Messages in this thread | | | Subject | Re: [PATCH] dmaengine: pl330: introduce debugfs interface | From | Katsuhiro Suzuki <> | Date | Sun, 17 Mar 2019 18:58:54 +0900 |
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Hello Vinod,
Thank you for your comment. I fix it all and re-post v2 patch.
On 2019/03/16 2:00, Vinod Koul wrote: > On 15-03-19, 03:49, Katsuhiro Suzuki wrote: >> This patch adds debugfs interface to show the relationship between >> DMA threads (hardware resource for transferring data) and DMA >> channel ID of DMA slave. >> >> Typically, PL330 has many slaves than number of DMA threads. >> So sometimes PL330 cannot allocate DMA threads for all slaves even >> if an user specify DMA channel ID in devicetree. This interface will > > a user :) > >> be useful for checking that DMA threads are allocated or not. >> >> Below is an output sample: >> >> $ sudo cat /sys/kernel/debug/ff1f0000.dmac >> PL330 physical channels: >> THREAD: CHANNEL: >> -------- ----- >> 0 8 >> 1 9 >> 2 11 >> 3 12 >> 4 14 >> 5 15 >> 6 10 >> 7 -- >> >> Signed-off-by: Katsuhiro Suzuki <katsuhiro@katsuster.net> >> --- >> drivers/dma/pl330.c | 51 +++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 51 insertions(+) >> >> diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c >> index eec79fdf27a5..aab71863757c 100644 >> --- a/drivers/dma/pl330.c >> +++ b/drivers/dma/pl330.c >> @@ -11,6 +11,7 @@ >> * (at your option) any later version. >> */ >> >> +#include <linux/debugfs.h> >> #include <linux/kernel.h> >> #include <linux/io.h> >> #include <linux/init.h> >> @@ -2896,6 +2897,55 @@ static irqreturn_t pl330_irq_handler(int irq, void *data) >> BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | \ >> BIT(DMA_SLAVE_BUSWIDTH_8_BYTES) >> >> +#ifdef CONFIG_DEBUG_FS >> +static int pl330_debugfs_show(struct seq_file *s, void *data) >> +{ >> + struct pl330_dmac *pl330 = s->private; >> + int chans, pchs, ch, pr, found; >> + >> + chans = pl330->pcfg.num_chan; >> + pchs = pl330->num_peripherals; >> + >> + seq_puts(s, "PL330 physical channels:\n"); >> + seq_puts(s, "THREAD:\t\tCHANNEL:\n"); >> + seq_puts(s, "--------\t-----\n"); >> + for (ch = 0; ch < chans; ch++) { >> + struct pl330_thread *thrd = &pl330->channels[ch]; >> + >> + found = -1; > > found can be uninitialized if we skip this for, which should not be an > issue as chans> 0! >
Exactly. Thanks, 'found' should be changed to for-loop local variable.
>> + for (pr = 0; pr < pchs; pr++) { >> + struct dma_pl330_chan *pch = &pl330->peripherals[pr]; >> + >> + if (!pch->thread || thrd->id != pch->thread->id) >> + continue; >> + >> + found = pr; >> + } >> + >> + seq_printf(s, "%d\t\t", thrd->id); >> + if (found == -1) >> + seq_puts(s, "--\n"); >> + else >> + seq_printf(s, "%d\n", found); >> + } >> + >> + return 0; >> +} >> + >> +DEFINE_SHOW_ATTRIBUTE(pl330_debugfs); >> + >> +static inline void init_pl330_debugfs(struct pl330_dmac *pl330) >> +{ >> + debugfs_create_file(dev_name(pl330->ddma.dev), >> + S_IFREG | S_IRUGO, NULL, pl330, > > are we not supposed to use octal permissions? > >> + &pl330_debugfs_fops); >> +} >> +#else >> +static inline void init_pl330_debugfs(struct pl330_dmac *pl330) >> +{ >> +} >> +#endif >> + >> /* >> * Runtime PM callbacks are provided by amba/bus.c driver. >> * >> @@ -3082,6 +3132,7 @@ pl330_probe(struct amba_device *adev, const struct amba_id *id) >> dev_err(&adev->dev, "unable to set the seg size\n"); >> >> >> + init_pl330_debugfs(pl330); >> dev_info(&adev->dev, >> "Loaded driver for PL330 DMAC-%x\n", adev->periphid); >> dev_info(&adev->dev, >> -- >> 2.20.1 >
Best Regards, Katsuhiro Suzuki
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