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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright © 2011 by Amaury Pouly
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
/* IMPORTANT NOTE This file is used by both Rockbox (firmware and bootloader)
* and the dualboot stub. The stub #include this file directly, so make sure
* this file is independent and does not requires anything from the firmware */
#include "dualboot-imx233.h"
#ifdef HAVE_DUALBOOT_STUB
/** Persistent registers usage by the OF based on the Firmware SDK
* and support for firmware upgrades in Rockbox
* (this includes the Fuze+, ZEN X-Fi3, NWZ-E360/E370/E380)
*
* The following are used:
* - PERSISTENT0: mostly standard stuff described in the datasheet
* - PERSISTENT1: mostly proprietary stuff + some bits described in the datasheet
* - PERSISTENT2: used to keep track of time (see below)
* - PERSISTENT3: proprietary stuff
* - PERSISTENT4: unused
* - PERSISTENT5: used by Rockbox to tell the dualboot stub what to do
*
* In particular, the following bits are involved in the firmware upgrade process
* and thus worth mentioning (Px means PERSISTENTx). Some of this information
* might not be entirely accurate:
* - P1[18]: when 0, indicates to the freescale boot stub to start the updater
* rather than the main firmware (play) or the usb firmware (host)
* - P1[22]: when 0, indicates that the OF database/store should be rebuilt
* - P3[10]: when 0, indicates that the firmware has been upgraded
* - P3[11]: when 1, indicates to the freescale boot stub to boot without
* requiring the user to hold the power button for a small delay
* - P3[12]: when 1, indicates that the internal drive or micro-sd card was
* modified in USB mode
* - P3[16]: when 1, indicates that a firmware upgrade was attempted but aborted
* due to a too low battery
*
* To understand how all this works out together, recall that the boot sequence
* usually looks as follows (fslx = freescale boot stub stage x, in section 0
* of the firmware; rb = rockbox dualboot stub), where arrows indicate boot flow
* (since every stage can choose to continue in the same section or jump to another):
*
* +---> host (usb)
* |
* fsl0 -> fsl1 -> fsl2 -> rb -> fsl3 -> fsl4 (updater)
* | |
* | +---> play (firmware)
* |
* +-----------> rock (bootloader) (-> loads rockbox)
*
* Note that the exact number of fsl stages is device-dependent, there 5 on the
* fuze+, 3 on the NWZs for example.
*
* The fsl3 decides which stage to boot based on the following logic (order is
* important):
* - if P1[18] is 0, it goes to fsl4, to perform a firmware upgrade
* - if usb is plugged, it goes to host, the OF USB mode
* - if P1[22] is 1, it requires the user to hold the power button for small
* delay and aborts boot if this is not the case
* - it goes to play, the OF normal firmware
*
* The fsl4 (updater) performs the following action:
* - it clears P1[18] so that next boot will be a normal boot (ie NOT updater)
* - if firmware.sb does not exist or is invalid, it reboots
* - if the battery is too low for an upgrade, it sets P3[16]
* otherwise, it performs a firmware upgrade and clear P1[22]
* - it shutdowns
*
* The play (firmware) performs the following actions:
* - if P1[22] is 0 or P3[12] is 1, it rebuilds the store (the 'loading' screen)
* and set P1[22] to 1 and P3[12] to 0
* - if P3[16] is 1, it displays a 'battery was too low to upgrade' message
* and clears P3[16]
* - if P3[10] is 0, it displays a 'firmware was successfully upgraded' message
* and sets P3[10] to 1
* - it performs its usual (crappy) functions
*
* The host (USB) performs the following actions:
* - it clears P1[18] so that the next boot will run the updater
* - it sets P3[11] to 1 so that the device will reboot without user intervention
* at the end
* - if the host modifies the internal drive or micro-SD card, it sets P3[12]
* to 1 and clears P1[22]
* - after USB is unplugged, it reboots
*
* Thus a typical firmware upgrade sequence will look like this:
* - initially, the main firmware is running and flags are in the following state:
* P1[18] = 1 (normal boot)
* P1[22] = 1 (store is clean)
* P3[10] = 1 (firmware has not been upgraded)
* P3[11] = 0 (user needs to hold power button to boot)
* P3[12] = 0 (drive is clean)
* - the user plugs the USB cable, play reboots, fsl3 boots to host because
* P1[18] = 1, the users put firmware.sb on the drive, thus modifying its
* content and then unplugs the drive; the device reboots with the following
* flags:
* P1[18] = 0 (updater boot)
* P1[22] = 0 (store is dirty)
* P3[10] = 1 (firmware has not been upgraded)
* P3[11] = 1 (user does not needs to hold power button to boot)
* P3[12] = 1 (drive is dirty)
* - fsl3 boots to the updater because P1[18] = 0, the updater sees firmware.sb
* and performs a firmware upgrade; the device then shutdowns with the following
* flags:
* P1[18] = 1 (normal boot)
* P1[22] = 0 (store is dirty)
* P3[10] = 0 (firmware has been upgraded)
* P3[11] = 1 (user does not needs to hold power button to boot)
* P3[12] = 1 (drive is dirty)
* - the user presses the power button, fsl3 boots to play (firmware) because
* P1[18] = 1, it rebuilds the store because P1[22] is clear, it then display
* a message to the user saying that the firmware has been upgraded because
* P3[10] is 0, and it resets the flags to same state as initially
*
* Note that the OF is lazy: it reboots to updater after USB mode in all cases
* (even if firmware.sb was not present). In this case, the updater simply clears
* the update flags and reboot immediately, thus it looks like a normal boot.
