[U-Boot] [UBOOT][PATCHv4 6/6] README: qspi usecase and testing documentation.

[Sourav Poddar <sourav.poddar@ti.com>]

On Saturday 05 October 2013 12:08 AM, Jagan Teki wrote:
> Hi Sourav,
>
> Please place these these readme files in doc/SPI/*
> All these patches tested on top of u-boot-spi.git master-probe?
Yes, this are tested on the above branch.
> On Fri, Oct 4, 2013 at 8:21 PM, Sourav Poddar<sourav.poddar@ti.com>  wrote:
>> Contains documentation and testing details for qspi flash
>> interface.
>>
>> Signed-off-by: Sourav Poddar<sourav.poddar@ti.com>
>> ---
>>   doc/README.ti_qspi_dra_test |   38 ++++++++++++++++++++++++++++++++++
>>   doc/README.ti_qspi_flash    |   47 +++++++++++++++++++++++++++++++++++++++++++
>>   2 files changed, 85 insertions(+), 0 deletions(-)
>>   create mode 100644 doc/README.ti_qspi_dra_test
>>   create mode 100644 doc/README.ti_qspi_flash
>>
>> diff --git a/doc/README.ti_qspi_dra_test b/doc/README.ti_qspi_dra_test
>> new file mode 100644
>> index 0000000..c4540ea
>> --- /dev/null
>> +++ b/doc/README.ti_qspi_dra_test
>> @@ -0,0 +1,38 @@
>> +-------------------------------------------------
>> +   Simple steps used to test the QSPI at U-Boot
>> +-------------------------------------------------
>> +
>> +For #1, build the patched U-Boot and load MLO/u-boot.img
>> +
>> +----------------------------------
>> +Boot from another medium like MMC
>> +----------------------------------
>> +
>> +DRA752 EVM # mmc dev 0
>> +DRA752 EVM # fatload mmc 0 0x82000000 MLO
>> +DRA752 EVM # fatload mmc 0 0x83000000 u-boot.img
>> +
>> +--------------------------------------------------
>> +Commands to erase/write u-boot/mlo to flash device
>> +--------------------------------------------------
>> +
>> +DRA752 EVM # sf probe 0
>> +[should detect the S25FL256S serial flash device]
>> +
>> +DRA752 EVM # sf erase 0 10000
>> +DRA752 EVM # sf erase 10000 10000
>> +DRA752 EVM # sf erase 20000 10000
>> +DRA752 EVM # sf erase 30000 10000
>> +DRA752 EVM # sf erase 40000 10000
>> +DRA752 EVM # sf erase 50000 10000
>> +DRA752 EVM # sf erase 60000 10000
>> +
>> +DRA752 EVM # sf write 82000000 0 10000
>> +DRA752 EVM # sf write 83000000 20000 70000
>> +
> These test procedure steps were done in real hw.
> Seems like written once, could be generic if you test these steps on
> real hw  and palce the same
> log here...
>
>> +For #2, set sysboot to QSPI-1 boot mode(SYSBOOT[5:0] = 100110) and power
>> +on. ROM should find the GP header at offset 0 and load/execute SPL. SPL
>> +then detects that ROM was in QSPI-1 mode (boot code 10) and attempts to
>> +find a U-Boot image header at offset 0x20000 (set in the config file)
>> +and proceeds to load that image using the U-Boot image payload offset/size
>> +from the header. It will then start U-Boot.
>> diff --git a/doc/README.ti_qspi_flash b/doc/README.ti_qspi_flash
>> new file mode 100644
>> index 0000000..1b86d01
>> --- /dev/null
>> +++ b/doc/README.ti_qspi_flash
>> @@ -0,0 +1,47 @@
>> +QSPI U-boot support
>> +------------------
>> +
>> +Host processor is connected to serial flash device via qpsi
>> +interface. QSPI is a kind of spi module that allows single,
>> +dual and quad read access to external spi devices. The module
>> +has a memory mapped interface which provide direct interface
>> +for accessing data form external spi devices.
>> +
>> +The one QSPI in the device is primarily intended for fast booting
>> +from Quad SPI flash devices.
>> +
>> +Usecase
>> +-------
>> +
>> +MLO/u-boot.img will be flashed from SD/MMC to the flash device
>> +using serial flash erase and write commands. Then, switch settings
>> +will be changed to qspi boot. Then, the ROM code will read MLO
>> +from the predefined location in the flash, where it was flashed and
>> +execute it after storing it in SDRAM. Then, the MLO will read
>> +u-boot.img from flash and execute it from SDRAM.
>> +
>> +SPI mode
>> +-------
>> +SPI mode uses mtd spi framework for transfer and reception of data.
>> +Can be used in:
>> +1. Normal mode: use single pin for transfers
>> +2. Dual Mode: use two pins for transfers.
>> +3. Quad mode: use four pin for transfer
>> +
>> +Memory mapped read mode
>> +-----------------------
>> +In this, SPI controller is configured using configuration port and then
>> +controler is switched to memory mapped port for data read.
>> +
>> +Driver
>> +------
>> +drivers/qspi/ti_qspi.c
>> +    - Newly created file which is responsible for configuring the
>> +       qspi controller and also for providing the low level api which
>> +       is responsible for transferring the datas from host controller
>> +       to flash device and vice versa.
>> +
>> +Testing
>> +-------
>> +A seperated file named README.dra_qspi_test has been created which gives all the
>> +details about the commands required to test qspi at u-boot level.
>> --
>> 1.7.1
>>
> Please use the doc/SPI/status.txt as an example format for writing new
> readme files.
>