Introduce the notion of a PCI device that may be associated with more than
one USB host controller driver (struct usb_hcd). This patch is the start
of the work to separate the xHCI host controller into two roothubs: a USB
3.0 roothub with SuperSpeed-only ports, and a USB 2.0 roothub with
HS/FS/LS ports.
One usb_hcd structure is designated to be the "primary HCD", and a pointer
is added to the usb_hcd structure to keep track of that. A new function
call, usb_hcd_is_primary_hcd() is added to check whether the USB hcd is
marked as the primary HCD (or if it is not part of a roothub pair). To
allow the USB core and xHCI driver to access either roothub in a pair, a
"shared_hcd" pointer is added to the usb_hcd structure.
Add a new function, usb_create_shared_hcd(), that does roothub allocation
for paired roothubs. It will act just like usb_create_hcd() did if the
primary_hcd pointer argument is NULL. If it is passed a non-NULL
primary_hcd pointer, it sets usb_hcd->shared_hcd and usb_hcd->primary_hcd
fields. It will also skip the bandwidth_mutex allocation, and set the
secondary hcd's bandwidth_mutex pointer to the primary HCD's mutex.
IRQs are only allocated once for the primary roothub.
Introduce a new usb_hcd driver flag that indicates the host controller
driver wants to create two roothubs. If the HCD_SHARED flag is set, then
the USB core PCI probe methods will allocate a second roothub, and make
sure that second roothub gets freed during rmmod and in initialization
error paths.
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
---
drivers/usb/core/hcd.c | 91 +++++++++++++++++++++++++++++++++++++---------
include/linux/usb/hcd.h | 7 ++++
2 files changed, 80 insertions(+), 18 deletions(-)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 0c4f0aa..f807890 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2132,10 +2132,12 @@ EXPORT_SYMBOL_GPL (usb_hc_died);
/*-------------------------------------------------------------------------*/
/**
- * usb_create_hcd - create and initialize an HCD structure
+ * usb_create_shared_hcd - create and initialize an HCD structure
* @driver: HC driver that will use this hcd
* @dev: device for this HC, stored in hcd->self.controller
* @bus_name: value to store in hcd->self.bus_name
+ * @primary_hcd: a pointer to the usb_hcd structure that is sharing the
+ * PCI device. Only allocate certain resources for the primary HCD
* Context: !in_interrupt()
*
* Allocate a struct usb_hcd, with extra space at the end for the
@@ -2144,8 +2146,9 @@ EXPORT_SYMBOL_GPL (usb_hc_died);
*
* If memory is unavailable, returns NULL.
*/
-struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
- struct device *dev, const char *bus_name)
+struct usb_hcd *usb_create_shared_hcd(const struct hc_driver *driver,
+ struct device *dev, const char *bus_name,
+ struct usb_hcd *primary_hcd)
{
struct usb_hcd *hcd;
@@ -2154,16 +2157,24 @@ struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
dev_dbg (dev, "hcd alloc failed\n");
return NULL;
}
- hcd->bandwidth_mutex = kmalloc(sizeof(*hcd->bandwidth_mutex),
- GFP_KERNEL);
- if (!hcd->bandwidth_mutex) {
- kfree(hcd);
- dev_dbg(dev, "hcd bandwidth mutex alloc failed\n");
- return NULL;
+ if (primary_hcd == NULL) {
+ hcd->bandwidth_mutex = kmalloc(sizeof(*hcd->bandwidth_mutex),
+ GFP_KERNEL);
+ if (!hcd->bandwidth_mutex) {
+ kfree(hcd);
+ dev_dbg(dev, "hcd bandwidth mutex alloc failed\n");
+ return NULL;
+ }
+ mutex_init(hcd->bandwidth_mutex);
+ dev_set_drvdata(dev, hcd);
+ } else {
+ hcd->bandwidth_mutex = primary_hcd->bandwidth_mutex;
+ hcd->primary_hcd = primary_hcd;
+ primary_hcd->primary_hcd = primary_hcd;
+ hcd->shared_hcd = primary_hcd;
+ primary_hcd->shared_hcd = hcd;
}
- mutex_init(hcd->bandwidth_mutex);
- dev_set_drvdata(dev, hcd);
kref_init(&hcd->kref);
usb_bus_init(&hcd->self);
@@ -2184,13 +2195,45 @@ struct usb_hcd *usb_create_hcd (const struct hc_driver *driver,
"USB Host Controller";
return hcd;
}
+EXPORT_SYMBOL_GPL(usb_create_shared_hcd);
+
+/**
+ * usb_create_hcd - create and initialize an HCD structure
+ * @driver: HC driver that will use this hcd
+ * @dev: device for this HC, stored in hcd->self.controller
+ * @bus_name: value to store in hcd->self.bus_name
+ * Context: !in_interrupt()
+ *
+ * Allocate a struct usb_hcd, with extra space at the end for the
+ * HC driver's private data. Initialize the generic members of the
+ * hcd structure.
