo instructions:
+Intel Galileo instructions for bare mode:
 
 Only one binary blob is needed for Remote Management Unit (RMU) within Intel
 Quark SoC. Not like FSP, U-Boot does not call into the binary. The binary is
@@ -235,10 +245,10 @@ this capability yet. The command is as follows:
 
 # in the coreboot root directory
 $ ./build/util/cbfstool/cbfstool build/coreboot.rom add-flat-binary \
-  -f u-boot-dtb.bin -n fallback/payload -c lzma -l 0x1110000 -e 0x1110015
+  -f u-boot-dtb.bin -n fallback/payload -c lzma -l 0x1110000 -e 0x1110000
 
-Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE and 0x1110015 matches the
-symbol address of _start (in arch/x86/cpu/start.S).
+Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE, which is the symbol address
+of _x86boot_start (in arch/x86/cpu/start.S).
 
 If you want to use ELF as the coreboot payload, change U-Boot configuration to
 use CONFIG_OF_EMBED instead of CONFIG_OF_SEPARATE.
@@ -252,8 +262,8 @@ At present it seems that for Minnowboard Max, coreboot does not pass through
 the video information correctly (it always says the resolution is 0x0). This
 works correctly for link though.
 
-Test with QEMU
---------------
+Test with QEMU for bare mode
+----------------------------
 QEMU is a fancy emulator that can enable us to test U-Boot without access to
 a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
 U-Boot. To launch QEMU with u-boot.rom, call QEMU as follows:
@@ -644,13 +654,13 @@ Use the device tree for configuration where possible.
 For the microcode you can create a suitable device tree file using the
 microcode tool:
 
-  ./tools/microcode-tool -d microcode.dat create <model>
+  ./tools/microcode-tool -d microcode.dat -m <model> create
 
 or if you only have header files and not the full Intel microcode.dat database:
 
   ./tools/microcode-tool -H BAY_TRAIL_FSP_KIT/Microcode/M0130673322.h \
        -H BAY_TRAIL_FSP_KIT/Microcode/M0130679901.h \
-       create all
+       -m all create
 
 These are written to arch/x86/dts/microcode/ by default.
 
@@ -708,6 +718,21 @@ allocation and assignment will be done by U-Boot automatically. Now you can
 enable CONFIG_GENERATE_PIRQ_TABLE for testing Linux kernel using i8259 PIC and
 CONFIG_GENERATE_MP_TABLE for testing Linux kernel using local APIC and I/O APIC.
 
+This script might be useful. If you feed it the output of 'pci long' from
+U-Boot then it will generate a device tree fragment with the interrupt
+configuration for each device (note it needs gawk 4.0.0):
+
+   $ cat console_output |awk '/PCI/ {device=$4} /interrupt line/ {line=$4} \
+       /interrupt pin/ {pin = $4; if (pin != "0x00" && pin != "0xff") \
+       {patsplit(device, bdf, "[0-9a-f]+"); \
+       printf "PCI_BDF(%d, %d, %d) INT%c PIRQ%c\n", strtonum("0x" bdf[1]), \
+       strtonum("0x" bdf[2]), bdf[3], strtonum(pin) + 64, 64 + strtonum(pin)}}'
+
+Example output:
+   PCI_BDF(0, 2, 0) INTA PIRQA
+   PCI_BDF(0, 3, 0) INTA PIRQA
+...
+
 TODO List
 ---------
 - Audio