[PATCH] UHCI: use one QH per endpoint, not per URB
This patch (as623) changes the uhci-hcd driver to make it use one QH per
device endpoint, instead of a QH per URB as it does now. Numerous areas
of the code are affected by this. For example, the distinction between
"queued" URBs and non-"queued" URBs no longer exists; all URBs belong to
a queue and some just happen to be at the queue's head.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 8b4b887..7a9481c 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -28,8 +28,9 @@
#define USBSTS_USBINT 0x0001 /* Interrupt due to IOC */
#define USBSTS_ERROR 0x0002 /* Interrupt due to error */
#define USBSTS_RD 0x0004 /* Resume Detect */
-#define USBSTS_HSE 0x0008 /* Host System Error - basically PCI problems */
-#define USBSTS_HCPE 0x0010 /* Host Controller Process Error - the scripts were buggy */
+#define USBSTS_HSE 0x0008 /* Host System Error: PCI problems */
+#define USBSTS_HCPE 0x0010 /* Host Controller Process Error:
+ * the schedule is buggy */
#define USBSTS_HCH 0x0020 /* HC Halted */
/* Interrupt enable register */
@@ -47,7 +48,8 @@
/* USB port status and control registers */
#define USBPORTSC1 16
#define USBPORTSC2 18
-#define USBPORTSC_CCS 0x0001 /* Current Connect Status ("device present") */
+#define USBPORTSC_CCS 0x0001 /* Current Connect Status
+ * ("device present") */
#define USBPORTSC_CSC 0x0002 /* Connect Status Change */
#define USBPORTSC_PE 0x0004 /* Port Enable */
#define USBPORTSC_PEC 0x0008 /* Port Enable Change */
@@ -71,15 +73,16 @@
#define USBLEGSUP_RWC 0x8f00 /* the R/WC bits */
#define USBLEGSUP_RO 0x5040 /* R/O and reserved bits */
-#define UHCI_PTR_BITS cpu_to_le32(0x000F)
-#define UHCI_PTR_TERM cpu_to_le32(0x0001)
-#define UHCI_PTR_QH cpu_to_le32(0x0002)
-#define UHCI_PTR_DEPTH cpu_to_le32(0x0004)
-#define UHCI_PTR_BREADTH cpu_to_le32(0x0000)
+#define UHCI_PTR_BITS __constant_cpu_to_le32(0x000F)
+#define UHCI_PTR_TERM __constant_cpu_to_le32(0x0001)
+#define UHCI_PTR_QH __constant_cpu_to_le32(0x0002)
+#define UHCI_PTR_DEPTH __constant_cpu_to_le32(0x0004)
+#define UHCI_PTR_BREADTH __constant_cpu_to_le32(0x0000)
#define UHCI_NUMFRAMES 1024 /* in the frame list [array] */
#define UHCI_MAX_SOF_NUMBER 2047 /* in an SOF packet */
-#define CAN_SCHEDULE_FRAMES 1000 /* how far future frames can be scheduled */
+#define CAN_SCHEDULE_FRAMES 1000 /* how far in the future frames
+ * can be scheduled */
/*
@@ -87,38 +90,54 @@
*/
/*
- * One role of a QH is to hold a queue of TDs for some endpoint. Each QH is
- * used with one URB, and qh->element (updated by the HC) is either:
- * - the next unprocessed TD for the URB, or
- * - UHCI_PTR_TERM (when there's no more traffic for this endpoint), or
- * - the QH for the next URB queued to the same endpoint.
+ * One role of a QH is to hold a queue of TDs for some endpoint. One QH goes
+ * with each endpoint, and qh->element (updated by the HC) is either:
+ * - the next unprocessed TD in the endpoint's queue, or
+ * - UHCI_PTR_TERM (when there's no more traffic for this endpoint).
*
* The other role of a QH is to serve as a "skeleton" framelist entry, so we
* can easily splice a QH for some endpoint into the schedule at the right
* place. Then qh->element is UHCI_PTR_TERM.
*
- * In the frame list, qh->link maintains a list of QHs seen by the HC:
+ * In the schedule, qh->link maintains a list of QHs seen by the HC:
* skel1 --> ep1-qh --> ep2-qh --> ... --> skel2 --> ...
+ *
+ * qh->node is the software equivalent of qh->link. The differences
+ * are that the software list is doubly-linked and QHs in the UNLINKING
+ * state are on the software list but not the hardware schedule.
+ *
+ * For bookkeeping purposes we maintain QHs even for Isochronous endpoints,
+ * but they never get added to the hardware schedule.
