From e937cc1dd7966df33a478943817302502a164e25 Mon Sep 17 00:00:00 2001 From: Peter Ujfalusi Date: Fri, 6 Mar 2020 16:28:37 +0200 Subject: dmaengine: Add basic debugfs support Via the /sys/kernel/debug/dmaengine/summary users can get information about the DMA devices and the used channels. Example output on am654-evm with audio using two channels and after running dmatest on 4 channels: 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 For slave channels we can show the device and the channel name a given channel is requested. For non slave devices the only information we know is that the channel is in use. DMA drivers can implement the optional dbg_summary_show callback to provide controller specific information instead of the generic one. It is easy to extend the generic dmaengine_summary_show() to print additional information about the used channels. I have taken the idea from gpiolib and clk subsystems. Signed-off-by: Peter Ujfalusi Link: https://lore.kernel.org/r/20200306142839.17910-2-peter.ujfalusi@ti.com Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index d3672f065a64..72920b5cf2d7 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -300,6 +300,8 @@ struct dma_router { * @chan_id: channel ID for sysfs * @dev: class device for sysfs * @name: backlink name for sysfs + * @dbg_client_name: slave name for debugfs in format: + * dev_name(requester's dev):channel name, for example: "2b00000.mcasp:tx" * @device_node: used to add this to the device chan list * @local: per-cpu pointer to a struct dma_chan_percpu * @client_count: how many clients are using this channel @@ -318,6 +320,9 @@ struct dma_chan { int chan_id; struct dma_chan_dev *dev; const char *name; +#ifdef CONFIG_DEBUG_FS + char *dbg_client_name; +#endif struct list_head device_node; struct dma_chan_percpu __percpu *local; @@ -806,7 +811,9 @@ struct dma_filter { * called and there are no further references to this structure. This * must be implemented to free resources however many existing drivers * do not and are therefore not safe to unbind while in use. - * + * @dbg_summary_show: optional routine to show contents in debugfs; default code + * will be used when this is omitted, but custom code can show extra, + * controller specific information. */ struct dma_device { struct kref ref; @@ -892,6 +899,10 @@ struct dma_device { struct dma_tx_state *txstate); void (*device_issue_pending)(struct dma_chan *chan); void (*device_release)(struct dma_device *dev); + /* debugfs support */ +#ifdef CONFIG_DEBUG_FS + void (*dbg_summary_show)(struct seq_file *s, struct dma_device *dev); +#endif }; static inline int dmaengine_slave_config(struct dma_chan *chan, -- cgit v1.2.3-59-g8ed1b