Re: [PATCH v5 0/3] dmaengine: Initial debugfs support

From: Vinod Koul
Date: Wed Mar 11 2020 - 05:26:57 EST


On 06-03-20, 16:28, Peter Ujfalusi wrote:
> Hi,
>
> Changes sicne v4:
> - Move the dmaengine_debugfs_init() from late_initcall to be called from
> dma_bus_init to avoid races due to probe orders of drivers.
> - Separate patch to create DMA driver directories for debugfs
>
> Changes since v3:
> - Create a directory for dmaengine and name the initial file as summary
> - Function to get the debugfs root for DMA drivers if they want to place files
> - Custom dbg_summary_show implementation for k3-udma
>
> Changes since v2:
> - Use dma_chan_name() for printing the channel's name
>
> Changes since v1:
> - Use much more simplified fops for the debugfs file (via DEFINE_SHOW_ATTRIBUTE)
> - do not allow modification to dma_device_list while the debugfs file is read
> - rename the slave_name to dbg_client_name (it is only for debugging)
> - print information about dma_router if it is used by the channel
> - Formating of the output slightly changed
>
> The basic debugfs file (/sys/kernel/debug/dmaengine/summary) can be used to
> query basic information about the DMAengine usage (am654-evm):
>
> # cat /sys/kernel/debug/dmaengine/summary
> dma0 (285c0000.dma-controller): number of channels: 96
>
> dma1 (31150000.dma-controller): number of channels: 267
> dma1chan0 | 2b00000.mcasp:tx
> dma1chan1 | 2b00000.mcasp:rx
> dma1chan2 | in-use
> dma1chan3 | in-use
> dma1chan4 | in-use
> dma1chan5 | in-use
>
> Drivers can implement custom dbg_summary_show to add extended information via
> the summary file, like with the second patch for k3-udma (j721e-evm):
>
> # cat /sys/kernel/debug/dmaengine/summary
> dma0 (285c0000.dma-controller): number of channels: 24
>
> dma1 (31150000.dma-controller): number of channels: 84
> dma1chan0 | 2b00000.mcasp:tx (MEM_TO_DEV, tchan16 [0x1010 -> 0xc400], PDMA[ ACC32 BURST ], TR mode)
> dma1chan1 | 2b00000.mcasp:rx (DEV_TO_MEM, rchan16 [0x4400 -> 0x9010], PDMA[ ACC32 BURST ], TR mode)
> dma1chan2 | 2ba0000.mcasp:tx (MEM_TO_DEV, tchan17 [0x1011 -> 0xc507], PDMA[ ACC32 BURST ], TR mode)
> dma1chan3 | 2ba0000.mcasp:rx (DEV_TO_MEM, rchan17 [0x4507 -> 0x9011], PDMA[ ACC32 BURST ], TR mode)
> dma1chan4 | in-use (MEM_TO_MEM, chan0 pair [0x1000 -> 0x9000], PSI-L Native, TR mode)
> dma1chan5 | in-use (MEM_TO_MEM, chan1 pair [0x1001 -> 0x9001], PSI-L Native, TR mode)
> dma1chan6 | in-use (MEM_TO_MEM, chan4 pair [0x1004 -> 0x9004], PSI-L Native, TR mode)
> dma1chan7 | in-use (MEM_TO_MEM, chan5 pair [0x1005 -> 0x9005], PSI-L Native, TR mode)
>
> With the last patch the debugfs looks like this:
> # ls -al /sys/kernel/debug/dmaengine/
> total 0
> drwxr-xr-x 4 root root 0 Jan 1 02:00 .
> drwx------ 29 root root 0 Jan 1 02:00 ..
> drwxr-xr-x 2 root root 0 Jan 1 02:00 285c0000.dma-controller
> drwxr-xr-x 2 root root 0 Jan 1 02:00 31150000.dma-controller
> -r--r--r-- 1 root root 0 Jan 1 02:00 summary

Applied, thanks

--
~Vinod