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Message-ID: <1441944485.25974.8.camel@mhfsdcap03>
Date: Fri, 11 Sep 2015 12:08:05 +0800
From: chunfeng yun <chunfeng.yun@...iatek.com>
To: Mathias Nyman <mathias.nyman@...ux.intel.com>
CC: <linux-kernel@...r.kernel.org>, <linux-usb@...r.kernel.org>,
<gregkh@...uxfoundation.org>, <linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH] xhci: create one unified function to calculate TRB TD
remainder.
Hi,
On Tue, 2015-09-08 at 14:09 +0300, Mathias Nyman wrote:
> xhci versions 1.0 and later report the untransferred data remaining in a
> TD a bit differently than older hosts.
>
> We used to have separate functions for these, and needed to check host
> version before calling the right function.
>
> Now Mediatek host has an additional quirk on how it uses the TD Size
> field for remaining data. To prevent yet another function for calculating
> remainder we instead want to make one quirk friendly unified function.
>
> Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
> ---
> drivers/usb/host/xhci-ring.c | 106 ++++++++++++++++++-------------------------
> drivers/usb/host/xhci.h | 2 +
> 2 files changed, 46 insertions(+), 62 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index a47a1e8..57f40a1 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -3020,21 +3020,6 @@ int xhci_queue_intr_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> }
>
> /*
> - * The TD size is the number of bytes remaining in the TD (including this TRB),
> - * right shifted by 10.
> - * It must fit in bits 21:17, so it can't be bigger than 31.
> - */
> -static u32 xhci_td_remainder(unsigned int remainder)
> -{
> - u32 max = (1 << (21 - 17 + 1)) - 1;
> -
> - if ((remainder >> 10) >= max)
> - return max << 17;
> - else
> - return (remainder >> 10) << 17;
> -}
> -
> -/*
> * For xHCI 1.0 host controllers, TD size is the number of max packet sized
> * packets remaining in the TD (*not* including this TRB).
> *
> @@ -3046,30 +3031,36 @@ static u32 xhci_td_remainder(unsigned int remainder)
> *
> * TD size = total_packet_count - packets_transferred
> *
> - * It must fit in bits 21:17, so it can't be bigger than 31.
> + * For xHCI 0.96 and older, TD size field should be the remaining bytes
> + * including this TRB, right shifted by 10
> + *
> + * For all hosts it must fit in bits 21:17, so it can't be bigger than 31.
> + * This is taken care of in the TRB_TD_SIZE() macro
> + *
> * The last TRB in a TD must have the TD size set to zero.
> */
> -static u32 xhci_v1_0_td_remainder(int running_total, int trb_buff_len,
> - unsigned int total_packet_count, struct urb *urb,
> - unsigned int num_trbs_left)
> +static u32 xhci_td_remainder(struct xhci_hcd *xhci, int transferred,
> + int trb_buff_len, unsigned int td_total_len,
> + struct urb *urb, unsigned int num_trbs_left)
> {
> - int packets_transferred;
> + u32 maxp, total_packet_count;
> +
> + if (xhci->hci_version < 0x100)
> + return ((td_total_len - transferred) >> 10);
> +
> + maxp = GET_MAX_PACKET(usb_endpoint_maxp(&urb->ep->desc));
> + total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>
> /* One TRB with a zero-length data packet. */
> - if (num_trbs_left == 0 || (running_total == 0 && trb_buff_len == 0))
> + if (num_trbs_left == 0 || (transferred == 0 && trb_buff_len == 0) ||
> + trb_buff_len == td_total_len)
> return 0;
>
I think when trb_buff_len == td_total_len, the TD only needs one trb, so
num_trbs_left will equal to 0; that means no need add this condition.
> - /* All the TRB queueing functions don't count the current TRB in
> - * running_total.
