Function spl_mmc_load_image() not returns when i2c_read() API is used in it in am335x.

nilesh kadivar

Hi,

I have EEPROM over i2c on address 0x50 in am335x. After MLO is loaded it tries to call function board_init_r of file spl.c. From this function it calls spl_mmc_load_image() of file spl_mmc.c.

Now when i puts below code in fuction spl_mmc_load_image() of file spl_mmc.c to read eeprom value then it reads correct value and comes at the end of the function.But it not returns back in function board_init_r() of spl.c file from where this function is called. So my execution is hanged at this point. If i comment out below code then everything works fine. Also putting this code in spl.c instead of spl_mmc.c in function board_init_r() before calling spl_mmc_load_image() also works fine with correct value without hanging.

uchar read_val;

printf("reading value :");

i2c_read(0x50, 0x1, 1, &read_val, 0);
printf("%d\n", read_val);

So, the problem is that i2c reading works fine but defining it in spl_mmc_load_image() not returns control to function from where it is called. Also i verified that print at last line of spl_mmc_load_image() comes.

Please provide me a solution.

Thanks in advance.

Regards,

Nilesh

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

Which U-boot version are you using (from which SDK)?

0 nilesh kadivar over 8 years ago in reply to Biser Gatchev-XID

Intellectual 940 points

Hi
U-Boot version is u-boot-2014.07-g7e537bf and sdk is ti-processor-sdk-linux-am335x-evm-01.00.00.00-Linux-x86-Install.bin
Thanks,
Nilesh

0 Biser Gatchev-XID over 8 years ago in reply to nilesh kadivar

TI__Guru**** 393215 points

Thanks. I will forward this to the software team.

0 nilesh kadivar over 8 years ago in reply to Biser Gatchev-XID

Intellectual 940 points

Hi Biser,

Any update on this? Also i am facing issue that when in common/main.c i used i2c_read(0x50, 0x1, 1, &read_val, 0); it not comes out of this api and execution stops at this point.

Can you please help on this?

Thanks in advance.

Regards,

Nilesh

0 Biser Gatchev-XID over 8 years ago in reply to nilesh kadivar

TI__Guru**** 393215 points

Feedback will be posted directly here when available.

0 Biser Gatchev-XID over 8 years ago in reply to nilesh kadivar

TI__Guru**** 393215 points

How is your I2C pinmux configured? Have you seen the note under Table 21-5 in the AM335X TRM Rev. M:

"I2C_SCL output signal is also used as a retiming input. The associated CONF_<module>_<pin>_RXACTIVE bit for the output clock must be set to 1 to enable the clock input back to the module."

0 Yordan Kovachev over 8 years ago

TI__Guru**** 161600 points

Hi,

In addition to comments done by Biser.

You're using i2c_read() API the wrong way. Have a look at its implementation in drivers/i2c/i2c_core.c:
int i2c_read(uint8_t chip, unsigned int addr, int alen,
uint8_t *buffer, int len)
{
return I2C_ADAP->read(I2C_ADAP, chip, addr, alen, buffer, len);
}

I tested this on my beaglebone black. I added the following code in spl_mmc.c:
#endif
hang();
}
/*my stuff for test*/
++ #define DEBUG
++ debug("#########reading EEPROM value#########\n");
++ i2c_read(0x0, CONFIG_SYS_I2C_EEPROM_ADDR, 0x1, &read_val, 0);
++ printf("#########value at eeprom is: %d#########\n", read_val);
++ #undef DEBUG
boot_mode = spl_boot_mode();
switch (boot_mode) {
case MMCSD_MODE_RAW:

As a result my MLO prints a value read from i2c0 at address 0x50 (EEPROM):
#########value at eeprom is: 64#########

Best Regards,
Yordan

0 nilesh kadivar over 8 years ago in reply to Yordan Kovachev

Intellectual 940 points

Hi Yordan,

Thanks for your reply.

I did same thing as you. below is my output. Last line "value at eeprom is: 64" is same as you received but it's not true EEPROM value. Also in log we can see that it shows i2c_read error.

#########reading EEPROM value#########
i2c_read: error waiting for addr ACK (status=0x116)
#########value at eeprom is: 64#########

Please help on this to solve this error.

Thanks,
Nilesh

0 nilesh kadivar over 8 years ago in reply to nilesh kadivar

Intellectual 940 points

Hi Yordan,

Is this same behaviour at your side?

Regards,

Nilesh

0 nilesh kadivar over 8 years ago in reply to nilesh kadivar

Intellectual 940 points

Hi Yordan

It works for me by using it as below.

#define DEBUG
debug("#########reading EEPROM value#########\n");
i2c_read(CONFIG_SYS_I2C_EEPROM_ADDR, 0x0, 0x1, &read_val, 1);
printf("#########value at eeprom is: %d#########\n", read_val);
#undef DEBUG

Thanks,

Nilesh

Processors

Processors forum

Function spl_mmc_load_image() not returns when i2c_read() API is used in it in am335x.