[PATCH] dma: imx-dma: Fix kernel crash due to missing clock conversion

[fabio.estevam@freescale.com (Fabio Estevam)]

From: Fabio Estevam <festevam@gmail.com>

With the new i.MX clock infrastructure we need to request the dma clocks
seperately: ahb and ipg clocks.

This fixes the following kernel crash and make audio to be functional again:

root at freescale /home$ aplay audio48k16S.wav 
Playing WAVE 'audio48k16S.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c7b74000
[00000000] *pgd=a7bb5831, *pte=00000000, *ppte=00000000
Internal error: Oops: 17 [#1] PREEMPT ARM
Modules linked in:
CPU: 0    Not tainted  (3.5.0-rc5-next-20120702-00007-g3028b64 #1128)
PC is at snd_dmaengine_pcm_get_chan+0x8/0x10
LR is at snd_imx_pcm_hw_params+0x18/0xdc
pc : [<c02d3cf8>]    lr : [<c02e95ec>]    psr: a0000013
sp : c7b45e30  ip : ffffffff  fp : c7ae58e0
r10: 00000000  r9 : c7ae981c  r8 : c7b88800
r7 : c7ae5a60  r6 : c7ae5b20  r5 : c7ae9810  r4 : c7afa060
r3 : 00000000  r2 : 00000001  r1 : c7b88800  r0 : c7afa060
Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
Control: 0005317f  Table: a7b74000  DAC: 00000015
Process aplay (pid: 701, stack limit = 0xc7b44270)
Stack: (0xc7b45e30 to 0xc7b46000)
5e20:                                     00100000 00000029 c7b88800 c02db870
5e40: c7ae5a60 c02d4594 00000010 01ae5a60 c7ae5a60 c7ae9810 c7ae9810 c7afa060
5e60: c7ae5b20 c7ae5a60 c7b88800 c02e3ef0 c02e3e08 c7b1e400 c7afa060 c7b88800
5e80: 00000000 c0014da8 c7b44000 00000000 bec566ac c02cd400 c7afa060 c7afa060
5ea0: bec56800 c7b88800 c0014da8 c02cdd7c c04ee710 c04ee7b8 00000003 c005fc74
5ec0: 00000000 7fffffff c7b45f00 c7afa060 c7b67420 c7ba3070 00000004 c0014da8
5ee0: c7b44000 00000000 bec566ac c02ced88 c04e95f8 b6f5ab04 c7b45fb0 0145a468
5f00: 0145a600 bec566bc bec56800 c7b67420 c7ba3070 c00d499c c7b45f18 c7b45f18
5f20: 0000001a 00000004 00000001 c7b44000 c0527f40 00000009 00000008 00000000
5f40: c7b44000 c002c9ec 00000001 c04f0ab0 c04ebec0 00000101 00000000 0000000a
5f60: 60000093 c7b67420 bec56800 c25c4111 00000004 c0014da8 c7b44000 00000000
5f80: bec566ac c00d4f38 b6ffb658 00000000 c0522d80 0145a468 b6fd5000 0145a418
5fa0: 00000036 c0014c00 0145a468 b6fd5000 00000004 c25c4111 bec56800 00020001
5fc0: 0145a468 b6fd5000 0145a418 00000036 0145a468 0145a600 bec566bc bec566ac
5fe0: 0145a468 bec56388 b6f65ce4 b6dcebec 20000010 00000004 00000000 00000000
[<c02d3cf8>] (snd_dmaengine_pcm_get_chan+0x8/0x10) from [<c02e95ec>] (snd_imx_pcm_hw_params+0x18/0xdc)
[<c02e95ec>] (snd_imx_pcm_hw_params+0x18/0xdc) from [<c02e3ef0>] (soc_pcm_hw_params+0xe8/0x1f0)
[<c02e3ef0>] (soc_pcm_hw_params+0xe8/0x1f0) from [<c02cd400>] (snd_pcm_hw_params+0x124/0x474)
[<c02cd400>] (snd_pcm_hw_params+0x124/0x474) from [<c02cdd7c>] (snd_pcm_common_ioctl1+0x4b4/0xf74)
[<c02cdd7c>] (snd_pcm_common_ioctl1+0x4b4/0xf74) from [<c02ced88>] (snd_pcm_playback_ioctl1+0x30/0x510)
[<c02ced88>] (snd_pcm_playback_ioctl1+0x30/0x510) from [<c00d499c>] (do_vfs_ioctl+0x80/0x5e4)
[<c00d499c>] (do_vfs_ioctl+0x80/0x5e4) from [<c00d4f38>] (sys_ioctl+0x38/0x60)
[<c00d4f38>] (sys_ioctl+0x38/0x60) from [<c0014c00>] (ret_fast_syscall+0x0/0x2c)
Code: e593000c e12fff1e e59030a0 e59330bc (e5930000) 
---[ end trace fa518c8ba3a74e97 ]--

