[U-Boot] [PATCH v3 2/6] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment

[Marek Vasut <marex@denx.de>]

Dear Tom Rini,

> The USB spec says that 32 bytes is the minimum required alignment.
> However on some platforms we have a larger minimum requirement for cache
> coherency.  In those cases, use that value rather than the USB spec
> minimum.  We add a cpp check to <usb.h> to define USB_DMA_MINALIGN and
> make use of it in ehci-hcd.c and musb_core.h.  We cannot use MAX() here
> as we are not allowed to have tests inside of align(...).
> 
> Cc: Marek Vasut <marex@denx.de>
> Signed-off-by: Tom Rini <trini@ti.com>
> 
> --
> Changes in v2:
> - Move test to <usb.h>, expand comment.
> ---
>  drivers/usb/host/ehci-hcd.c  |   13 +++++++------
>  drivers/usb/musb/musb_core.h |    2 +-
>  include/usb.h                |   10 ++++++++++
>  3 files changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
> index 04300be..5a86117 100644
> --- a/drivers/usb/host/ehci-hcd.c
> +++ b/drivers/usb/host/ehci-hcd.c
> @@ -29,12 +29,13 @@
> 
>  #include "ehci.h"
> 
> -int rootdev;
> -struct ehci_hccr *hccr;	/* R/O registers, not need for volatile */
> -volatile struct ehci_hcor *hcor;
> +int rootdev __attribute__((aligned(USB_DMA_MINALIGN)));
> +/* R/O registers, not need for volatile */
> +struct ehci_hccr *hccr __attribute__((aligned(USB_DMA_MINALIGN)));
> +volatile struct ehci_hcor *hcor
> __attribute__((aligned(USB_DMA_MINALIGN)));

^ these need to be aligned too?

> 
>  static uint16_t portreset;
> -static struct QH qh_list __attribute__((aligned(32)));
> +static struct QH qh_list __attribute__((aligned(USB_DMA_MINALIGN)));
> 
>  static struct descriptor {
>  	struct usb_hub_descriptor hub;
> @@ -207,8 +208,8 @@ static int
>  ehci_submit_async(struct usb_device *dev, unsigned long pipe, void
> *buffer, int length, struct devrequest *req)
>  {
> -	static struct QH qh __attribute__((aligned(32)));
> -	static struct qTD qtd[3] __attribute__((aligned (32)));
> +	static struct QH qh __attribute__((aligned(USB_DMA_MINALIGN)));
> +	static struct qTD qtd[3] __attribute__((aligned(USB_DMA_MINALIGN)));
>  	int qtd_counter = 0;
> 
>  	volatile struct qTD *vtd;
> diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
> index a8adcce..e914369 100644
> --- a/drivers/usb/musb/musb_core.h
> +++ b/drivers/usb/musb/musb_core.h
> @@ -145,7 +145,7 @@ struct musb_regs {
>  		struct musb_epN_regs epN;
>  	} ep[16];
> 
> -} __attribute__((packed, aligned(32)));
> +} __attribute__((packed, aligned(USB_DMA_MINALIGN)));
>  #endif
> 
>  /*
> diff --git a/include/usb.h b/include/usb.h
> index 6da91e7..ba3d169 100644
> --- a/include/usb.h
> +++ b/include/usb.h
> @@ -29,6 +29,16 @@
>  #include <usb_defs.h>
>  #include <usbdescriptors.h>
> 
> +/*
> + * The EHCI spec says that we must align to at least 32 bytes.  However,
> + * some platforms require larger alignment.
> + */
> +#if ARCH_DMA_MINALIGN > 32
> +#define USB_DMA_MINALIGN	ARCH_DMA_MINALIGN
> +#else
> +#define USB_DMA_MINALIGN	32
> +#endif
> +
>  /* Everything is aribtrary */
>  #define USB_ALTSETTINGALLOC		4
>  #define USB_MAXALTSETTING		128	/* Hard limit */

Best regards,
Marek Vasut