[Qemu-devel] [PATCH 14/18] usb: claim port at device initialization time.

[Gerd Hoffmann <kraxel@redhat.com>]

This patch makes qemu assign a port when creating the device, not when
attaching it.  For most usb devices this isn't a noticable difference
because they are in attached state all the time.

The change affects usb-host devices which live in detached state while
the real device is unplugged from the host.  They have a fixed port
assigned all the time now instead of getting grabbing one on attach and
releasing it at detach, i.e. they stop floating around at the usb bus.

The change also allows to simplify usb-hub.  It doesn't need the
handle_attach() callback any more to configure the downstream ports.
This can be done at device initialitation time now.  The changed
initialization order (first grab upstream port, then register downstream
ports) also fixes some icky corner cases.  For example it is not possible
any more to plug the hub into one of its own downstream ports.

The usb host adapters must care too.  USBPort->dev being non-NULL
doesn't imply any more the device is in attached state.  The host
adapters must additionally check the USBPort->dev->attached flag.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb-bus.c  |  110 +++++++++++++++++++++++++++++++++------------------------
 hw/usb-ehci.c |   22 ++++++------
 hw/usb-hub.c  |   12 +------
 hw/usb-ohci.c |    4 +-
 hw/usb-uhci.c |   11 +++---
 hw/usb.c      |   35 ++++++++----------
 hw/usb.h      |    5 ++-
 trace-events  |    6 +++
 8 files changed, 110 insertions(+), 95 deletions(-)

diff --git a/hw/usb-bus.c b/hw/usb-bus.c
index c0bbc7c..93f640d 100644
--- a/hw/usb-bus.c
+++ b/hw/usb-bus.c
@@ -3,6 +3,7 @@
 #include "qdev.h"
 #include "sysemu.h"
 #include "monitor.h"
+#include "trace.h"
 
 static void usb_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent);
 
@@ -73,9 +74,13 @@ static int usb_qdev_init(DeviceState *qdev, DeviceInfo *base)
     dev->info = info;
     dev->auto_attach = 1;
     QLIST_INIT(&dev->strings);
-    rc = dev->info->init(dev);
-    if (rc == 0 && dev->auto_attach)
+    rc = usb_claim_port(dev);
+    if (rc == 0) {
+        rc = dev->info->init(dev);
+    }
+    if (rc == 0 && dev->auto_attach) {
         rc = usb_device_attach(dev);
+    }
     return rc;
 }
 
@@ -89,6 +94,9 @@ static int usb_qdev_exit(DeviceState *qdev)
     if (dev->info->handle_destroy) {
         dev->info->handle_destroy(dev);
     }
+    if (dev->port) {
+        usb_release_port(dev);
+    }
     return 0;
 }
 
@@ -205,21 +213,13 @@ void usb_unregister_port(USBBus *bus, USBPort *port)
     bus->nfree--;
 }
 
-static int do_attach(USBDevice *dev)
+int usb_claim_port(USBDevice *dev)
 {
     USBBus *bus = usb_bus_from_device(dev);
     USBPort *port;
 
-    if (dev->attached) {
-        error_report("Error: tried to attach usb device %s twice\n",
-                dev->product_desc);
-        return -1;
-    }
-    if (bus->nfree == 0) {
-        error_report("Error: tried to attach usb device %s to a bus with no free ports\n",
-                dev->product_desc);
-        return -1;
-    }
+    assert(dev->port == NULL);
+
     if (dev->port_path) {
         QTAILQ_FOREACH(port, &bus->free, next) {
             if (strcmp(port->path, dev->port_path) == 0) {
@@ -227,68 +227,86 @@ static int do_attach(USBDevice *dev)
             }
         }
         if (port == NULL) {
-            error_report("Error: usb port %s (bus %s) not found\n",
-                    dev->port_path, bus->qbus.name);
+            error_report("Error: usb port %s (bus %s) not found (in use?)\n",
+                         dev->port_path, bus->qbus.name);
             return -1;
         }
     } else {
+        if (bus->nfree == 1 && strcmp(dev->qdev.info->name, "usb-hub") != 0) {
+            /* Create a new hub and chain it on */
+            usb_create_simple(bus, "usb-hub");
+        }
+        if (bus->nfree == 0) {
+            error_report("Error: tried to attach usb device %s to a bus "
+                         "with no free ports\n", dev->product_desc);
+            return -1;
+        }
         port = QTAILQ_FIRST(&bus->free);
     }
-    if (!(port->speedmask & dev->speedmask)) {
-        error_report("Warning: speed mismatch trying to attach usb device %s to bus %s\n",
-                dev->product_desc, bus->qbus.name);
-        return -1;
-    }
+    trace_usb_port_claim(bus->busnr, port->path);
 