*/
+#define QH_STATE_IDLE 1 /* QH is not being used */
+#define QH_STATE_UNLINKING 2 /* QH has been removed from the
+ * schedule but the hardware may
+ * still be using it */
+#define QH_STATE_ACTIVE 3 /* QH is on the schedule */
+
struct uhci_qh {
/* Hardware fields */
- __le32 link; /* Next queue */
- __le32 element; /* Queue element pointer */
+ __le32 link; /* Next QH in the schedule */
+ __le32 element; /* Queue element (TD) pointer */
/* Software fields */
dma_addr_t dma_handle;
- struct urb_priv *urbp;
+ struct list_head node; /* Node in the list of QHs */
+ struct usb_host_endpoint *hep; /* Endpoint information */
+ struct usb_device *udev;
+ struct list_head queue; /* Queue of urbps for this QH */
+ struct uhci_qh *skel; /* Skeleton for this QH */
- struct list_head list;
- struct list_head remove_list;
+ unsigned int unlink_frame; /* When the QH was unlinked */
+ int state; /* QH_STATE_xxx; see above */
} __attribute__((aligned(16)));
/*
* We need a special accessor for the element pointer because it is
* subject to asynchronous updates by the controller.
*/
-static __le32 inline qh_element(struct uhci_qh *qh) {
+static inline __le32 qh_element(struct uhci_qh *qh) {
__le32 element = qh->element;
barrier();
@@ -149,11 +168,13 @@
#define TD_CTRL_ACTLEN_MASK 0x7FF /* actual length, encoded as n - 1 */
#define TD_CTRL_ANY_ERROR (TD_CTRL_STALLED | TD_CTRL_DBUFERR | \
- TD_CTRL_BABBLE | TD_CTRL_CRCTIME | TD_CTRL_BITSTUFF)
+ TD_CTRL_BABBLE | TD_CTRL_CRCTIME | \
+ TD_CTRL_BITSTUFF)
#define uhci_maxerr(err) ((err) << TD_CTRL_C_ERR_SHIFT)
#define uhci_status_bits(ctrl_sts) ((ctrl_sts) & 0xF60000)
-#define uhci_actual_length(ctrl_sts) (((ctrl_sts) + 1) & TD_CTRL_ACTLEN_MASK) /* 1-based */
+#define uhci_actual_length(ctrl_sts) (((ctrl_sts) + 1) & \
+ TD_CTRL_ACTLEN_MASK) /* 1-based */
/*
* for TD <info>: (a.k.a. Token)
@@ -163,7 +184,7 @@
#define TD_TOKEN_TOGGLE_SHIFT 19
#define TD_TOKEN_TOGGLE (1 << 19)
#define TD_TOKEN_EXPLEN_SHIFT 21
-#define TD_TOKEN_EXPLEN_MASK 0x7FF /* expected length, encoded as n - 1 */
+#define TD_TOKEN_EXPLEN_MASK 0x7FF /* expected length, encoded as n-1 */
#define TD_TOKEN_PID_MASK 0xFF
#define uhci_explen(len) ((((len) - 1) & TD_TOKEN_EXPLEN_MASK) << \
@@ -187,7 +208,7 @@
* sw space after the TD entry.
*
* td->link points to either another TD (not necessarily for the same urb or
- * even the same endpoint), or nothing (PTR_TERM), or a QH (for queued urbs).
+ * even the same endpoint), or nothing (PTR_TERM), or a QH.
*/
struct uhci_td {
/* Hardware fields */
@@ -210,7 +231,7 @@
* We need a special accessor for the control/status word because it is
* subject to asynchronous updates by the controller.
*/
-static u32 inline td_status(struct uhci_td *td) {
+static inline u32 td_status(struct uhci_td *td) {
__le32 status = td->status;
barrier();
@@ -223,17 +244,14 @@
*/
/*
- * The UHCI driver places Interrupt, Control and Bulk into QHs both
- * to group together TDs for one transfer, and also to facilitate queuing
- * of URBs. To make it easy to insert entries into the schedule, we have
- * a skeleton of QHs for each predefined Interrupt latency, low-speed
- * control, full-speed control and terminating QH (see explanation for
- * the terminating QH below).
+ * The UHCI driver uses QHs with Interrupt, Control and Bulk URBs for
+ * automatic queuing. To make it easy to insert entries into the schedule,
+ * we have a skeleton of QHs for each predefined Interrupt latency,
+ * low-speed control, full-speed control, bulk, and terminating QH
+ * (see explanation for the terminating QH below).
*
* When we want to add a new QH, we add it to the end of the list for the
- * skeleton QH.
- *
- * For instance, the queue can look like this:
+ * skeleton QH. For instance, the schedule list can look like this:
*
* skel int128 QH
* dev 1 interrupt QH
@@ -256,26 +274,31 @@
* - To loop back to the full-speed control queue for full-speed bandwidth
* reclamation.
*
- * Isochronous transfers are stored before the start of the skeleton
- * schedule and don't use QHs. While the UHCI spec doesn't forbid the
- * use of QHs for Isochronous, it doesn't use them either. And the spec
- * says that queues never advance on an error completion status, which
- * makes them totally unsuitable for Isochronous transfers.
+ * There's a special skeleton QH for Isochronous QHs. It never appears
+ * on the schedule, and Isochronous TDs go on the schedule before the
+ * the skeleton QHs. The hardware accesses them directly rather than
+ * through their QH, which is used only for bookkeeping purposes.
+ * While the UHCI spec doesn't forbid the use of QHs for Isochronous,
+ * it doesn't use them either. And the spec says that queues never
+ * advance on an error completion status, which makes them totally
+ * unsuitable for Isochronous transfers.