> - */
> - packets_transferred = (running_total + trb_buff_len) /
> - GET_MAX_PACKET(usb_endpoint_maxp(&urb->ep->desc));
> -
> - if ((total_packet_count - packets_transferred) > 31)
> - return 31 << 17;
> - return (total_packet_count - packets_transferred) << 17;
> + /* Queueing functions don't count the current TRB into transferred */
> + return (total_packet_count - ((transferred + trb_buff_len) / maxp));
> }
>
> +
> static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> struct urb *urb, int slot_id, unsigned int ep_index)
> {
> @@ -3191,17 +3182,12 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> }
>
> /* Set the TRB length, TD size, and interrupter fields. */
> - if (xhci->hci_version < 0x100) {
> - remainder = xhci_td_remainder(
> - urb->transfer_buffer_length -
> - running_total);
> - } else {
> - remainder = xhci_v1_0_td_remainder(running_total,
> - trb_buff_len, total_packet_count, urb,
> - num_trbs - 1);
> - }
> + remainder = xhci_td_remainder(xhci, running_total, trb_buff_len,
> + urb->transfer_buffer_length,
> + urb, num_trbs - 1);
> +
> length_field = TRB_LEN(trb_buff_len) |
> - remainder |
> + TRB_TD_SIZE(remainder) |
> TRB_INTR_TARGET(0);
>
> if (num_trbs > 1)
> @@ -3364,17 +3350,12 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> field |= TRB_ISP;
>
> /* Set the TRB length, TD size, and interrupter fields. */
> - if (xhci->hci_version < 0x100) {
> - remainder = xhci_td_remainder(
> - urb->transfer_buffer_length -
> - running_total);
> - } else {
> - remainder = xhci_v1_0_td_remainder(running_total,
> - trb_buff_len, total_packet_count, urb,
> - num_trbs - 1);
> - }
> + remainder = xhci_td_remainder(xhci, running_total, trb_buff_len,
> + urb->transfer_buffer_length,
> + urb, num_trbs - 1);
> +
> length_field = TRB_LEN(trb_buff_len) |
> - remainder |
> + TRB_TD_SIZE(remainder) |
> TRB_INTR_TARGET(0);
>
> if (num_trbs > 1)
> @@ -3412,7 +3393,7 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> struct usb_ctrlrequest *setup;
> struct xhci_generic_trb *start_trb;
> int start_cycle;
> - u32 field, length_field;
> + u32 field, length_field, remainder;
> struct urb_priv *urb_priv;
> struct xhci_td *td;
>
> @@ -3485,9 +3466,15 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> else
> field = TRB_TYPE(TRB_DATA);
>
> + remainder = xhci_td_remainder(xhci, 0,
> + urb->transfer_buffer_length,
> + urb->transfer_buffer_length,
> + urb, 1);
> +
> length_field = TRB_LEN(urb->transfer_buffer_length) |
> - xhci_td_remainder(urb->transfer_buffer_length) |
> + TRB_TD_SIZE(remainder) |
> TRB_INTR_TARGET(0);
> +
> if (urb->transfer_buffer_length > 0) {
> if (setup->bRequestType & USB_DIR_IN)
> field |= TRB_DIR_IN;
> @@ -3816,17 +3803,12 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> trb_buff_len = td_remain_len;
>
> /* Set the TRB length, TD size, & interrupter fields. */
> - if (xhci->hci_version < 0x100) {
> - remainder = xhci_td_remainder(
> - td_len - running_total);
> - } else {
> - remainder = xhci_v1_0_td_remainder(
> - running_total, trb_buff_len,
> - total_packet_count, urb,
> - (trbs_per_td - j - 1));
> - }
> + remainder = xhci_td_remainder(xhci, running_total,
> + trb_buff_len, td_len,
> + urb, trbs_per_td - j - 1);
> +
> length_field = TRB_LEN(trb_buff_len) |
> - remainder |
> + TRB_TD_SIZE(remainder) |
> TRB_INTR_TARGET(0);
>
> queue_trb(xhci, ep_ring, more_trbs_coming,
> diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
> index dbda41e..ea8b904 100644
> --- a/drivers/usb/host/xhci.h
> +++ b/drivers/usb/host/xhci.h
> @@ -1136,6 +1136,8 @@ enum xhci_setup_dev {
> /* Normal TRB fields */
> /* transfer_len bitmasks - bits 0:16 */
> #define TRB_LEN(p) ((p) & 0x1ffff)
> +/* TD Size, packets remaining in this TD, bits 21:17 (5 bits, so max 31) */
> +#define TRB_TD_SIZE(p) (min((p), (u32)31) << 17)
> /* Interrupter Target - which MSI-X vector to target the completion event at */
> #define TRB_INTR_TARGET(p) (((p) & 0x3ff) << 22)
> #define GET_INTR_TARGET(p) (((p) >> 22) & 0x3ff)
--
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