CCS/TDA2SX: Could handle SD card insertion and removal events as polling instead of interrupt processing

user6229311

Part Number: TDA2SX

Tool/software: Code Composer Studio

Hi all,

We use tda2xx to communicate with MCU, the MCU send the packets to the tda2xx with 2ms period, and then wait 10ms for tda2xx reback the packets. When we remove the sd card from tda2xx board, the tda2xx generates an interrupt to handle related events(shown as below printfs), then it can't reback the packets from MCU within 10ms, it's so terrible for we need to reback the packets to MCU in time.

What shall we do with the sd card removal events?Shall we do it with polling mode?

remove printfs:

root@dra7xx-evm:~# [ 38.232174] mmc0: card 59b4 removed

Broadcast message from systemd-journald@dra7xx-evm (Fri 2020-04-24 09:14:08 UTC):

systemd[1]: Caught <ABRT>, dumped core as pid 25961.

Broadcast message from systemd-journald@dra7xx-evm (Fri 2020-04-24 09:14:08 UTC):

systemd[1]: Freezing execution.

systemd-journald[127]: Failed to send WATCHDOG=1 notification message: Connection refused

systemd-journald[127]: Failed to send WATCHDOG=1 notification message: Connection refused………………(repeat this printf, and the tda2xx can't reback the packets to MCU with 10ms)

insertion printfs:

root@dra7xx-evm:~# [ 62.743626] mmc0: host does not support reading read-only switch, assuming write-enable
[ 62.754761] mmc0: new ultra high speed SDR104 SDXC card at address 59b4
[ 62.773987] mmcblk0: mmc0:59b4 SDU1 58.9 GiB
[ 62.783167] mmcblk0: p1 p2
[ 63.062903] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
[ 63.076297] EXT4-fs (mmcblk0p2): recovery complete
[ 63.081253] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)

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

By the way, our rootfs is set to read-only filesystem

Regards

Jason

over 5 years ago

0 Vishal Mahaveer over 5 years ago

TI__Mastermind 33360 points

Hi Jason,

Could you provide more details on how the communication happens between MCU and TDA2X?
Is the observation seen on only during card removal? or both during insertion and removal?

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

Both during insertion and removal. It's the real-time sockets communication between TDA and MCU.

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi Jason,

Is the socket communication on TDA handled by some Linux driver?

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

We use no Linux drivers.TDA is server and MCU is client,

use socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP) to creat socket

use recvfrom to receive sockets from MCU

then use sendto to reback to MCU

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Ok, can you try increasing priority of your server process?

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

I've increased the socket server process to the highest priority, but it cannot be higher than the interrupt priority（i.e., suddenly pull out the SD card), so I would like to set SD card insertion or removal events to polling mode.But what shall I do?

Regards

Jason

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

I try to define the sd-cd pin as poll mode, and I found in the dts files:

dra7-evm.dts file:

dra7.dtsi file:

the sd-cd pin is &gpio6-27,how could I set the pin in poll mode, not the interrupt mode?

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi Jason,

Card detect GPIO is handled by core MMC driver of Linux Kernel.

Regards,
Vishal

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

TI__Mastermind 33360 points

Hi Jason,

Could you try the below and check the behavior?

- Delete 'cd-gpios' property for mmc1 node.
- Add 'broken-cd' property instead.

First check if mmc1 is still functional and then do your tests.
This combination is not testes on our SDK, but according to the comment in MMC driver of kernel, 'broken-cd' property leads to polling mode for card detect.

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

I tried it, but it still causes communication delay because the handling of SD card insertion and removal events is blocked.I wonder if it can be changed to non-blocking to handle SD card insertion and removal events?

Regards

Jason

0 Vishal Mahaveer over 5 years ago in reply to user6229311

TI__Mastermind 33360 points

Hi Jason,

Those settings are for switching card detect to polling mode.

Is SD card insertion/removal the only event that interferes with the MCU communication?

Regards,
Vishal

0 user6229311 over 5 years ago in reply to Vishal Mahaveer

Expert 1805 points

Hi Vishal,

This is currently the case, other hardware interfaces are fixed, such as camera input interface, video output interface, and network interface, and the SD card may be hot swapped by the user at any time, because it is used to store the driving recorder data.At present, we temporarily accept the delay of 40ms due to the hot swap of the SD card. Event, if there is a better solution in the future, please let me know, thanks a lot.

Regards

Jason

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CCS/TDA2SX: Could handle SD card insertion and removal events as polling instead of interrupt processing