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

From: [email-masked] (Eric Bénard)
Date: Mon, 27 Aug 2012 16:30:06 +0200

Hi Greg, Hi Fabio,

this patch went into 3.4.10 as commit
9ea2c02bafe276e97b592a046ac733610a6d57fd
which seems wrong as devm_clk_get seems to be added in linux-3.5 so
compiling a 3.4.10 kernel with imx-dma enabled now leads :

drivers/dma/imx-dma.c: In function 'imxdma_probe':
drivers/dma/imx-dma.c:980: error: implicit declaration of function
'devm_clk_get'
drivers/dma/imx-dma.c:980: warning: assignment makes pointer from
integer without a cast
drivers/dma/imx-dma.c:986: warning: assignment makes pointer from
integer without a cast

Reverting 9ea2c02bafe276e97b592a046ac733610a6d57fd allows to get a
3.4.10 kernel running fine on an i.MX35.

Best regards
Eric

Le Tue, 3 Jul 2012 15:44:04-0300, Fabio Estevam
<[email-masked]> a ?crit :

> From: Fabio Estevam <[email-masked]>
> 
> 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 <[email-masked]>
> Signed-off-by: Fabio Estevam <[email-masked]>
> ---
>  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;
>  }