[RFC PATCH 12/12] usb: xhci: prepare IRQ handler for multiple interrupters

[Niklas Neronin <niklas.neronin@linux.intel.com>]

The xHCI driver currently assumes a single interrupter (index 0), and the
IRQ handler receives a pointer to the struct 'xhci', from which it directly
accesses 'xhci->interrupters[0]'.

To support multiple interrupters, the IRQ handler must be able to identify
the specific interrupter instance that triggered the interrupt. Do this by
passing a pointer to the corresponding struct 'xhci_interrupter' instead of
the global struct 'xhci'. Add a back-pointer to struct 'xhci' in struct
'xhci_interrupter' so the handler can still access ore data.

This change is necessary to prepare the driver for multiple interrupters.

Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>
---
 drivers/usb/host/xhci-mem.c  |  1 +
 drivers/usb/host/xhci-pci.c  |  2 +-
 drivers/usb/host/xhci-ring.c | 19 ++++++++++++++-----
 drivers/usb/host/xhci.h      |  3 ++-
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index a6fde127c569..30eb0a79ef20 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2331,6 +2331,7 @@ void xhci_add_interrupter(struct xhci_hcd *xhci, unsigned int intr_num)
 	u32 erst_size;
 
 	ir = xhci->interrupters[intr_num];
+	ir->xhci = xhci;
 	ir->intr_num = intr_num;
 	ir->ir_set = &xhci->run_regs->ir_set[intr_num];
 
diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index ea43b0153430..c1b8062c5467 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -175,7 +175,7 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
 	}
 
 	ret = request_irq(pci_irq_vector(pdev, 0), xhci_msi_irq, 0, "xhci_hcd",
-			  xhci_to_hcd(xhci));
+			  &xhci->interrupters[0]);
 	if (ret)
 		goto free_irq_vectors;
 
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 9315ba18310d..5e303f8f0e4f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3174,9 +3174,9 @@ void xhci_skip_sec_intr_events(struct xhci_hcd *xhci,
  * we might get bad data out of the event ring.  Section 4.10.2.7 has a list of
  * indicators of an event TRB error, but we check the status *first* to be safe.
  */
-irqreturn_t xhci_irq(struct usb_hcd *hcd)
+static irqreturn_t xhci_irq_handler(struct xhci_interrupter *ir)
 {
-	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct xhci_hcd *xhci = ir->xhci;
 	irqreturn_t ret = IRQ_HANDLED;
 	u32 status;
 
@@ -3213,16 +3213,25 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
 	writel(status, &xhci->op_regs->status);
 
 	/* This is the handler of the primary interrupter */
-	xhci_handle_events(xhci, xhci->interrupters[0], false);
+	xhci_handle_events(xhci, ir, false);
 out:
 	spin_unlock(&xhci->lock);
 
 	return ret;
 }
 
-irqreturn_t xhci_msi_irq(int irq, void *hcd)
+irqreturn_t xhci_irq(struct usb_hcd *hcd)
 {
-	return xhci_irq(hcd);
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+	return xhci_irq_handler(xhci->interrupters[0]);
+}
+
+irqreturn_t xhci_msi_irq(int irq, void *data)
+{
+	struct xhci_interrupter *ir = *(struct xhci_interrupter **)data;
+
+	return xhci_irq_handler(ir);
 }
 EXPORT_SYMBOL_GPL(xhci_msi_irq);
 
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 1e9ea6507813..1b177882851f 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1451,6 +1451,7 @@ enum interrupter_type {
 };
 
 struct xhci_interrupter {
+	struct xhci_hcd		*xhci;
 	struct xhci_ring	*event_ring;
 	struct xhci_erst	erst;
 	struct xhci_intr_reg __iomem *ir_set;
@@ -1905,7 +1906,7 @@ int xhci_suspend(struct xhci_hcd *xhci, bool do_wakeup);
 int xhci_resume(struct xhci_hcd *xhci, bool power_lost, bool is_auto_resume);
 
 irqreturn_t xhci_irq(struct usb_hcd *hcd);
-irqreturn_t xhci_msi_irq(int irq, void *hcd);
+irqreturn_t xhci_msi_irq(int irq, void *data);
 int xhci_alloc_dev(struct usb_hcd *hcd, struct usb_device *udev);
 int xhci_alloc_tt_info(struct xhci_hcd *xhci,
 		struct xhci_virt_device *virt_dev,
-- 
2.50.1