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

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

Peter Ujfalusi (3):
dmaengine: Add basic debugfs support
dmaengine: ti: k3-udma: Implement custom dbg_summary_show for debugfs
dmaengine: Create debug directories for DMA devices

drivers/dma/dmaengine.c | 102 +++++++++++++++++++++++++++++++++++++-
drivers/dma/dmaengine.h | 16 ++++++
drivers/dma/ti/k3-udma.c | 63 +++++++++++++++++++++++
include/linux/dmaengine.h | 14 +++++-
4 files changed, 193 insertions(+), 2 deletions(-)


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