-    dev->attached++;
     QTAILQ_REMOVE(&bus->free, port, next);
     bus->nfree--;
 
-    usb_attach(port, dev);
+    dev->port = port;
+    port->dev = dev;
 
     QTAILQ_INSERT_TAIL(&bus->used, port, next);
     bus->nused++;
-
     return 0;
 }
 
-int usb_device_attach(USBDevice *dev)
+void usb_release_port(USBDevice *dev)
 {
     USBBus *bus = usb_bus_from_device(dev);
+    USBPort *port = dev->port;
 
-    if (bus->nfree == 1 && dev->port_path == NULL) {
-        /* Create a new hub and chain it on
-           (unless a physical port location is specified). */
-        usb_create_simple(bus, "usb-hub");
-    }
-    return do_attach(dev);
+    assert(port != NULL);
+    trace_usb_port_release(bus->busnr, port->path);
+
+    QTAILQ_REMOVE(&bus->used, port, next);
+    bus->nused--;
+
+    dev->port = NULL;
+    port->dev = NULL;
+
+    QTAILQ_INSERT_TAIL(&bus->free, port, next);
+    bus->nfree++;
 }
 
-int usb_device_detach(USBDevice *dev)
+int usb_device_attach(USBDevice *dev)
 {
     USBBus *bus = usb_bus_from_device(dev);
-    USBPort *port;
+    USBPort *port = dev->port;
 
-    if (!dev->attached) {
-        error_report("Error: tried to detach unattached usb device %s\n",
-                dev->product_desc);
+    assert(port != NULL);
+    assert(!dev->attached);
+    trace_usb_port_attach(bus->busnr, port->path);
+
+    if (!(port->speedmask & dev->speedmask)) {
+        error_report("Warning: speed mismatch trying to attach "
+                     "usb device %s to bus %s\n",
+                     dev->product_desc, bus->qbus.name);
         return -1;
     }
-    dev->attached--;
 
-    QTAILQ_FOREACH(port, &bus->used, next) {
-        if (port->dev == dev)
-            break;
-    }
-    assert(port != NULL);
+    dev->attached++;
+    usb_attach(port);
 
-    QTAILQ_REMOVE(&bus->used, port, next);
-    bus->nused--;
+    return 0;
+}
+
+int usb_device_detach(USBDevice *dev)
+{
+    USBBus *bus = usb_bus_from_device(dev);
+    USBPort *port = dev->port;
 
-    usb_attach(port, NULL);
+    assert(port != NULL);
+    assert(dev->attached);
+    trace_usb_port_detach(bus->busnr, port->path);
 
-    QTAILQ_INSERT_TAIL(&bus->free, port, next);
-    bus->nfree++;
+    usb_detach(port);
+    dev->attached--;
     return 0;
 }
 
diff --git a/hw/usb-ehci.c b/hw/usb-ehci.c
index d8ef0cb..e9e0789 100644
--- a/hw/usb-ehci.c
+++ b/hw/usb-ehci.c
@@ -857,8 +857,8 @@ static void ehci_reset(void *opaque)
      */
     for(i = 0; i < NB_PORTS; i++) {
         devs[i] = s->ports[i].dev;
-        if (devs[i]) {
-            usb_attach(&s->ports[i], NULL);
+        if (devs[i] && devs[i]->attached) {
+            usb_detach(&s->ports[i]);
         }
     }
 
