Kernel

General

The Kernel on the GTA01 is based on a vanilla 2.6.17.7 Linux kernel from kernel.org.

Some additional patches are required for

S3C2410 Usb Device Controller
- We use the driver from iPaq H1409 linux project
S3C2410 SD Card Controller
- We use the driver from the TomTom GO kernel
QT2410 machine support
- This is just some glue that puts all pieces together
S3C2410 touch screen driver
- Again from iPaq H1409 linux project
GTA01 machine support
- Some glue/configuration to pull all pieces together
GSM Communication Infrastructure
- The kernel-level part (TS07.10 line discipline, GPRS line discipline)

Kernel Patchset

The latest patchset against the abovementioned vanilla kernel can be found at [1]. This is a so-called "quilt patchset". In order to apply it, you have to untar it into a "patches" directory below the "linux-2.6.x" directory, and then call "quilt push -a", which pushes all patches onto the kernel.

Kernel Configuration

The latest kernel configuration can be found at [2]. Just copy it to the linux-2.6.x/.config file.

Kernel building

The kernel build is executed as normal. We actually only need the "vmlinux" target, not the "zImage".

bootable Kernel image

A bootable kernel image called uImage is available from [3]

creating a bootable kernel image

u-boot needs all images (such as kernel, initrd, ...) in the form of an uImage. This is basically just a special header adding CRC protection, version information, etc. Pleaes see u-boot for details.

Kernel Boot Parameters

The kernel image (once http://people.gta01.hmw-consulting.de/laforge/tmp/qt2410-biglcd.patch is integrated) has a new boot parameter "tft".

If you boot without any tft= parameter, the 'stock' qt2410 240x320 TFT panel is assumed.

If you boot with "tft=b" ('b' for big), the timings for the SHARP 640x480 TFT panel are used.

Kernel Subsystems

In this section we will outline a couple of the GTA01 specific kernel drivers / features / subsystems

Asound driver

high-level requirements

The GTA01 audio subsystem is fairly simple, therefore the high-level requirements for the sound driver are simple, too. The features we need to support

voice call support
- passing through the microphone signal to the GSM Modem
- passing through the GSM Modem audio output to the integrated speaker(s)
- the microphone input mixer gain will be statically configured according to the dynamic requirements
- the audio volume that is sent to the GSM modem can be adjusted via line out level
- the audio volume incoming (from GSM modem -> codec) can be adjusted via speaker out level
voice call recording support
- the user is able to record phone conversations on digital storage inside the phone. Format will be ogg (not important to driver)
- ideally, the user can choose between recording only incoming or outgoing signal, or both.
- for both, we'd need to mix both microphone and line-in signals before recording. is this possible?
voice call playback support
- the user is able to playback recorded files during a conversation. this means that PCM playback needs to be mixed with mic input before being passed to line-out (and to the GSM modem)
media playback support
- an audio player can play back mp3/ogg/flac/... files and output sound via integrated speakers or headphone
headphone jack switch
- this is connected to a GPIO of the S3C2410. How to best integrate this with the sound driver? It should just be handled like any other headphone jack reporting of e.g. laptop computers.

implementation

The asound driver will be using the Alsa SoC layer (http://www.rpsys.net/openzaurus/patches/alsa/info.html).

Asoc provides us with

modular interface to various codecs (e.g. easy migration to different codecs)
advanced power-management and power-saving features
orthogonal integration of our machine specific volume control (audio amplifier)

Since Asoc is currently lacking both a S3C2410 platform driver and a WM8976 codec driver, we will need to implement both. The codec driver is expected to be easy, since WM8971 and WM8974 are already supported, and the changes are expected to be not too big.

At the time of this writing, asoc-v0.12 (http://www.rpsys.net/openzaurus/patches/alsa/asoc-v0.12.patch) is current. It was written against a 2.6.17 kernel and therefore matches perfectly with our GTA01 kernel.

Bluetooth

We're using the stock bluez implementation of the linux kernel.

