Hi again,
On Friday 20 August 2010 03:35:57 pm Stefano Babic wrote:
Just figured out one big mistake. I was debugging spi_flash.c, and had CONFIG_ENV_IS_IN_SPI_FLASH set. That means, first SPI access is done before malloc is available, and guess what? spi_setup_slave() uses malloc ;-)
I have CONFIG_ENV_IS_IN_SPI_FLASH set, too. I try to figure out how the functions are called, but I do not get the same issue. I set with the debugger two breakpoints, one in mem_malloc_init and the second one in spi_setup_slave. I see that mem_alloc_init is hit first, and when spi_setup_slave is called, malloc is available. I get a valid pointer for the private structure. It seems there something in our config files that makes the things different. I do not yet know why.
Are you sure? In arch/arm/lib/board.c function start_armboot(), init_sequence is processed first, which contains env_init() before dram_init() and just after completing init_sequence, mem_malloc_init() is called. How can you have working malloc then?
The C++ comments show original code, the line below is new.
Understood, if malloc is not called, we have to use static or (better) try to call mem_malloc_init() first
I don't know if that is possible. I know that physically RAM is initialized before u-boot even starts (it runs from RAM), but logically, dram_init() is called _after_ env_init(), so I'm not sure if you are supposed to call mem_malloc_init() in env_init()...
I see a one byte access followed by a 5 byte access,
That is correct, you see the code in spi_flash.c. First the ID command is sent (0x97), without reading nothing (that is, din is NULL). Then the answer is read (dout is NULL), and the id buffer is 5 bytes long.
I am slowly progressing... now the transfer succeeds, but I only read FF ;-)
[...]
I am trying another approach. As the MX51 has 32 bytes FIFO, it makes sense to use it and not send a single word, if we can. This must not change the behavior for the MX31, because this processor has no FIFO and a single word can be sent. So I replaced completely spi_xfer, and the logic you put in spi_xfer I have (more or less, I have not checked in details) moved inside the spi_xcgh:single, that now has the meaning for me as single transation: up to 1 word for i.MX31, up to 32 words (128 bytes) for i.MX51.
Take into account that loading the kernel using a single word takes a lot of time..
A good point. I was following the premise that u-boot drivers should be simple, but a little bit of speed for booting is surely not a bad idea ;-)
However, I am currently working on several issues for MX51. It should be nice to know which are your plans to save both some time ;-)
Well, I am in a bit of a hurry, and essentially what I need is to be able to access SPI-nor flash (spansion type) for environment and booting linux. MMC/SD access would be nice, but is not yet necessary.
Ok, quite the same. I have a ST flash, but we get the same problems, I see.
I am just now picking up where I left last week, so give me a few hours and I should have something working, I guess.
I know. I thought to do it in two steps: Fix mxc_spi.c with a workaround for the pmic driver (which amounts to '#define spi_xfer spi_xfer_fsl' at the beginning of this driver basically) and fix the pmic driver later, since it is probably not trivial, and needs to be done carefully (you know, one can smoke a board by mistake :-)
I know, this makes funny setting voltages via software....
I always say: "Electronics work on smoke. If the smoke escapes, it stops working" :-)
Best regards,