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 <ma...@denx.de>
> Signed-off-by: Tom Rini <tr...@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
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