Request for LS1012A EDMA module program memory copy example.

[Gyosun]

Hello, NXP,

I want to use edma on the LS1012A board. I am using the LSDK1812 SDK, and I would appreciate it if you could share a memory copy example using a kernel module program. An example that can be applied to an application would also be helpful.

I am requesting this urgently, so I would appreciate your prompt response.

Thank you.

Gyosun,

[yipingwang]

For eDMA driver, please refer to drivers/dma/fsl-edma.c.

Use the slave device which deploys the eDMA functionality to verify the eDMA driver, below is a verification with the I2C
salve.
root@ls1021aqds:~# i2cdetect 0
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-0.
I will probe address range 0x03-0x77.
Continue? [Y/n]
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- 69 -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
root@ls1021aqds:~# i2cdump 0 0x69 i
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 05 07 ff ff 5d 55 10 55 11 05 1e 00 e8 03 b5 ff ??..]U?U???.???.
10: ff e8 03 95 00 00 00 00 aa fe 9a 00 00 00 00 78 .???....???....x
20: 05 12 04 ff 00 7f 40 14 1d 60 3c 83 05 00 40 00 ???..?@??`<??.@.
30: fe 80 c6 29 00 00 00 7a 00 ff ff ff ff ff ff ff ???)...z........
40: 05 07 ff ff 5d 55 10 55 11 05 1e 00 e8 03 b5 ff ??..]U?U???.???.
50: ff e8 03 95 00 00 00 00 aa fe 9a 00 00 00 00 78 .???....???....x
60: 05 12 04 ff 00 7f 40 14 1d 60 3c 83 05 00 40 00 ???..?@??`<??.@.
70: fe 80 c6 29 00 00 00 7a 00 ff ff ff ff ff ff ff ???)...z........
80: 07 ff ff 5d 55 10 55 11 05 1e 00 e8 03 b5 ff ff ?..]U?U???.???..
90: e8 03 95 00 00 00 00 aa fe 9a 00 00 00 00 78 00 ???....???....x.
a0: 12 04 ff 00 7f 40 14 1d 60 3c 83 05 00 40 00 fe ??..?@??`<??.@.?
b0: 80 c6 29 00 00 00 7a 00 ff ff ff ff ff ff ff ff ??)...z.........
c0: 07 ff ff 5d 55 10 55 11 05 1e 00 e8 03 b5 ff ff ?..]U?U???.???..
d0: e8 03 95 00 00 00 00 aa fe 9a 00 00 00 00 78 00 ???....???....x.
e0: 12 04 ff 00 7f 40 14 1d 60 3c 83 05 00 40 00 fe ??..?@??`<??.@.?
f0: 80 c6 29 00 00 00 7a 00 ff ff ff ff ff ff ff ff ??)...z.........
root@ls1021aqds:~# cat /proc/interrupts
CPU0 CPU1
29: 0 0 GIC 29 arch_timer
30: 5563 5567 GIC 30 arch_timer
112: 260 0 GIC 112 fsl-lpuart
120: 32 0 GIC 120 2180000.i2c

121: 0 0 GIC 121 2190000.i2c
167: 8 0 GIC 167 eDMA
IPI0: 0 1 CPU wakeup interrupts
IPI1: 0 0 Timer broadcast interrupts
IPI2: 1388 1653 Rescheduling interrupts
IPI3: 0 0 Function call interrupts
IPI4: 2 4 Single function call interrupts
IPI5: 0 0 CPU stop interrupts
Err: 0
root@ls1021aqds:~#

[Gyosun]

Hi yipingwang,

Thank you for your response.
I apologize for the delay in getting back to you.
I'm looking for a memory-to-memory example using fsl-edma.c.
If you happen to have one, could you please share it with me?

Thanks,
Gyosun.

[Gyosun]

Additionally, we tested:

Looking at the fsl-edma.c code of the LSDK1812 I am using,

It seems to support device_prep_slave_sg and device_prep_dma_cyclic.

dma_cap_set(DMA_PRIVATE, fsl_edma->dma_dev.cap_mask);
dma_cap_set(DMA_SLAVE, fsl_edma->dma_dev.cap_mask);
dma_cap_set(DMA_CYCLIC, fsl_edma->dma_dev.cap_mask);

fsl_edma->dma_dev.device_prep_slave_sg = fsl_edma_prep_slave_sg;
fsl_edma->dma_dev.device_prep_dma_cyclic = fsl_edma_prep_dma_cyclic;
fsl_edma->dma_dev.device_config = fsl_edma_slave_config;

So, I have written as follows.

dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE,mask);  
dma_chan = dma_request_channel(mask,0,NULL);
if(dma_chan == 0) printk("failed to request DMA channel\n");
else printk("passed to request DMA channel %d\n", dma_chan->chan_id);

I have been assigned an ID without any issues.

