CCS/TDA2SX: How to use TDA2X to read sdcard sd-cd pin when kernel is overstart?

user6229311

Part Number: TDA2SX

Tool/software: Code Composer Studio

Hi all,

we need to detect the sdcard sd-cd pin status after kernel is started, so I found the Physical Address of the mmc1 on TRM doc. which is shown below.

but when we enter:omapconf read 0x4809C224, it runs error:

root@dra7xx-evm:~# omapconf read 0x4809C224
[ 21.049540] Unhandled fault: asynchronous external abort (0x1211) at 0x00000000
[ 21.049543] ------------[ cut here ]------------
[ 21.049563] WARNING: CPU: 0 PID: 0 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x25c/0x368()
[ 21.049569] 44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4_PER1_P3 (Read): Data Access in User mode during Functional access
[ 21.049627] Modules linked in: af_packet rpmsg_proto bc_example(O) virtio_rpmsg_bus extcon_usb_gpio pvrsrvkm(O) ahci_platform libahci_platform libahci c_can_platform c_can libata omap_aes_driver can_dev omap_sham scsi_mod rtc_omap dwc3_omap extcon omap_des omap_rng rng_core omap_remoteproc remoteproc virtio virtio_ring sch_fq_codel
[ 21.049634] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G O 4.4.84-gef1e26327a9c #6
[ 21.049637] Hardware name: Generic DRA74X (Flattened Device Tree)
[ 21.049642] Backtrace:
[ 21.049660] [<c00131c4>] (dump_backtrace) from [<c00133c0>] (show_stack+0x18/0x1c)
[ 21.049672] r7:c02de550 r6:20010193 r5:00000000 r4:c08cf690
[ 21.049683] [<c00133a8>] (show_stack) from [<c02b2108>] (dump_stack+0x8c/0xa0)
[ 21.049691] [<c02b207c>] (dump_stack) from [<c0035300>] (warn_slowpath_common+0x88/0xb8)
[ 21.049701] r7:c02de550 r6:00000093 r5:00000009 r4:c08b1d30
[ 21.049708] [<c0035278>] (warn_slowpath_common) from [<c0035368>] (warn_slowpath_fmt+0x38/0x40)
[ 21.049719] r8:00000017 r7:c07d1250 r6:00000002 r5:c07d1310 r4:c07d13b4
[ 21.049726] [<c0035334>] (warn_slowpath_fmt) from [<c02de550>] (l3_interrupt_handler+0x25c/0x368)
[ 21.049732] r3:eea04000 r2:c07d13b4
[ 21.049736] r4:80080003
[ 21.049746] [<c02de2f4>] (l3_interrupt_handler) from [<c0080be8>] (handle_irq_event_percpu+0xb4/0x160)
[ 21.049758] r10:c08fa60b r9:ee9f0300 r8:00000017 r7:00000000 r6:00000000 r5:ee9f0360
[ 21.049762] r4:eea04500
[ 21.049771] [<c0080b34>] (handle_irq_event_percpu) from [<c0080cd4>] (handle_irq_event+0x40/0x64)
[ 21.049783] r10:c08b250c r9:c063228c r8:ee808000 r7:00000000 r6:c08b7cc4 r5:ee9f0360
[ 21.049787] r4:ee9f0300
[ 21.049795] [<c0080c94>] (handle_irq_event) from [<c0084018>] (handle_fasteoi_irq+0xc0/0x194)
[ 21.049804] r7:00000000 r6:c08b7cc4 r5:ee9f0360 r4:ee9f0300
[ 21.049812] [<c0083f58>] (handle_fasteoi_irq) from [<c0080214>] (generic_handle_irq+0x2c/0x3c)
[ 21.049821] r7:00000000 r6:00000000 r5:00000017 r4:c08ac424
[ 21.049830] [<c00801e8>] (generic_handle_irq) from [<c00804ec>] (__handle_domain_irq+0x64/0xbc)
[ 21.049837] [<c0080488>] (__handle_domain_irq) from [<c000948c>] (gic_handle_irq+0x40/0x7c)
[ 21.049849] r9:c063228c r8:fa213000 r7:fa212000 r6:c08b1ef0 r5:fa21200c r4:c08b28ec
[ 21.049855] [<c000944c>] (gic_handle_irq) from [<c0013e80>] (__irq_svc+0x40/0x74)
[ 21.049858] Exception stack(0xc08b1ef0 to 0xc08b1f38)
[ 21.049863] 1ee0: 00000001 00000000 fe600000 00000000
[ 21.049868] 1f00: c08b0000 c08b24ac 00000000 00000000 c08b1f60 c063228c c08b250c c08b1f4c
[ 21.049873] 1f20: c08b1f2c c08b1f40 c0027fac c0010600 60010013 ffffffff
[ 21.049885] r9:c063228c r8:c08b1f60 r7:c08b1f24 r6:ffffffff r5:60010013 r4:c0010600
[ 21.049898] [<c00105d8>] (arch_cpu_idle) from [<c0071428>] (default_idle_call+0x28/0x34)
[ 21.049907] [<c0071400>] (default_idle_call) from [<c0071688>] (cpu_startup_entry+0x200/0x260)
[ 21.049920] [<c0071488>] (cpu_startup_entry) from [<c0629870>] (rest_init+0x90/0x94)
[ 21.049924] r7:00000000
[ 21.049934] [<c06297e0>] (rest_init) from [<c085dd88>] (start_kernel+0x400/0x40c)
[ 21.049939] r5:c08fd000 r4:c08fd040
[ 21.049946] [<c085d988>] (start_kernel) from [<80008090>] (0x80008090)
[ 21.049950] ---[ end trace 266c32fb2ebd0433 ]---
[ 21.378813] pgd = eb15b1c0
[ 21.381529] [00000000] *pgd=ad61a003, *pmd=27f848003

