xhci: dbc: refactor xhci_dbc_init()

Refactor xhci_dbc_init(), splitting it into logical
parts closer to the Linux device model.

- Create the fake dbc device, depends on xhci strucure
- Allocate a dbc structure, xhci agnostic
- Call xhci_dbc_tty_probe(), similar to actual probe.

Adjustments to xhci_dbc_exit and xhci_dbc_remove are also needed
as a result to the xhci_dbc_init() changes

Mostly non-functional changes, except for creating the dbc sysfs
entry earlier, together with the dbc structure.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220216095153.1303105-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
index ccb0156fcebebf2afd72ad4945f5444ad03eda66..6a437862b4980a758474808de440f3715458f7c3 100644 (file)
--- a/drivers/usb/host/xhci-dbgcap.c
+++ b/drivers/usb/host/xhci-dbgcap.c
@@ -924,49 +924,6 @@ static void xhci_do_dbc_exit(struct xhci_hcd *xhci)
        spin_unlock_irqrestore(&xhci->lock, flags);
 }
 
-static int xhci_do_dbc_init(struct xhci_hcd *xhci)
-{
-       u32                     reg;
-       struct xhci_dbc         *dbc;
-       unsigned long           flags;
-       void __iomem            *base;
-       int                     dbc_cap_offs;
-
-       base = &xhci->cap_regs->hc_capbase;
-       dbc_cap_offs = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
-       if (!dbc_cap_offs)
-               return -ENODEV;
-
-       dbc = kzalloc(sizeof(*dbc), GFP_KERNEL);
-       if (!dbc)
-               return -ENOMEM;
-
-       dbc->regs = base + dbc_cap_offs;
-
-       /* We will avoid using DbC in xhci driver if it's in use. */
-       reg = readl(&dbc->regs->control);
-       if (reg & DBC_CTRL_DBC_ENABLE) {
-               kfree(dbc);
-               return -EBUSY;
-       }
-
-       spin_lock_irqsave(&xhci->lock, flags);
-       if (xhci->dbc) {
-               spin_unlock_irqrestore(&xhci->lock, flags);
-               kfree(dbc);
-               return -EBUSY;
-       }
-       xhci->dbc = dbc;
-       spin_unlock_irqrestore(&xhci->lock, flags);
-
-       dbc->xhci = xhci;
-       dbc->dev = xhci_to_hcd(xhci)->self.sysdev;
-       INIT_DELAYED_WORK(&dbc->event_work, xhci_dbc_handle_events);
-       spin_lock_init(&dbc->lock);
-
-       return 0;
-}
-
 static ssize_t dbc_show(struct device *dev,
                        struct device_attribute *attr,
                        char *buf)
@@ -1026,44 +983,95 @@ static ssize_t dbc_store(struct device *dev,
 
 static DEVICE_ATTR_RW(dbc);
 
-int xhci_dbc_init(struct xhci_hcd *xhci)
+struct xhci_dbc *
+xhci_alloc_dbc(struct device *dev, void __iomem *base)
 {
+       struct xhci_dbc         *dbc;
        int                     ret;
-       struct device           *dev = xhci_to_hcd(xhci)->self.controller;
 
-       ret = xhci_do_dbc_init(xhci);
+       dbc = kzalloc(sizeof(*dbc), GFP_KERNEL);
+       if (!dbc)
+               return NULL;
+
+       dbc->regs = base;
+       dbc->dev = dev;
+
+       if (readl(&dbc->regs->control) & DBC_CTRL_DBC_ENABLE)
+               return NULL;
+
+       INIT_DELAYED_WORK(&dbc->event_work, xhci_dbc_handle_events);
+       spin_lock_init(&dbc->lock);
+
+       ret = device_create_file(dev, &dev_attr_dbc);
        if (ret)
-               goto init_err3;
+               goto err;
+
+       return dbc;
+err:
+       kfree(dbc);
+       return NULL;
+}
+
+/* undo what xhci_alloc_dbc() did */
+void xhci_dbc_remove(struct xhci_dbc *dbc)
+{
+       if (!dbc)
+               return;
+       /* stop hw, stop wq and call dbc->ops->stop() */
+       xhci_dbc_stop(dbc);
+
+       /* remove sysfs files */
+       device_remove_file(dbc->dev, &dev_attr_dbc);
+
+       kfree(dbc);
+}
+
+int xhci_dbc_init(struct xhci_hcd *xhci)
+{
+       struct device           *dev;
+       void __iomem            *base;
+       int                     ret;
+       int                     dbc_cap_offs;
+
+       /* create all parameters needed resembling a dbc device */
+       dev = xhci_to_hcd(xhci)->self.controller;
+       base = &xhci->cap_regs->hc_capbase;
+
+       dbc_cap_offs = xhci_find_next_ext_cap(base, 0, XHCI_EXT_CAPS_DEBUG);
+       if (!dbc_cap_offs)
+               return -ENODEV;
+
+       /* already allocated and in use */
+       if (xhci->dbc)
+               return -EBUSY;
+
+       xhci->dbc = xhci_alloc_dbc(dev, base);
+       if (!xhci->dbc)
+               return -ENOMEM;
 
        ret = xhci_dbc_tty_probe(xhci);
        if (ret)
                goto init_err2;
 
-       ret = device_create_file(dev, &dev_attr_dbc);
-       if (ret)
-               goto init_err1;
-
        return 0;
 
-init_err1:
-       xhci_dbc_tty_remove(xhci->dbc);
 init_err2:
        xhci_do_dbc_exit(xhci);
-init_err3:
        return ret;
 }
 
 void xhci_dbc_exit(struct xhci_hcd *xhci)
 {
-       struct device           *dev = xhci_to_hcd(xhci)->self.controller;
+       unsigned long           flags;
 
        if (!xhci->dbc)
                return;
 
-       device_remove_file(dev, &dev_attr_dbc);
        xhci_dbc_tty_remove(xhci->dbc);
-       xhci_dbc_stop(xhci->dbc);
-       xhci_do_dbc_exit(xhci);
+       xhci_dbc_remove(xhci->dbc);
+       spin_lock_irqsave(&xhci->lock, flags);
+       xhci->dbc = NULL;
+       spin_unlock_irqrestore(&xhci->lock, flags);
 }
 
 #ifdef CONFIG_PM