Power Management

The bluetooth basically has the following preconditions

BT_EN being set
The Voltage regulator set up properly
The ohci-hcd driver being loaded

The gta01_pm_bt driver implements the following files:

root@fic-gta01:/$ ls -l /sys/devices/platform/gta01-pm-bt.0
-rw-r--r--    1 root     root         4096 Feb  1 09:52 power_on
-rw-r--r--    1 root     root         4096 Feb  1 09:52 reset

Powering up the device

root@fic-gta01:/$ echo "1" >  /sys/devices/platform/gta01-pm-bt.0/power_on  
usb 1-1: new full speed USB device using s3c2410-ohci and address 4
usb 1-1: configuration #1 chosen from 1 choice

Powering down the device

root@fic-gta01:/$ echo "0" >  /sys/devices/platform/gta01-pm-bt.0/power_on 
usb 1-1: USB disconnect, address 3

Asserting reset (low-active)

root@fic-gta01:/$ echo "0" >  /sys/devices/platform/gta01-pm-bt.0/reset 
root@fic-gta01:/$ usb 1-1: USB disconnect, address 2

De-asserting reset (low-active)

root@fic-gta01:/$ echo "1" >  /sys/devices/platform/gta01-pm-bt.0/reset 
s3c2410-ohci s3c2410-ohci: wakeup
usb 1-1: new full speed USB device using s3c2410-ohci and address 3
usb 1-1: configuration #1 chosen from 1 choice

Getting started

root@fic-gta01:~$ hciconfig hci0 up
root@fic-gta01:~$ hcitool  scan
Scanning ...
        00:14:9A:77:A2:02       A780
root@fic-gta01:~$ hcitool inq 00:14:9A:77:A2:02 
Inquiring ...
        00:14:9A:77:A2:02       clock offset: 0x55df    class: 0x502204
root@fic-gta01:~$ hcitool cc 00:14:9A:77:A2:02 
root@fic-gta01:~$ hcitool con                 
Connections:
        < ACL 00:14:9A:77:A2:02 handle 42 state 1 lm MASTER 
root@fic-gta01:~$ hcitool info 00:14:9A:77:A2:02
Requesting information ...
        BD Address:  00:14:9A:77:A2:02
        Device Name: A780
        LMP Version: 1.1 (0x1) LMP Subversion: 0x700
        Manufacturer: Broadcom Corporation (15)
        Features: 0xff 0xff 0x0d 0x00 0x00 0x00 0x00 0x00
                <3-slot packets> <5-slot packets> <encryption> <slot offset> 
                <timing accuracy> <role switch> <hold mode> <sniff mode> 
                <park state> <RSSI> <channel quality> <SCO link> <HV2 packets> 
                <HV3 packets> <u-law log> <A-law log> <CVSD> <power control> 
                <transparent SCO>

911 Button

The 911 button is supported via the "gta01kbd" driver in the kernel (drivers/input/keyboard/gta01kbd.c).

It creates an input event device that only issues "KEY_PHONE" press/unpress events.

Power Management Unit (PMU)

The PMU is supported via the "pcf50606" driver in the kernel (drivers/i2c/chips/pcf50606.c).

This driver provides a number of userspace interfaces for the various bits and pieces of the PMU

Power Button, Charger insertion

The PMU creates an input device that supports the following keys:

KEY_POWER: power button of GTA01
KEY_POWER2: USB power supply insert/remove
KEY_BATTERY: Charger insert/remove

RTC

The real-time clock, including the alarm feature, is implemented as standard RTC (/dev/rtc).

Watchdog

The PMU-integrated watchdog is implemented using the standard watchdog character device.

Voltage Regulators

The voltage regulators are exported to userspace using sysfs, much like lm_sensors.