Reported-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
 drivers/dma/imx-dma.c |   36 +++++++++++++++++++++++++-----------
 1 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/dma/imx-dma.c b/drivers/dma/imx-dma.c
index fcfeb3c..5084975 100644
--- a/drivers/dma/imx-dma.c
+++ b/drivers/dma/imx-dma.c
@@ -172,7 +172,8 @@ struct imxdma_engine {
 	struct device_dma_parameters	dma_parms;
 	struct dma_device		dma_device;
 	void __iomem			*base;
-	struct clk			*dma_clk;
+	struct clk			*dma_ahb;
+	struct clk			*dma_ipg;
 	spinlock_t			lock;
 	struct imx_dma_2d_config	slots_2d[IMX_DMA_2D_SLOTS];
 	struct imxdma_channel		channel[IMX_DMA_CHANNELS];
@@ -976,10 +977,20 @@ static int __init imxdma_probe(struct platform_device *pdev)
 		return 0;
 	}
 
-	imxdma->dma_clk = clk_get(NULL, "dma");
-	if (IS_ERR(imxdma->dma_clk))
-		return PTR_ERR(imxdma->dma_clk);
-	clk_enable(imxdma->dma_clk);
+	imxdma->dma_ipg = devm_clk_get(&pdev->dev, "ipg");
+	if (IS_ERR(imxdma->dma_ipg)) {
+		ret = PTR_ERR(imxdma->dma_ipg);
+		goto err_clk;
+	}
+
+	imxdma->dma_ahb = devm_clk_get(&pdev->dev, "ahb");
+	if (IS_ERR(imxdma->dma_ahb)) {
+		ret = PTR_ERR(imxdma->dma_ahb);
+		goto err_clk;
+	}
+
+	clk_prepare_enable(imxdma->dma_ipg);
+	clk_prepare_enable(imxdma->dma_ahb);
 
 	/* reset DMA module */
 	imx_dmav1_writel(imxdma, DCR_DRST, DMA_DCR);
@@ -988,16 +999,14 @@ static int __init imxdma_probe(struct platform_device *pdev)
 		ret = request_irq(MX1_DMA_INT, dma_irq_handler, 0, "DMA", imxdma);
 		if (ret) {
 			dev_warn(imxdma->dev, "Can't register IRQ for DMA\n");
-			kfree(imxdma);
-			return ret;
+			goto err_enable;
 		}
 
 		ret = request_irq(MX1_DMA_ERR, imxdma_err_handler, 0, "DMA", imxdma);
 		if (ret) {
 			dev_warn(imxdma->dev, "Can't register ERRIRQ for DMA\n");
 			free_irq(MX1_DMA_INT, NULL);
-			kfree(imxdma);
-			return ret;
+			goto err_enable;
 		}
 	}
 
@@ -1094,7 +1103,10 @@ err_init:
 		free_irq(MX1_DMA_INT, NULL);
 		free_irq(MX1_DMA_ERR, NULL);
 	}
-
+err_enable:
+	clk_disable_unprepare(imxdma->dma_ipg);
+	clk_disable_unprepare(imxdma->dma_ahb);
+err_clk:
 	kfree(imxdma);
 	return ret;
 }
@@ -1114,7 +1126,9 @@ static int __exit imxdma_remove(struct platform_device *pdev)
 		free_irq(MX1_DMA_ERR, NULL);
 	}
 
-        kfree(imxdma);
+	clk_disable_unprepare(imxdma->dma_ipg);
+	clk_disable_unprepare(imxdma->dma_ahb);
+	kfree(imxdma);
 
         return 0;
 }
-- 
1.7.1