ARM: mx3: Setup AIPS registers

It was observed on a mx31pdk board that audio playback only worked when the bootloader was Redboot, and 
did not work when U-boot was used. 

Comparing the sources of these bootloaders showed that the AIPS registers were not setup in U-boot.

Instead of relying on the bootloader to setup the AIPS registers, do it in the kernel so that audio
playback can work independantly of the bootloader being used.

Copied the AIPS settings from Redboot to the kernel.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
 arch/arm/mach-imx/cpu-imx31.c |   32 ++++++++++++++++++++++++++++++++
 1 files changed, 32 insertions(+), 0 deletions(-)

On Tue, Feb 28, 2012 at 12:15:01AM -0300, Fabio Estevam wrote:
> It was observed on a mx31pdk board that audio playback only worked when the bootloader was Redboot, and 
> did not work when U-boot was used. 
> 
> Comparing the sources of these bootloaders showed that the AIPS registers were not setup in U-boot.
> 
> Instead of relying on the bootloader to setup the AIPS registers, do it in the kernel so that audio
> playback can work independantly of the bootloader being used.
> 
> Copied the AIPS settings from Redboot to the kernel.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
>  arch/arm/mach-imx/cpu-imx31.c |   32 ++++++++++++++++++++++++++++++++
>  1 files changed, 32 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/cpu-imx31.c b/arch/arm/mach-imx/cpu-imx31.c
> index 3f2345f..c309d51 100644
> --- a/arch/arm/mach-imx/cpu-imx31.c
> +++ b/arch/arm/mach-imx/cpu-imx31.c
> @@ -60,3 +60,35 @@ int mx31_revision(void)
>  	return mx31_cpu_rev;
>  }
>  EXPORT_SYMBOL(mx31_revision);
> +
> +static void __init imx_set_aips(void __iomem *base)
> +{
> +	unsigned int reg;
> +/*
> + * Set all MPROTx to be non-bufferable, trusted for R/W,
> + * not forced to user-mode.
> + */
> +	__raw_writel(0x77777777, base + 0x0);
> +	__raw_writel(0x77777777, base + 0x4);
> +
> +/*
> + * Clear the on and off peripheral modules Supervisor Protect bit
> + * for SDMA to access them. Did not change the AIPS control registers
> + * (offset 0x20) access type
> + */
> +	__raw_writel(0x0, base + 0x40);
> +	__raw_writel(0x0, base + 0x44);
> +	__raw_writel(0x0, base + 0x48);
> +	__raw_writel(0x0, base + 0x4C);
> +	reg = __raw_readl(base + 0x50) & 0x00FFFFFF;
> +	__raw_writel(reg, base + 0x50);
> +}
> +
> +static int __init post_cpu_init(void)
> +{
> +	imx_set_aips(MX31_IO_ADDRESS(MX31_AIPS1_BASE_ADDR));
> +	imx_set_aips(MX31_IO_ADDRESS(MX31_AIPS2_BASE_ADDR));
> +
> +	return 0;
> +}
> +postcore_initcall(post_cpu_init);

Nah, you don't want this code to run on all SoCs compiled into
the kernel, do you?

BTW the AIPS setup looks useful for other SoCs aswell, maybe
imx_set_aips should go to a more general place?

Sascha

On 28.02.2012 04:15, Fabio Estevam wrote:
> It was observed on a mx31pdk board that audio playback only worked when the bootloader was Redboot, and 
> did not work when U-boot was used. 
> 
> Comparing the sources of these bootloaders showed that the AIPS registers were not setup in U-boot.
> 
> Instead of relying on the bootloader to setup the AIPS registers, do it in the kernel so that audio
> playback can work independantly of the bootloader being used.
> 
> Copied the AIPS settings from Redboot to the kernel.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
>  arch/arm/mach-imx/cpu-imx31.c |   32 ++++++++++++++++++++++++++++++++
>  1 files changed, 32 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/cpu-imx31.c b/arch/arm/mach-imx/cpu-imx31.c
> index 3f2345f..c309d51 100644
> --- a/arch/arm/mach-imx/cpu-imx31.c
> +++ b/arch/arm/mach-imx/cpu-imx31.c
> @@ -60,3 +60,35 @@ int mx31_revision(void)
>  	return mx31_cpu_rev;
>  }
>  EXPORT_SYMBOL(mx31_revision);
> +
> +static void __init imx_set_aips(void __iomem *base)
> +{
> +	unsigned int reg;
> +/*
> + * Set all MPROTx to be non-bufferable, trusted for R/W,
> + * not forced to user-mode.
> + */
> +	__raw_writel(0x77777777, base + 0x0);
> +	__raw_writel(0x77777777, base + 0x4);
> +
> +/*
> + * Clear the on and off peripheral modules Supervisor Protect bit
> + * for SDMA to access them. Did not change the AIPS control registers
> + * (offset 0x20) access type
> + */
> +	__raw_writel(0x0, base + 0x40);
> +	__raw_writel(0x0, base + 0x44);
> +	__raw_writel(0x0, base + 0x48);
> +	__raw_writel(0x0, base + 0x4C);
> +	reg = __raw_readl(base + 0x50) & 0x00FFFFFF;
> +	__raw_writel(reg, base + 0x50);
> +}
> +
> +static int __init post_cpu_init(void)
> +{
> +	imx_set_aips(MX31_IO_ADDRESS(MX31_AIPS1_BASE_ADDR));
> +	imx_set_aips(MX31_IO_ADDRESS(MX31_AIPS2_BASE_ADDR));
> +
> +	return 0;
> +}
> +postcore_initcall(post_cpu_init);

Hmm, I'm not totally sure if we talk about the same thing, but at least 
it looks somehow similar:

For i.MX6 we have the following patch in U-Boot:

http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=commitdiff;h=f2f7745825ee5f6bae5b480c8e9c6641a7ffa73b

If this is the same, maybe we should discuss about (a) where to do this 
(boot loader or kernel) and (b) if we could create a common function for 
this?

Best regards

Dirk