[PATCH v3 2/9] usb: xhci: create one unified function to calculate TRB TD remainder.
Bin Meng
bmeng.cn at gmail.com
Tue Sep 8 07:41:55 CEST 2020
On Mon, Sep 7, 2020 at 3:14 PM Chunfeng Yun <chunfeng.yun at mediatek.com> wrote:
>
nits: please remove the ending period in the commit title
> 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.
>
> Porting from the Linux:
> c840d6ce772d("xhci: create one unified function to calculate TRB TD remainder.")
> 124c39371114("xhci: use boolean to indicate last trb in td remainder calculation")
>
> Signed-off-by: Chunfeng Yun <chunfeng.yun at mediatek.com>
> ---
> v2~v3: no changes
> ---
> drivers/usb/host/xhci-ring.c | 105 +++++++++++++++++++++----------------------
> include/usb/xhci.h | 2 +
> 2 files changed, 52 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 79bfc34..0f86b01 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -298,55 +298,52 @@ void xhci_queue_command(struct xhci_ctrl *ctrl, u8 *ptr, u32 slot_id,
> xhci_writel(&ctrl->dba->doorbell[0], DB_VALUE_HOST);
> }
>
> -/**
> - * 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.
> +/*
> + * For xHCI 1.0 host controllers, TD size is the number of max packet sized
> + * packets remaining in the TD (*not* including this TRB).
> *
> - * @param remainder remaining packets to be sent
> - * @return remainder if remainder is less than max else max
> - */
> -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;
> -}
> -
> -/**
> - * Finds out the remanining packets to be sent
> + * Total TD packet count = total_packet_count =
> + * DIV_ROUND_UP(TD size in bytes / wMaxPacketSize)
> + *
> + * Packets transferred up to and including this TRB = packets_transferred =
> + * rounddown(total bytes transferred including this TRB / wMaxPacketSize)
> + *
> + * TD size = total_packet_count - packets_transferred
> *
> - * @param running_total total size sent so far
> + * 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.
> + *
> + * @param ctrl host controller data structure
> + * @param transferred total size sent so far
> * @param trb_buff_len length of the TRB Buffer
> - * @param total_packet_count total packet count
> - * @param maxpacketsize max packet size of current pipe
> - * @param num_trbs_left number of TRBs left to be processed
> - * @return 0 if running_total or trb_buff_len is 0, else remainder
> + * @param td_total_len total packet count
> + * @param maxp max packet size of current pipe
> + * @param more_trbs_coming indicate last trb in TD
> + * @return remainder
> */
> -static u32 xhci_v1_0_td_remainder(int running_total,
> - int trb_buff_len,
> - unsigned int total_packet_count,
> - int maxpacketsize,
> - unsigned int num_trbs_left)
> +static u32 xhci_td_remainder(struct xhci_ctrl *ctrl, int transferred,
> + int trb_buff_len, unsigned int td_total_len,
> + int maxp, bool more_trbs_coming)
> {
> - int packets_transferred;
> + u32 total_packet_count;
> +
> + if (ctrl->hci_version < 0x100)
> + return ((td_total_len - transferred) >> 10);
>
> /* One TRB with a zero-length data packet. */
> - if (num_trbs_left == 0 || (running_total == 0 && trb_buff_len == 0))
> + if (!more_trbs_coming || (transferred == 0 && trb_buff_len == 0) ||
> + trb_buff_len == td_total_len)
> return 0;
>
> - /*
> - * All the TRB queueing functions don't count the current TRB in
> - * running_total.
> - */
> - packets_transferred = (running_total + trb_buff_len) / maxpacketsize;
> + total_packet_count = DIV_ROUND_UP(td_total_len, maxp);
>
> - 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));
> }
>
> /**
> @@ -572,7 +569,7 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
> union xhci_trb *event;
>
> int running_total, trb_buff_len;
> - unsigned int total_packet_count;
> + bool more_trbs_coming = true;
> int maxpacketsize;
> u64 addr;
> int ret;
> @@ -636,8 +633,6 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
> running_total = 0;
> maxpacketsize = usb_maxpacket(udev, pipe);
>
> - total_packet_count = DIV_ROUND_UP(length, maxpacketsize);
> -
> /* How much data is in the first TRB? */
> /*
> * How much data is (potentially) left before the 64KB boundary?
> @@ -672,27 +667,24 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
> * Chain all the TRBs together; clear the chain bit in the last
> * TRB to indicate it's the last TRB in the chain.
> */
> - if (num_trbs > 1)
> + if (num_trbs > 1) {
> field |= TRB_CHAIN;
> - else
> + } else {
> field |= TRB_IOC;
> + more_trbs_coming = false;
> + }
>
> /* Only set interrupt on short packet for IN endpoints */
> if (usb_pipein(pipe))
> field |= TRB_ISP;
>
> /* Set the TRB length, TD size, and interrupter fields. */
> - if (ctrl->hci_version < 0x100)
> - remainder = xhci_td_remainder(length - running_total);
> - else
> - remainder = xhci_v1_0_td_remainder(running_total,
> - trb_buff_len,
> - total_packet_count,
> - maxpacketsize,
> - num_trbs - 1);
> + remainder = xhci_td_remainder(ctrl, running_total, trb_buff_len,
> + length, maxpacketsize,
> + more_trbs_coming);
>
> length_field = ((trb_buff_len & TRB_LEN_MASK) |
> - remainder |
> + TRB_TD_SIZE(remainder) |
> ((0 & TRB_INTR_TARGET_MASK) <<
> TRB_INTR_TARGET_SHIFT));
>
> @@ -764,6 +756,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
> struct xhci_virt_device *virt_dev = ctrl->devs[slot_id];
> struct xhci_ring *ep_ring;
> union xhci_trb *event;
> + u32 remainder;
>
> debug("req=%u (%#x), type=%u (%#x), value=%u (%#x), index=%u\n",
> req->request, req->request,
> @@ -866,12 +859,14 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
> else
> field = (TRB_DATA << TRB_TYPE_SHIFT);
>
> - length_field = (length & TRB_LEN_MASK) | xhci_td_remainder(length) |
> + remainder = xhci_td_remainder(ctrl, 0, length, length,
> + usb_maxpacket(udev, pipe), 1);
1 should be true
> + length_field = (length & TRB_LEN_MASK) | TRB_TD_SIZE(remainder) |
> ((0 & TRB_INTR_TARGET_MASK) << TRB_INTR_TARGET_SHIFT);
> debug("length_field = %d, length = %d,"
> "xhci_td_remainder(length) = %d , TRB_INTR_TARGET(0) = %d\n",
> length_field, (length & TRB_LEN_MASK),
> - xhci_td_remainder(length), 0);
> + TRB_TD_SIZE(remainder), 0);
>
> if (length > 0) {
> if (req->requesttype & USB_DIR_IN)
> diff --git a/include/usb/xhci.h b/include/usb/xhci.h
> index a3e5914..15926eb 100644
> --- a/include/usb/xhci.h
> +++ b/include/usb/xhci.h
> @@ -850,6 +850,8 @@ struct xhci_event_cmd {
> /* transfer_len bitmasks - bits 0:16 */
> #define TRB_LEN(p) ((p) & 0x1ffff)
> #define TRB_LEN_MASK (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_SHIFT (22)
> #define TRB_INTR_TARGET_MASK (0x3ff)
Otherwise,
Reviewed-by: Bin Meng <bmeng.cn at gmail.com>
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