Re: [PATCH] ARM: rpi: fix reading of the EMMC clock for CONFIG_MMU

[Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>]

On Tue, Oct 15, 2013 at 07:38:23PM +0200, Andre Heider wrote:
> Add explicit flushing to prevent the 50MHz fallback.

Oops, I saw the message but didn't notice I introduced it.

The bcm2835_mci_get_emmc_clock() seems to use some mailbox system to get
the clock (from the graphics core?). We should probably convert this
into some generic code to access these bcm2835 mailboxes. Maybe U-Boot or
the kernel already provide code for it.

Anyway, applied this patch for now.

Sascha

> 
> Signed-off-by: Andre Heider <a.heider@xxxxxxxxx>
> ---
>  drivers/mci/mci-bcm2835.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mci/mci-bcm2835.c b/drivers/mci/mci-bcm2835.c
> index a0c364d..2ffdeec 100644
> --- a/drivers/mci/mci-bcm2835.c
> +++ b/drivers/mci/mci-bcm2835.c
> @@ -28,6 +28,7 @@
>   * Author: Wilhelm Lundgren <wilhelm.lundgren@xxxxxxxxxxxx>
>   */
>  
> +#include <asm/mmu.h>
>  #include <common.h>
>  #include <init.h>
>  #include <mci.h>
> @@ -471,7 +472,7 @@ int bcm2835_mci_reset(struct mci_host *mci, struct device_d *mci_dev)
>  static u32 bcm2835_mci_get_emmc_clock(struct msg_get_clock_rate *clk_data)
>  {
>  	u32 val;
> -	struct bcm2835_mbox_regs *regs =
> +	struct bcm2835_mbox_regs __iomem *regs =
>  			(struct bcm2835_mbox_regs *) BCM2835_MBOX_PHYSADDR;
>  
>  	/*Read out old msg*/
> @@ -489,6 +490,7 @@ static u32 bcm2835_mci_get_emmc_clock(struct msg_get_clock_rate *clk_data)
>  			break;
>  	}
>  	val = BCM2835_MBOX_PROP_CHAN + ((u32) &clk_data->hdr);
> +	dma_flush_range((u32)clk_data, (u32)clk_data + sizeof(*clk_data));
>  	writel(val, &regs->write);
>  
>  	while (true) {
> @@ -504,6 +506,9 @@ static u32 bcm2835_mci_get_emmc_clock(struct msg_get_clock_rate *clk_data)
>  		if ((val & 0x0F) == BCM2835_MBOX_PROP_CHAN)
>  			break;
>  	}
> +
> +	dma_inv_range((u32)clk_data, (u32)clk_data + sizeof(*clk_data));
> +
>  	if ((val & ~0x0F) == ((u32) &clk_data->hdr))
>  		if (clk_data->get_clock_rate.tag_hdr.val_len
>  				& BCM2835_MBOX_TAG_VAL_LEN_RESPONSE)
> -- 
> 1.8.3.2
> 
> 
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