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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/README.gpt | 201 | ||||
| -rw-r--r-- | doc/README.silent | 14 | ||||
| -rw-r--r-- | doc/device-tree-bindings/pwm/tegra20-pwm.txt | 18 | ||||
| -rw-r--r-- | doc/device-tree-bindings/video/displaymode.txt | 42 | ||||
| -rw-r--r-- | doc/device-tree-bindings/video/tegra20-dc.txt | 85 |
5 files changed, 356 insertions, 4 deletions
diff --git a/doc/README.gpt b/doc/README.gpt new file mode 100644 index 00000000000..a9c58b4c966 --- /dev/null +++ b/doc/README.gpt @@ -0,0 +1,201 @@ +# +# Copyright (C) 2012 Samsung Electronics +# +# Lukasz Majewski <l.majewski@samsung.com> +# +# +# See file CREDITS for list of people who contributed to this +# project. +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License as +# published by the Free Software Foundation; either version 2 of +# the License, or (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, +# MA 02111-1307 USA + + +Glossary: +======== +- UUID -(Universally Unique Identifier) +- GUID - (Globally Unique ID) +- EFI - (Extensible Firmware Interface) +- UEFI - (Unified EFI) - EFI evolution +- GPT (GUID Partition Table) - it is the EFI standard part +- partitions - lists of available partitions (defined at u-boot): + ./include/configs/{target}.h + +Introduction: +============= +This document describes the GPT partition table format and usage of +the gpt command in u-boot. + + +UUID introduction: +==================== + +GPT for marking disks/partitions is using the UUID. It is supposed to be a +globally unique value. A UUID is a 16-byte (128-bit) number. The number of +theoretically possible UUIDs is therefore about 3 x 10^38. +More often UUID is displayed as 32 hexadecimal digits, in 5 groups, +separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters +(32 digits and 4 hyphens) + +For instance, GUID of Linux data partition: EBD0A0A2-B9E5-4433-87C0-68B6B72699C7 + +Historically there are 5 methods to generate this number. The oldest one is +combining machine's MAC address and timer (epoch) value. + +Successive versions are using MD5 hash, random numbers and SHA-1 hash. All major +OSes and programming languages are providing libraries to compute UUID (e.g. +uuid command line tool). + +GPT brief explanation: +====================== + + Layout: + ------- + + -------------------------------------------------- + LBA 0 |Protective MBR | + ---------------------------------------------------------- + LBA 1 |Primary GPT Header | Primary + -------------------------------------------------- GPT + LBA 2 |Entry 1|Entry 2| Entry 3| Entry 4| + -------------------------------------------------- + LBA 3 |Entries 5 - 128 | + | | + | | + ---------------------------------------------------------- + LBA 34 |Partition 1 | + | | + ----------------------------------- + |Partition 2 | + | | + ----------------------------------- + |Partition n | + | | + ---------------------------------------------------------- + LBA -34 |Entry 1|Entry 2| Entry 3| Entry 4| Secondary + -------------------------------------------------- (bkp) + LBA -33 |Entries 5 - 128 | GPT + | | + | | + LBA -2 | | + -------------------------------------------------- + LBA -1 |Secondary GPT Header | + ---------------------------------------------------------- + + +For a legacy reasons, GPT's LBA 0 sector has a MBR structure. It is called +"protective MBR". +Its first partition entry ID has 0xEE value, and disk software, which is not +handling the GPT sees it as a storage device without free space. + +It is possible to define 128 linearly placed partition entries. + +"LBA -1" means the last addressable block (in the mmc subsystem: +"dev_desc->lba - 1") + +Primary/Secondary GPT header: +---------------------------- +Offset Size Description + +0 8 B Signature ("EFI PART", 45 46 49 20 50 41 52 54) +8 4 B Revision (For version 1.0, the value is 00 00 01 00) +12 4 B Header size (in bytes, usually 5C 00 00 00 meaning 92 bytes) +16 4 B CRC32 of header (0 to header size), with this field zeroed + during calculation +20 4 B Reserved (ZERO); +24 8 B Current LBA (location of this header copy) +32 8 B Backup LBA (location of the other header copy) +40 8 B First usable LBA for partitions (primary partition