On Tue, 12 Aug 2014, Geert Uytterhoeven wrote:
> I tried a few things to fix this, but I'm not so sure what's the best solution:
>
> Works:
> - Calling clk_enable(dmac->clk)/clk_disable(dmac->clk) before resp.
> after the call to rcar_dmac_init(). This also needs rcar_dmac.clk setup,
> cfr. the first version of the rcar-dmac driver.
It never hurts to send an actual patch...
>From 6f3288de9fe8f107896e65203d3c098989966870 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Date: Tue, 12 Aug 2014 14:24:45 +0200
Subject: [PATCH] [RFC] dmaengine: rcar-dmac: Fix reinitialization on resume
When resuming from s2ram on Koelsch ("echo mem > /sys/power/state" to
suspend, and press any of the SW3x to resume), DMAOR initialization fails:
rcar-dmac e6700000.dma-controller: DMAOR initialization failed.
dpm_run_callback(): platform_pm_resume+0x0/0x54 returns -5
PM: Device e6700000.dma-controller failed to resume: error -5
rcar-dmac e6720000.dma-controller: DMAOR initialization failed.
dpm_run_callback(): platform_pm_resume+0x0/0x54 returns -5
PM: Device e6720000.dma-controller failed to resume: error -5
(note that DMA still works after this)
This is due to rcar_dmac_resume() calling rcar_dmac_init() while the
device's clock is disabled.
Explicitly enable the clock before calling rcar_dmac_init() to fix this,
and disable the clock again afterwards.
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 0997322b70f8..334ddd3a37c0 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -10,6 +10,7 @@
* published by the Free Software Foundation.
*/
+#include <linux/clk.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/list.h>
@@ -155,6 +156,7 @@ struct rcar_dmac {
struct dma_device engine;
struct device *dev;
void __iomem *iomem;
+ struct clk *clk;
char *irqname;
unsigned int n_channels;
@@ -1282,8 +1284,16 @@ static int rcar_dmac_suspend(struct device *dev)
static int rcar_dmac_resume(struct device *dev)
{
struct rcar_dmac *dmac = dev_get_drvdata(dev);
+ int ret;
- return rcar_dmac_init(dmac);
+ ret = clk_enable(dmac->clk);
+ if (ret < 0)
+ return ret;
+
+ ret = rcar_dmac_init(dmac);
+
+ clk_disable(dmac->clk);
+ return ret;
}
#endif
@@ -1336,6 +1346,12 @@ static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
return ret;
}
+ dmac->clk = clk_get(&pdev->dev, "fck");
+ if (IS_ERR(dmac->clk)) {
+ dev_err(&pdev->dev, "unable to get fck clock\n");
+ return PTR_ERR(dmac->clk);
+ }
+
/*
* Initialize the DMA engine channel and add it to the DMA engine
* channels list.
--
1.9.1
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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