*/
-#define UHCI_NUM_SKELQH 12
-#define skel_int128_qh skelqh[0]
-#define skel_int64_qh skelqh[1]
-#define skel_int32_qh skelqh[2]
-#define skel_int16_qh skelqh[3]
-#define skel_int8_qh skelqh[4]
-#define skel_int4_qh skelqh[5]
-#define skel_int2_qh skelqh[6]
-#define skel_int1_qh skelqh[7]
-#define skel_ls_control_qh skelqh[8]
-#define skel_fs_control_qh skelqh[9]
-#define skel_bulk_qh skelqh[10]
-#define skel_term_qh skelqh[11]
+#define UHCI_NUM_SKELQH 14
+#define skel_unlink_qh skelqh[0]
+#define skel_iso_qh skelqh[1]
+#define skel_int128_qh skelqh[2]
+#define skel_int64_qh skelqh[3]
+#define skel_int32_qh skelqh[4]
+#define skel_int16_qh skelqh[5]
+#define skel_int8_qh skelqh[6]
+#define skel_int4_qh skelqh[7]
+#define skel_int2_qh skelqh[8]
+#define skel_int1_qh skelqh[9]
+#define skel_ls_control_qh skelqh[10]
+#define skel_fs_control_qh skelqh[11]
+#define skel_bulk_qh skelqh[12]
+#define skel_term_qh skelqh[13]
/*
* Search tree for determining where <interval> fits in the skelqh[]
@@ -293,21 +316,21 @@
if (interval < 16) {
if (interval < 4) {
if (interval < 2)
- return 7; /* int1 for 0-1 ms */
- return 6; /* int2 for 2-3 ms */
+ return 9; /* int1 for 0-1 ms */
+ return 8; /* int2 for 2-3 ms */
}
if (interval < 8)
- return 5; /* int4 for 4-7 ms */
- return 4; /* int8 for 8-15 ms */
+ return 7; /* int4 for 4-7 ms */
+ return 6; /* int8 for 8-15 ms */
}
if (interval < 64) {
if (interval < 32)
- return 3; /* int16 for 16-31 ms */
- return 2; /* int32 for 32-63 ms */
+ return 5; /* int16 for 16-31 ms */
+ return 4; /* int32 for 32-63 ms */
}
if (interval < 128)
- return 1; /* int64 for 64-127 ms */
- return 0; /* int128 for 128-255 ms (Max.) */
+ return 3; /* int64 for 64-127 ms */
+ return 2; /* int128 for 128-255 ms (Max.) */
}
@@ -363,12 +386,12 @@
spinlock_t lock;
- dma_addr_t frame_dma_handle; /* Hardware frame list */
+ dma_addr_t frame_dma_handle; /* Hardware frame list */
__le32 *frame;
- void **frame_cpu; /* CPU's frame list */
+ void **frame_cpu; /* CPU's frame list */
- int fsbr; /* Full-speed bandwidth reclamation */
- unsigned long fsbrtimeout; /* FSBR delay */
+ int fsbr; /* Full-speed bandwidth reclamation */
+ unsigned long fsbrtimeout; /* FSBR delay */
enum uhci_rh_state rh_state;
unsigned long auto_stop_time; /* When to AUTO_STOP */
@@ -392,24 +415,19 @@
/* Main list of URBs currently controlled by this HC */
struct list_head urb_list;
- /* List of QHs that are done, but waiting to be unlinked (race) */
- struct list_head qh_remove_list;
- unsigned int qh_remove_age; /* Age in frames */
-
/* List of TDs that are done, but waiting to be freed (race) */
struct list_head td_remove_list;
unsigned int td_remove_age; /* Age in frames */
- /* List of asynchronously unlinked URBs */
- struct list_head urb_remove_list;
- unsigned int urb_remove_age; /* Age in frames */
-
/* List of URBs awaiting completion callback */
struct list_head complete_list;
+ struct list_head idle_qh_list; /* Where the idle QHs live */
+
int rh_numports; /* Number of root-hub ports */
wait_queue_head_t waitqh; /* endpoint_disable waiters */
+ int num_waiting; /* Number of waiters */
};
/* Convert between a usb_hcd pointer and the corresponding uhci_hcd */
@@ -430,22 +448,19 @@
*/
struct urb_priv {
struct list_head urb_list;
+ struct list_head node; /* Node in the QH's urbp list */
struct urb *urb;
struct uhci_qh *qh; /* QH for this URB */
struct list_head td_list;
- unsigned fsbr : 1; /* URB turned on FSBR */
- unsigned fsbr_timeout : 1; /* URB timed out on FSBR */
- unsigned queued : 1; /* QH was queued (not linked in) */
- unsigned short_control_packet : 1; /* If we get a short packet during */
- /* a control transfer, retrigger */
- /* the status phase */
-
unsigned long fsbrtime; /* In jiffies */
- struct list_head queue_list;
+ unsigned fsbr : 1; /* URB turned on FSBR */
+ unsigned fsbr_timeout : 1; /* URB timed out on FSBR */
+ unsigned short_transfer : 1; /* URB got a short transfer, no
+ * need to rescan */
};