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xhci: Remove more doorbell-related reads

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The unused space in the doorbell is now marked as RsvdZ, not RsvdP, so
we can avoid reading the doorbell before writing it.

Update the doorbell-related defines to produce the entire doorbell value
from a single macro.  Document the doorbell format in a comment.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This commit is contained in:
Matthew Wilcox 2010-12-15 14:18:11 -05:00 committed by Sarah Sharp
parent 7961acd732
commit 50d64676d1
2 changed files with 17 additions and 26 deletions
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27
drivers/usb/host/xhci-ring.c
View file

@ -308,11 +308,8 @@ static int room_on_ring(struct xhci_hcd *xhci, struct xhci_ring *ring,
/* Ring the host controller doorbell after placing a command on the ring */
void xhci_ring_cmd_db(struct xhci_hcd *xhci)
{
u32 temp;
xhci_dbg(xhci, "// Ding dong!\n");
temp = xhci_readl(xhci, &xhci->dba->doorbell[0]) & DB_MASK;
xhci_writel(xhci, temp | DB_TARGET_HOST, &xhci->dba->doorbell[0]);
xhci_writel(xhci, DB_VALUE_HOST, &xhci->dba->doorbell[0]);
/* Flush PCI posted writes */
xhci_readl(xhci, &xhci->dba->doorbell[0]);
}
@ -322,26 +319,24 @@ void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
unsigned int ep_index,
unsigned int stream_id)
{
struct xhci_virt_ep *ep;
unsigned int ep_state;
u32 field;
__u32 __iomem *db_addr = &xhci->dba->doorbell[slot_id];
struct xhci_virt_ep *ep = &xhci->devs[slot_id]->eps[ep_index];
unsigned int ep_state = ep->ep_state;
ep = &xhci->devs[slot_id]->eps[ep_index];
ep_state = ep->ep_state;
/* Don't ring the doorbell for this endpoint if there are pending
* cancellations because the we don't want to interrupt processing.
* cancellations because we don't want to interrupt processing.
* We don't want to restart any stream rings if there's a set dequeue
* pointer command pending because the device can choose to start any
* stream once the endpoint is on the HW schedule.
* FIXME - check all the stream rings for pending cancellations.
*/
if (!(ep_state & EP_HALT_PENDING) && !(ep_state & SET_DEQ_PENDING)
&& !(ep_state & EP_HALTED)) {
field = xhci_readl(xhci, db_addr) & DB_MASK;
field |= EPI_TO_DB(ep_index) | STREAM_ID_TO_DB(stream_id);
xhci_writel(xhci, field, db_addr);
}
if ((ep_state & EP_HALT_PENDING) || (ep_state & SET_DEQ_PENDING) ||
(ep_state & EP_HALTED))
return;
xhci_writel(xhci, DB_VALUE(ep_index, stream_id), db_addr);
/* The CPU has better things to do at this point than wait for a
* write-posting flush. It'll get there soon enough.
*/
}
/* Ring the doorbell for any rings with pending URBs */

16
drivers/usb/host/xhci.h
View file

@ -436,22 +436,18 @@ struct xhci_run_regs {
/**
* struct doorbell_array
*
* Bits 0 - 7: Endpoint target
* Bits 8 - 15: RsvdZ
* Bits 16 - 31: Stream ID
*
* Section 5.6
*/
struct xhci_doorbell_array {
u32 doorbell[256];
};
#define DB_TARGET_MASK 0xFFFFFF00
#define DB_STREAM_ID_MASK 0x0000FFFF
#define DB_TARGET_HOST 0x0
#define DB_STREAM_ID_HOST 0x0
#define DB_MASK (0xff << 8)
/* Endpoint Target - bits 0:7 */
#define EPI_TO_DB(p) (((p) + 1) & 0xff)
#define STREAM_ID_TO_DB(p) (((p) & 0xffff) << 16)
#define DB_VALUE(ep, stream) ((((ep) + 1) & 0xff) | ((stream) << 16))
#define DB_VALUE_HOST 0x00000000
/**
* struct xhci_protocol_caps