+ *
+ * If memory is unavailable, returns NULL.
+ */
+struct usb_hcd *usb_create_hcd(const struct hc_driver *driver,
+ struct device *dev, const char *bus_name)
+{
+ return usb_create_shared_hcd(driver, dev, bus_name, NULL);
+}
EXPORT_SYMBOL_GPL(usb_create_hcd);
+/*
+ * Roothubs that share one PCI device must also share the bandwidth mutex.
+ * Don't deallocate the bandwidth_mutex until the last shared usb_hcd is
+ * deallocated.
+ *
+ * The first shared roothub that is released will set shared_hcd to NULL. The
+ * second shared roothub that is released (or a USB host controller driver that
+ * doesn't set up shared roothubs) will deallocate the bandwidth mutex.
+ */
static void hcd_release (struct kref *kref)
{
struct usb_hcd *hcd = container_of (kref, struct usb_hcd, kref);
- kfree(hcd->bandwidth_mutex);
+ if (hcd->shared_hcd)
+ hcd->shared_hcd->shared_hcd = NULL;
+ else
+ kfree(hcd->bandwidth_mutex);
kfree(hcd);
}
@@ -2209,6 +2252,14 @@ void usb_put_hcd (struct usb_hcd *hcd)
}
EXPORT_SYMBOL_GPL(usb_put_hcd);
+inline int usb_hcd_is_primary_hcd(struct usb_hcd *hcd)
+{
+ if (!hcd->primary_hcd)
+ return 1;
+ return hcd == hcd->primary_hcd;
+}
+EXPORT_SYMBOL_GPL(usb_hcd_is_primary_hcd);
+
static int usb_hcd_request_irqs(struct usb_hcd *hcd,
unsigned int irqnum, unsigned long irqflags)
{
@@ -2324,9 +2375,11 @@ int usb_add_hcd(struct usb_hcd *hcd,
dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
/* enable irqs just before we start the controller */
- retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
- if (retval)
- goto err_request_irq;
+ if (usb_hcd_is_primary_hcd(hcd)) {
+ retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
+ if (retval)
+ goto err_request_irq;
+ }
retval = hcd->driver->start(hcd);
if (retval < 0) {
@@ -2371,7 +2424,7 @@ err_register_root_hub:
clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
del_timer_sync(&hcd->rh_timer);
err_hcd_driver_start:
- if (hcd->irq >= 0)
+ if (usb_hcd_is_primary_hcd(hcd) && hcd->irq >= 0)
free_irq(irqnum, hcd);
err_request_irq:
err_hcd_driver_setup:
@@ -2434,8 +2487,10 @@ void usb_remove_hcd(struct usb_hcd *hcd)
clear_bit(HCD_FLAG_POLL_RH, &hcd->flags);
del_timer_sync(&hcd->rh_timer);
- if (hcd->irq >= 0)
- free_irq(hcd->irq, hcd);
+ if (usb_hcd_is_primary_hcd(hcd)) {
+ if (hcd->irq >= 0)
+ free_irq(hcd->irq, hcd);
+ }
usb_put_dev(hcd->self.root_hub);
usb_deregister_bus(&hcd->self);
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 86e3d62..9931855 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -143,6 +143,8 @@ struct usb_hcd {
* to the device, or resetting the bandwidth after a failed attempt.
*/
struct mutex *bandwidth_mutex;
+ struct usb_hcd *shared_hcd;
+ struct usb_hcd *primary_hcd;
#define HCD_BUFFER_POOLS 4
@@ -205,6 +207,7 @@ struct hc_driver {
int flags;
#define HCD_MEMORY 0x0001 /* HC regs use memory (else I/O) */
#define HCD_LOCAL_MEM 0x0002 /* HC needs local memory */
+#define HCD_SHARED 0x0004 /* Two (or more) usb_hcds share HW */
#define HCD_USB11 0x0010 /* USB 1.1 */
#define HCD_USB2 0x0020 /* USB 2.0 */
#define HCD_USB3 0x0040 /* USB 3.0 */
@@ -351,8 +354,12 @@ extern int usb_hcd_get_frame_number(struct usb_device *udev);
extern struct usb_hcd *usb_create_hcd(const struct hc_driver *driver,
struct device *dev, const char *bus_name);
+extern struct usb_hcd *usb_create_shared_hcd(const struct hc_driver *driver,
+ struct device *dev, const char *bus_name,
+ struct usb_hcd *shared_hcd);
extern struct usb_hcd *usb_get_hcd(struct usb_hcd *hcd);
extern void usb_put_hcd(struct usb_hcd *hcd);
+extern inline int usb_hcd_is_primary_hcd(struct usb_hcd *hcd);
extern int usb_add_hcd(struct usb_hcd *hcd,
unsigned int irqnum, unsigned long irqflags);
extern void usb_remove_hcd(struct usb_hcd *hcd);
--
1.7.0.4
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