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Commit 50d64676 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Sarah Sharp
Browse files

xhci: Remove more doorbell-related reads 



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: default avatarMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
parent 7961acd7

drivers/usb/host/xhci-ring.c

+11 −16
Original line number Original line Diff line number Diff line
@@ -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 */

/* Ring the host controller doorbell after placing a command on the ring */

void xhci_ring_cmd_db(struct xhci_hcd *xhci)

void xhci_ring_cmd_db(struct xhci_hcd *xhci)

{

{

	u32 temp;



	xhci_dbg(xhci, "// Ding dong!\n");

	xhci_dbg(xhci, "// Ding dong!\n");

	temp = xhci_readl(xhci, &xhci->dba->doorbell[0]) & DB_MASK;

	xhci_writel(xhci, DB_VALUE_HOST, &xhci->dba->doorbell[0]);

	xhci_writel(xhci, temp | DB_TARGET_HOST, &xhci->dba->doorbell[0]);

	/* Flush PCI posted writes */

	/* Flush PCI posted writes */

	xhci_readl(xhci, &xhci->dba->doorbell[0]);

	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 ep_index,

		unsigned int stream_id)

		unsigned int stream_id)

{

{

	struct xhci_virt_ep *ep;

	unsigned int ep_state;

	u32 field;

	__u32 __iomem *db_addr = &xhci->dba->doorbell[slot_id];

	__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

	/* 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

	 * 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

	 * pointer command pending because the device can choose to start any

	 * stream once the endpoint is on the HW schedule.

	 * stream once the endpoint is on the HW schedule.

	 * FIXME - check all the stream rings for pending cancellations.

	 * FIXME - check all the stream rings for pending cancellations.

	 */

	 */

	if (!(ep_state & EP_HALT_PENDING) && !(ep_state & SET_DEQ_PENDING)

	if ((ep_state & EP_HALT_PENDING) || (ep_state & SET_DEQ_PENDING) ||

			&& !(ep_state & EP_HALTED)) {

	    (ep_state & EP_HALTED))

		field = xhci_readl(xhci, db_addr) & DB_MASK;

		return;

		field |= EPI_TO_DB(ep_index) | STREAM_ID_TO_DB(stream_id);

	xhci_writel(xhci, DB_VALUE(ep_index, stream_id), db_addr);

		xhci_writel(xhci, field, 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 */

/* Ring the doorbell for any rings with pending URBs */

drivers/usb/host/xhci.h

+6 −10
Original line number Original line Diff line number Diff line
@@ -436,22 +436,18 @@ struct xhci_run_regs { 
/**

/**

 * struct doorbell_array

 * struct doorbell_array

 *

 *

 * Bits  0 -  7: Endpoint target

 * Bits  8 - 15: RsvdZ

 * Bits 16 - 31: Stream ID

 *

 * Section 5.6

 * Section 5.6

 */

 */

struct xhci_doorbell_array {

struct xhci_doorbell_array {

	u32	doorbell[256];

	u32	doorbell[256];

};

};





#define	DB_TARGET_MASK		0xFFFFFF00

#define DB_VALUE(ep, stream)	((((ep) + 1) & 0xff) | ((stream) << 16))

#define	DB_STREAM_ID_MASK	0x0000FFFF

#define DB_VALUE_HOST		0x00000000

#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)







/**

/**

 * struct xhci_protocol_caps

 * struct xhci_protocol_caps