*
*
* To support firmware upgrades in Rockbox, we need to two things:
* - a way to tell rb (rockbox dual stub) to continue to fsl3 instead of booting
* rock (our bootloader)
* - a way to setup the persistent bits so that fsl3 will boot to fsl4 (updater)
* instead of booting host (usb) or play (firmware)
*
* The approach taken is to use PERSISTENT5 to tell the dualboot stub what we want
* to do. Since previous dualboot stubs did not support this, and that other actions
* may be added in the future, the registers stores both the capabilities of the
* dualboot stub (so that Rockbox can read them) and the actions that the dualboot
* stub must perform (so that Rockbox can write them). The register is encoded
* so that older/random values will be detected as garbage by newer Rockbox and
* dualboot stub, and that a value of 0 for a field always behaves as when it did
* not exist. More precisely, the bottom 16-bit must be 'RB' and
* the top 16-bit store the actual data. The following fields are currently defined:
* - CAP_BOOT(1 bit): supports booting to OF and UPDATER using the BOOT field
* - BOOT(2 bits): sets boot mode
*
* At the moment, BOOT supports three values:
* - IMX233_BOOT_NORMAL: the dualboot will do a normal boot (booting to Rockbox
* unless the user presses the magic button that boots to the OF)
* - IMX233_BOOT_OF: the dualboot stub will continue booting with fsl3 instead
* of Rockbox, but it will not touch any of OF persistent bits (this is useful
* to simply reboot to the OF for example)
* - IMX233_BOOT_UPDATER: the dualboot will setup OF persistents bits and
* continue so that fsl3 enters fsl4 (updater)
* In this scheme, Rockbox does not have to care about how exactly those actions
* are achieved, only the dualboot stub has to deal with the persistent bits.
* When the dualboot stubs see either OF or UPDATER, it clears BOOT back
* to NORMAL before continuing, so as to avoid any boot loop.
*
*/
#include "regs/rtc.h"
/* the persistent register we use */
#define REG_DUALBOOT HW_RTC_PERSISTENT5
/* the bottom 16-bit are a magic value to indicate that the content is valid */
#define MAGIC_MASK 0xffff
#define MAGIC_VALUE ('R' | 'B' << 8)
/* CAP_BOOT: 1-bit (16) */
#define CAP_BOOT_POS 16
#define CAP_BOOT_MASK (1 << 16)
/* BOOT field: 2-bits (18-17) */
#define BOOT_POS 17
#define BOOT_MASK (3 << 17)
unsigned imx233_dualboot_get_field(enum imx233_dualboot_field_t field)
{
unsigned val = HW_RTC_PERSISTENT5;
/* if signature doesn't match, assume everything is 0 */
if((val & MAGIC_MASK) != MAGIC_VALUE)
return 0;
#define match(field) \
case DUALBOOT_##field: return ((val & field##_MASK) >> field##_POS);
switch(field)
{
match(CAP_BOOT)
match(BOOT)
default: return 0; /* unknown */
}
#undef match
}
void imx233_dualboot_set_field(enum imx233_dualboot_field_t field, unsigned fval)
{
unsigned val = HW_RTC_PERSISTENT5;
/* if signature doesn't match, create an empty register */
if((val & MAGIC_MASK) != MAGIC_VALUE)
val = MAGIC_VALUE; /* all field are 0 */
#define match(field) \
case DUALBOOT_##field: \
val &= ~field##_MASK; \
val |= (fval << field##_POS) & field##_MASK; \
break;
switch(field)
{
match(CAP_BOOT)
match(BOOT)
default: break;
}
HW_RTC_PERSISTENT5 = val;
#undef match
}
#endif /* HAVE_DUALBOOT_STUB */
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