[PATCH v2] ARM: EDMA: Fix clearing of unused list for DT DMA resources
From: Sekhar Nori <hidden>
Date: 2013-07-29 07:02:13
Also in:
linux-mmc, linux-omap, lkml
On Monday 22 July 2013 11:29 PM, Joel Fernandes wrote:
HWMOD removal for MMC is breaking edma_start as the events are being manually triggered due to unused channel list not being clear, Thanks to Balaji TK for finding this issue.
So, Reported-by: Balaji T K [off-list ref] ?
quoted hunk ↗ jump to hunk
This patch fixes the issue, by reading the "dmas" property from the DT node if it exists and clearing the bits in the unused channel list. Cc: Balaji T K <redacted> Cc: Pantel Antoniou <redacted> Signed-off-by: Joel Fernandes <redacted> --- v2 changes: Fixed compiler warning arch/arm/common/edma.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-)diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c index a432e6c..765d578 100644 --- a/arch/arm/common/edma.c +++ b/arch/arm/common/edma.c@@ -561,14 +561,29 @@ static int reserve_contiguous_slots(int ctlr, unsigned int id, static int prepare_unused_channel_list(struct device *dev, void *data) { struct platform_device *pdev = to_platform_device(dev); - int i, ctlr; - - for (i = 0; i < pdev->num_resources; i++) { - if ((pdev->resource[i].flags & IORESOURCE_DMA) && - (int)pdev->resource[i].start >= 0) { - ctlr = EDMA_CTLR(pdev->resource[i].start); - clear_bit(EDMA_CHAN_SLOT(pdev->resource[i].start), - edma_cc[ctlr]->edma_unused); + int i = 0, ctlr; + u32 dma_chan; + const __be32 *dma_chan_p; + struct property *prop; + + if (dev->of_node) { + of_property_for_each_u32(dev->of_node, "dmas", prop, \ + dma_chan_p, dma_chan) { + if (i++ & 1) { + ctlr = EDMA_CTLR(dma_chan); + clear_bit(EDMA_CHAN_SLOT(dma_chan), + edma_cc[ctlr]->edma_unused); + }
I think it will be cleaner if you use of_property_count_strings() on dma-names to get the count of DMA channels for this device and then use of_parse_phandle_with_args() to get access to the args. Honestly, I have not used these APIs myself, so if this doesn?t work the way I think it should then let me know and I will try to do some experiments myself. The current way of skipping over even fields really depends on #dma-cells for EDMA to be 1. That in itself is not such a bad assumption, but if you have APIs which already take care of this for you, why not use them?
+ }
+ } else {
+ for (; i < pdev->num_resources; i++) {
+ if ((pdev->resource[i].flags & IORESOURCE_DMA) &&
+ (int)pdev->resource[i].start >= 0) {
+ ctlr = EDMA_CTLR(pdev->resource[i].start);
+ clear_bit(EDMA_CHAN_SLOT(
+ pdev->resource[i].start),
+ edma_cc[ctlr]->edma_unused);
+ }So there is very little in common between OF and non-OF versions of this function. Why not have two different versions of this function for the two cases? The OF version can reside under the CONFIG_OF conditional already in use in the file. This will also save you the ugly line breaks you had to resort to due to too deep indentation. Thanks, Sekhar