!!! OUPS... MEMORY ERROR @ 0x00000000 !!!
Are you sure that:
MEMORY ADDRESS IS VALID?
TARGETED MODULE IS CLOCKED?

-------------------------------------------------------------------

how could we get the status of the pin when kernel started?

over 5 years ago

0 Vishal Mahaveer over 5 years ago

TI__Mastermind 33360 points

Hi,

SD card should be actively in use for reading the registers via omapconf. Otherwise clocks are disabled by driver and you cannot read the register.

Also note that SD-CD pin is not supported by the Linux Kernel driver. We use a GPIO pin for card detect on our EVMs.

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi VIshal,

Thanks very much for you reply.

SD card should be actively in use for reading the registers via omapconf. Otherwise clocks are disabled by driver and you cannot read the register.---------So what shall we do?We need to do "omapconf read omapconf read 0x4809C224" frequently?But I do it like that, it reads errors for all the time.

Also note that SD-CD pin is not supported by the Linux Kernel driver. We use a GPIO pin for card detect on our EVMs.------------we found the SD-CD is supported by the linux kernel, when we unplug the sd-card, it's removed by linux. we just want to know the sdcard's insert or unplug status, we connect the sd-cd to the tda2x's MMC1_SDCD pin as follows, so what shall we do?

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Try doing a file transfer or some active operation on SD card and in parallel try to use omapconf to read the register.

How did you test below statement?

user6229311 said:
we found the SD-CD is supported by the linux kernel, when we unplug the sd-card, it's removed by linux.

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi VIshal,

So sorry, we set the sd-cd pin to GPIO mode, so we read the register error, now we need to read the gpio pin status to get to know the sdcard is inserted or not when the app starts, so what shall we do ?

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi Jason,

When SD card is inserted or removed, there are udev events generated to notify userspace. You can use this.
Check the link provided here for udev --> https://e2e.ti.com/support/processors/f/791/p/886453/3278431#3278431

For reading MMC register the device should be active. It doesn't matter which mode you use the pin.

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi VIshal,

We just want to use less time to read the sd-cd pin low or high status in linux userspace, so we need to install udev module?Is there any simple method to do this?Because we need to quickly read the pin status using less time, so we can't do a file transfer , that seems use more time.

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Simplest way is to read the GPIO DATA register.

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi vishal,

Could I get the GPIO DATA register address in TRM doc? not do "omapconf read 0x4809C224"?

Regards

Jason

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

We found the corresponding GPIO DATA register in TRM as follows, thanks very much!

Regards,

Jason

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi VIshal,

I've got a problem, when I read GPIO DATA register, it takes about 20 ms, so long that it makes the TDA lost packets when communicated with MCU.Why it takes more time to read the GPIO DATA register?

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi Jason,

How are you reading the register from userspace?

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

I use like this：

int testsdcdpin(void)

{

FILE * fp;

char buffer[16];

int sdcardInsert = 0;

fp=popen("omapconf read 0x4805D138","r");

fgets(buffer,sizeof(buffer),fp);

// printf("****************omapconf read 0x4805D138 result %s****************\r\n",buffer);

pclose(fp);

sdcardInsert = (buffer[1] - '0') >> 3;

return sdcardInsert;

}

then it takes 20ms.

Regards

Vishal

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi,

This is not a good method to use omapconf in the application. ompaconf is a debug tool.

Another approach could be to mmap the register memory in your application and read the value. But, note that mmap is good for test purposes, mmap relies on /dev/mem interface and not sure if this will be kept in production kernels.

Could you instead check if /proc/interrupts entry works for you? check the one for "mmc cd" and check when the count increases.

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

I can see the interrupts for mmc0(sd card) as shown below, but we need to get the sd card insert status, could the interrupt indicate the insertion status?By the way, how to use the mmap in the application?

Regards,

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi,

I was talking about the one for GPIO used for card detect.
Look at the entry that says "4805d000.gpio 27", every time card is inserted or removed, the count should increase.

Regards,
Vishal

0 Vishal Mahaveer over 5 years ago in reply to Vishal Mahaveer

TI__Mastermind 33360 points

You can see a mmap example in below link
https://git.ti.com/cgit/glsdk/example-applications/tree/cpuload-plugins/read32k.c

0 Vishal Mahaveer over 5 years ago in reply to Vishal Mahaveer

TI__Mastermind 33360 points

Hi,

You have started a new thread, can we close this one?
https://e2e.ti.com/support/processors/f/791/t/899942

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

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CCS/TDA2SX: How to use TDA2X to read sdcard sd-cd pin when kernel is overstart?