Every regulator can be read (and written!). The format is ASCII in millivolts.

root@fic-gta01:/sys/devices/platform/s3c2410-i2c/i2c-0/0-0008$ ls -l /sys/bus/i2c/devices/0-0008/voltage_*
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_d1reg
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_d2reg
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_d3reg
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_dcd
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_dcde
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_dcud
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_lpreg
-rw-r--r--    1 root     root         4096 Sep  3 11:55 /sys/bus/i2c/devices/0-0008/voltage_ioreg
root@fic-gta01:/sys/devices/platform/s3c2410-i2c/i2c-0/0-0008$ cat voltage_dcd
1300

Battery Voltage

The battery voltage (in millivolts) can be read via sysfs

root@fic-gta01:~$ cat /sys/bus/i2c/devices/0-0008/battvolt 
3767

Battery charging current

The battery charging current (in milliamperes) can be read via sysfs

root@fic-gta01:~$ cat /sys/bus/i2c/devices/0-0008/chgcur 
0

Battery temperature

The battery temperature (in centigrades) can be read via sysfs

root@fic-gta01:~$ cat /sys/bus/i2c/devices/0-0008/battemp
25

Kernel TODO

Various

use bigger font as default
speed up in-kernel boot process
- delay calibration
- sd-card driver as module
- framebuffer takes ages
check GPIO initialization with regard to GTA01v4 changes

TS07.10 multiplex

PCF50606

fix conversion problems when setting alarm time/date
add conversion chart for temperature, once battery type NTC data sheet is known
- who is supposed to have that datasheet?
add some intelligent shutdown handler when POWER key is pressed for more then 3/5 seconds (input device KEY_POWER?)
test battery charging
implement 'persistent alarm setting' (see mail from mickey)

backlight

rather than only on/off support, use PWM for backlight levels
later: implement smooth fade-in, fade-out

vibrator

implement it as LED driver
test it once prototype with case is available
later: implement PWM

USB device driver

make sure usb-net works stable with GTA01v4
test switching between usb host and usb device

Sound

waiting for S3C2410 host asoc support by Wolfson

Power Management

test, debug and fix suspend on user request
test, debug and fix wakeup on
- IRQ on serial UART (GSM)
- IRQ on serial UART (GPS)
- IRQ from PMU (charger insert/remove or the like)
- IRQ from ADC/touchscreen
- 911 button press (GPIO IRQ)
- headphone jack insert/remove

GPIO access

The following GPIO's need to be accessed from userspace:

GTA01v4

GPS_PWRON
- allows us to power-up the GPS
MODEM_RST
- resetting the GSM Modem
MODEM_ON
- switching GSM Modem on
911_KEY
- needs to be an input device with a single key
DLGSM
- switch headphone port to GSM UART mode?
JACK_INSERT
- headphone jack insertion, reported via input device

GTA01Bv2

GSM_EN ?

Kernel

From Openmoko

Contents

General

Kernel Patchset

Kernel Configuration

Kernel building

bootable Kernel image

creating a bootable kernel image

Kernel Boot Parameters

Kernel Subsystems

Asound driver

high-level requirements

implementation

Bluetooth

Power Management

Powering up the device

Powering down the device

Asserting reset (low-active)

De-asserting reset (low-active)

Getting started

911 Button

Power Management Unit (PMU)

Power Button, Charger insertion

RTC

Watchdog

Voltage Regulators

Battery Voltage

Battery charging current

Battery temperature

Kernel TODO

Various

TS07.10 multiplex

PCF50606

backlight

vibrator

USB device driver

Sound

Power Management

GPIO access

GTA01v4

GTA01Bv2

Views

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General

Kernel Patchset

Kernel Configuration

Kernel building

bootable Kernel image

creating a bootable kernel image

Kernel Boot Parameters

Kernel Subsystems

Asound driver

high-level requirements

implementation

Bluetooth

Power Management

Powering up the device

Powering down the device

Asserting reset (low-active)

De-asserting reset (low-active)

Getting started

911 Button

Power Management Unit (PMU)

Power Button, Charger insertion

RTC

Watchdog

Voltage Regulators

Battery Voltage

Battery charging current

Battery temperature

Kernel TODO

Various

TS07.10 multiplex

PCF50606

backlight

vibrator

USB device driver

Sound

Power Management