static ssize_t dma_memcpy_sg(uint64_t paddr_dst, uint64_t paddr_src, size_t count)
{
struct dma_async_tx_descriptor *tx_desc = NULL;
    struct dma_device *dma_dev = dma_chan->device;
    dma_cookie_t cookie;
    int ret, src_cnt = 1;
enum dma_transfer_direction dir = DMA_DEV_TO_MEM;
struct scatterlist sg;
struct dma_slave_config dma_config;

    /* Configure the slave DMA */
    memset(&dma_config, 0, sizeof(dma_config));
    dma_config.direction = DMA_DEV_TO_MEM;
    dma_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
    dma_config.src_addr = dma_buf_handle_tx;
    dma_config.src_maxburst = 1;
    //ret = dmaengine_slave_config(dma_chan, &dma_config);
    ret = dma_dev->device_config(dma_chan, &dma_config);
    if (ret) {
        pr_err("Failed to configure DMA slave\n");
    }

sg_init_table(&sg, src_cnt);
sg_dma_address(&sg) = (uint64_t)paddr_dst;
sg_dma_len(&sg) = count;

    //tx_desc = dmaengine_prep_slave_sg(dma_chan,
    tx_desc = dma_dev->device_prep_slave_sg(dma_chan,
                     &sg,
                     src_cnt,
                     dir,
                     DMA_PREP_INTERRUPT | DMA_CTRL_ACK, NULL);
    if (!tx_desc) {
        pr_err("[%d]Failed to prepare DMA memcpy\n", __LINE__);
        return -1;
    }

    tx_desc->callback = complete_rx_dma;
    //cookie = dmaengine_submit(tx_desc);
    cookie = tx_desc->tx_submit(tx_desc);
    if (dma_submit_error(cookie)) {
        pr_err("[%d]Failed to do DMA tx_submit\n",__LINE__);
        return -1;
    }
    
    dma_async_issue_pending(dma_chan);
}
When I execute the dma_memcpy_sg function, there are no pr_err messages, and there is no increase in the edma interrupt in /proc/interrupt. I'm not able to perform the copy, so I would appreciate some advice on what could be the problem.

Thanks,
Gyosun.

[yipingwang]

Please refer to the following update from the AE team.

Did customer try to transfer with single descriptor?

I saw customer use DMA_DEV_TO_MEM for tx, what's the direction of the transfer? Is it from device to memory?

We haven't example for scattergather transfer on hand, customer can refer to drivers/i2c/busses/i2c-imx.c for single transfer.

[Gyosun]

Hi yipingwang,

Thank you for your response.

I am currently experimenting with memory-to-memory transfers, but ultimately, I am aiming for memory-to-PCIe transfers.

Since I need to allocate the BAR (Base Address Register) and transfer data from memory to PCIe, I wanted to explore memory-to-memory transfers first.

If you have any relevant examples to share, please let me know.

Thanks,

Gyosun.

[yipingwang]

Please refer to the following update from the AE team.

I suggest customer to try single transfer first, then we can see if their DMA can work normally. And customer should use DMA_MEM_TO_MEM for copying between memory.

[Gyosun]

Hi yipingwang,

Is the approach you suggested applicable in the LSDK18.12 LS1012A environment?

If so, could you please provide the location of the relevant Linux source code for DMA_MEM_TO_MEM? 

Thanks,

Gyosun.

[yipingwang]

Here is the definition of DMA direction, in include/linux/dmaengine.h
/**
* enum dma_transfer_direction - dma transfer mode and direction indicator
* @dma_MEM_TO_MEM: Async/Memcpy mode
* @dma_MEM_TO_DEV: Slave mode & From Memory to Device
* @dma_DEV_TO_MEM: Slave mode & From Device to Memory
* @dma_DEV_TO_DEV: Slave mode & From Device to Device
*/
enum dma_transfer_direction {
DMA_MEM_TO_MEM,
DMA_MEM_TO_DEV,
DMA_DEV_TO_MEM,
DMA_DEV_TO_DEV,
DMA_TRANS_NONE,
};

We haven't example code on hand. There is the usage of it can be searched in kernel code. Of can customer share their test file then we can try locally?

[Gyosun]

Hi yipingwang,

I have attached the test example that I have tested.

ex_edma_drv_test.tar 

I have compiled it with LSDK18.12.
After the compilation, when the dev_pci_xdma_ls1012a.ko file is generated,
it should be copied to the board.
By performing the following three steps, the test results will be displayed easily.

insmod dev_pci_xdma_ls1012a.ko
echo 0 > /sys/kernel/kobject_example/test_mode
echo 1 > /sys/kernel/kobject_example/test_mode

Please analyze the reasons why it is not functioning when executed on the actual board.

Thanks,

Gyosun.

[yipingwang · Accepted solution]

There is one patch realizing edma memcopy, you can apply it or use latest kernel which kernel version> 6.1.1.
Also there is some tiny errors in main.c file, we had modified it.
Attach the log for your reference.

[Gyosun]

Hi yipingwang,

Oh my god!!

This aligns with what we desired.
I have confirmed that it works well with the LSDK 18.12 patch.
It would be great if the new LSDK version also includes DMA_MEMCPY and DMA_SG.

Thank you so much.

Gyosun.