table last + LBA + 1) +48 8 B Last usable LBA (secondary partition table first LBA - 1) +56 16 B Disk GUID (also referred as UUID on UNIXes) +72 8 B Partition entries starting LBA (always 2 in primary copy) +80 4 B Number of partition entries +84 4 B Size of a partition entry (usually 128) +88 4 B CRC32 of partition array +92 * Reserved; must be ZERO (420 bytes for a 512-byte LBA) + +TOTAL: 512 B + + + +IMPORTANT: + +GPT headers and partition entries are protected by CRC32 (the POSIX CRC32). + +Primary GPT header and Secondary GPT header have swapped values of "Current LBA" +and "Backup LBA" and therefore different CRC32 check-sum. + +CRC32 for GPT headers (field "CRC of header") are calculated up till +"Header size" (92), NOT 512 bytes. + +CRC32 for partition entries (field "CRC32 of partition array") is calculated for +the whole array entry ( Number_of_partition_entries * +sizeof(partition_entry_size (usually 128))) + +Observe, how Secondary GPT is placed in the memory. It is NOT a mirror reflect +of the Primary. + + + Partition Entry Format: + ---------------------- + Offset Size Description + + 0 16 B Partition type GUID + 16 16 B Unique partition GUID + 32 8 B First LBA (Little Endian) + 40 8 B Last LBA (inclusive) + 48 8 B Attribute flags [+] + 56 72 B Partition name (text) + + Attribute flags: + Bit 0 - System partition + Bit 60 - Read-only + Bit 62 - Hidden + Bit 63 - Not mount + + +Creating GPT partitions in U-Boot: +============== + +To restore GUID partition table one needs to: +1. Define partition layout in the environment. + Format of partitions layout: + "partitions=uuid_disk=...;name=u-boot,size=60MiB,uuid=...; + name=kernel,size=60MiB,uuid=...;" + or + "partitions=uuid_disk=${uuid_gpt_disk};name=${uboot_name}, + size=${uboot_size},uuid=${uboot_uuid};" + + Fields 'name', 'size' and 'uuid' are mandatory for every partition. + The field 'start' is optional. + +2. Define 'CONFIG_EFI_PARTITION' and 'CONFIG_CMD_GPT' + +2. From u-boot prompt type: + gpt write mmc 0 $partitions + + +Useful info: +============ + +Two programs, namely: 'fdisk' and 'parted' are recommended to work with GPT +recovery. Parted is able to handle GUID partitions. Unfortunately the 'fdisk' +hasn't got such ability. +Please, pay attention at -l switch for parted. + +"uuid" program is recommended to generate UUID string. Moreover it can decode +(-d switch) passed in UUID string. It can be used to generate partitions UUID +passed to u-boot environment variables. diff --git a/doc/README.silent b/doc/README.silent index a26e3df0da6..70202cece97 100644 --- a/doc/README.silent +++ b/doc/README.silent @@ -1,9 +1,15 @@ The config option CONFIG_SILENT_CONSOLE can be used to quiet messages on the console. If the option has been enabled, the output can be -silenced by setting the environment variable "silent". The variable -is latched into the global data at an early stage in the boot process -so deleting it with "setenv" will not take effect until the system is -restarted. +silenced by setting the environment variable "silent". + +- CONFIG_SILENT_CONSOLE_UPDATE_ON_SET + When the "silent" variable is changed with env set, the change + will take effect immediately. + +- CONFIG_SILENT_CONSOLE_UPDATE_ON_RELOC + Some environments are not available until relocation (e.g. NAND) + so this will make the value in the flash env take effect at + relocation. The following actions are taken if "silent" is set at boot time: diff --git a/doc/device-tree-bindings/pwm/tegra20-pwm.txt b/doc/device-tree-bindings/pwm/tegra20-pwm.txt new file mode 100644 index 00000000000..01438ecd662 --- /dev/null +++ b/doc/device-tree-bindings/pwm/tegra20-pwm.txt @@ -0,0 +1,18 @@ +Tegra SoC PWFM controller + +Required properties: +- compatible: should be one of: + - "nvidia,tegra20-pwm" + - "nvidia,tegra30-pwm" +- reg: physical base address and length of the controller's registers +- #pwm-cells: On Tegra the number of cells used to specify a PWM is 2. The + first cell specifies the per-chip index of the PWM to use and the second + cell is the period in nanoseconds. + +Example: + + pwm: pwm@7000a000 { + compatible = "nvidia,tegra20-pwm"; + reg = <0x7000a000 0x100>; + #pwm-cells = <2>; + }; diff --git a/doc/device-tree-bindings/video/displaymode.txt b/doc/device-tree-bindings/video/displaymode.txt new file mode 100644 index 00000000000..45ca42db508 --- /dev/null +++ b/doc/device-tree-bindings/video/displaymode.txt @@ -0,0 +1,42 @@ +videomode bindings +================== + +(from http://lists.freedesktop.org/archives/dri-devel/2012-July/024875.html) + +Required properties: + - xres, yres: Display resolution + - left-margin, right-margin, hsync-len: Horizontal Display timing + parameters in pixels + - upper-margin, lower-margin, vsync-len: Vertical display timing + parameters in lines + - clock: display clock in Hz + +Optional properties: + - width-mm, height-mm: Display dimensions in mm + - hsync-active-high (bool): Hsync pulse is active high + - vsync-active-high (bool): Vsync pulse is active high + - interlaced (bool): This is an interlaced mode + - doublescan (bool): This is a doublescan mode + +There are different ways of describing a display mode. The devicetree +representation corresponds to the one used by the Linux Framebuffer +framework described here in Documentation/fb/framebuffer.txt. This +representation has been chosen because it's the only format which does +not allow for inconsistent parameters. Unlike the Framebuffer framework +the devicetree has the clock in Hz instead of ps. + +Example: + + display@0 { + /* 1920x1080p24 */ + clock = <52000000>; + xres = <1920>; + yres = <1080>; + left-margin = <25>; + right-margin = <25>; + hsync-len = <25>; + lower-margin = <2>; + upper-margin = <2>; + vsync-len = <2>; + hsync-active-high; + }; diff --git a/doc/device-tree-bindings/video/tegra20-dc.txt b/doc/device-tree-bindings/video/tegra20-dc.txt new file mode 100644 index 00000000000..4731c3fbab4 --- /dev/null +++ b/doc/device-tree-bindings/video/tegra20-dc.txt @@ -0,0 +1,85 @@ +Display Controller +------------------ + +(there isn't yet a generic binding in Linux, so this describes what is in +U-Boot, and may change based on Linux activity) + +The device node for a display device is as described in the document +"Open Firmware Recommended Practice : Universal Serial Bus" with the +following modifications and additions : + +Required properties : + - compatible : Should be "nvidia,tegra20-dc" + +Required subnode 'rgb' is as follows: + +Required properties (rgb) : + - nvidia,panel : phandle of LCD panel information + + +The panel node describes the panel itself. This has the properties listed in +displaymode.txt as well as: + +Required properties (panel) : + - nvidia,bits-per-pixel: number of bits per pixel (depth) + - nvidia,pwm : pwm to use to set display contrast (see tegra20-pwm.txt) + - nvidia,panel-timings: 4 cells containing required timings in ms: + * delay before asserting panel_vdd + * delay between panel_vdd-rise and data-rise + * delay between data-rise and backlight_vdd-rise + * delay between backlight_vdd and pwm-rise + * delay between pwm-rise and backlight_en-rise + +Optional GPIO properies all have (phandle, GPIO number, flags): + - nvidia,backlight-enable-gpios: backlight enable GPIO + - nvidia,lvds-shutdown-gpios: LVDS power shutdown GPIO + - nvidia,backlight-vdd-gpios: backlight power GPIO + - nvidia,panel-vdd-gpios: panel power GPIO + +Example: + +host1x { + compatible = "nvidia,tegra20-host1x", "simple-bus"; + reg = <0x50000000 0x00024000>; + interrupts = <0 65 0x04 /* mpcore syncpt */ + 0 67 0x04>; /* mpcore general */ + + #address-cells = <1>; + #size-cells = <1>; + status = "okay"; + + ranges = <0x54000000 0x54000000 0x04000000>; + + dc@54200000 { + compatible = "nvidia,tegra20-dc"; + reg = <0x54200000 0x00040000>; + interrupts = <0 73 0x04>; + status = "okay"; + + rgb { + status = "okay"; + nvidia,panel = <&lcd_panel>; + }; + }; +}; + +lcd_panel: panel { + /* Seaboard has 1366x768 */ + clock = <70600000>; + xres = <1366>; + yres = <768>; + left-margin = <58>; + right-margin = <58>; + hsync-len = <58>; + lower-margin = <4>; + upper-margin = <4>; + vsync-len = <4>; + hsync-active-high; + nvidia,bits-per-pixel = <16>; + nvidia,pwm = <&pwm 2 0>; + nvidia,backlight-enable-gpios = <&gpio 28 0>; /* PD4 */ + nvidia,lvds-shutdown-gpios = <&gpio 10 0>; /* PB2 */ + nvidia,backlight-vdd-gpios = <&gpio 176 0>; /* PW0 */ + nvidia,panel-vdd-gpios = <&gpio 22 0>; /* PC6 */ + nvidia,panel-timings = <400 4 203 17 15>; +}; |