@@ -878,8 +878,8 @@ static void ehci_reset(void *opaque)
         } else {
             s->portsc[i] = PORTSC_PPOWER;
         }
-        if (devs[i]) {
-            usb_attach(&s->ports[i], devs[i]);
+        if (devs[i] && devs[i]->attached) {
+            usb_attach(&s->ports[i]);
         }
     }
     ehci_queues_rip_all(s);
@@ -945,15 +945,15 @@ static void handle_port_owner_write(EHCIState *s, int port, uint32_t owner)
         return;
     }
 
-    if (dev) {
-        usb_attach(&s->ports[port], NULL);
+    if (dev && dev->attached) {
+        usb_detach(&s->ports[port]);
     }
 
     *portsc &= ~PORTSC_POWNER;
     *portsc |= owner;
 
-    if (dev) {
-        usb_attach(&s->ports[port], dev);
+    if (dev && dev->attached) {
+        usb_attach(&s->ports[port]);
     }
 }
 
@@ -977,8 +977,8 @@ static void handle_port_status_write(EHCIState *s, int port, uint32_t val)
 
     if (!(val & PORTSC_PRESET) &&(*portsc & PORTSC_PRESET)) {
         trace_usb_ehci_port_reset(port, 0);
-        if (dev) {
-            usb_attach(&s->ports[port], dev);
+        if (dev && dev->attached) {
+            usb_attach(&s->ports[port]);
             usb_send_msg(dev, USB_MSG_RESET);
             *portsc &= ~PORTSC_CSC;
         }
@@ -987,7 +987,7 @@ static void handle_port_status_write(EHCIState *s, int port, uint32_t val)
          *  Table 2.16 Set the enable bit(and enable bit change) to indicate
          *  to SW that this port has a high speed device attached
          */
-        if (dev && (dev->speedmask & USB_SPEED_MASK_HIGH)) {
+        if (dev && dev->attached && (dev->speedmask & USB_SPEED_MASK_HIGH)) {
             val |= PORTSC_PED;
         }
     }
diff --git a/hw/usb-hub.c b/hw/usb-hub.c
index c49c547..286e3ad 100644
--- a/hw/usb-hub.c
+++ b/hw/usb-hub.c
@@ -213,16 +213,6 @@ static void usb_hub_complete(USBPort *port, USBPacket *packet)
     usb_packet_complete(&s->dev, packet);
 }
 
-static void usb_hub_handle_attach(USBDevice *dev)
-{
-    USBHubState *s = DO_UPCAST(USBHubState, dev, dev);
-    int i;
-
-    for (i = 0; i < NUM_PORTS; i++) {
-        usb_port_location(&s->ports[i].port, dev->port, i+1);
-    }
-}
-
 static void usb_hub_handle_reset(USBDevice *dev)
 {
     /* XXX: do it */
@@ -499,6 +489,7 @@ static int usb_hub_initfn(USBDevice *dev)
         usb_register_port(usb_bus_from_device(dev),
                           &port->port, s, i, &usb_hub_port_ops,
                           USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL);
+        usb_port_location(&port->port, dev->port, i+1);
         port->wPortStatus = PORT_STAT_POWER;
         port->wPortChange = 0;
     }
@@ -537,7 +528,6 @@ static struct USBDeviceInfo hub_info = {
     .usb_desc       = &desc_hub,
     .init           = usb_hub_initfn,
     .handle_packet  = usb_hub_handle_packet,
-    .handle_attach  = usb_hub_handle_attach,
     .handle_reset   = usb_hub_handle_reset,
     .handle_control = usb_hub_handle_control,
     .handle_data    = usb_hub_handle_data,
diff --git a/hw/usb-ohci.c b/hw/usb-ohci.c
index d30db3f..503ca2d 100644
--- a/hw/usb-ohci.c
+++ b/hw/usb-ohci.c
@@ -448,8 +448,8 @@ static void ohci_reset(void *opaque)
       {
         port = &ohci->rhport[i];
         port->ctrl = 0;
-        if (port->port.dev) {
-            usb_attach(&port->port, port->port.dev);
+        if (port->port.dev && port->port.dev->attached) {
+            usb_attach(&port->port);
         }
       }
     if (ohci->async_td) {
diff --git a/hw/usb-uhci.c b/hw/usb-uhci.c
index 6ca7ca8..64f7b36 100644
--- a/hw/usb-uhci.c
+++ b/hw/usb-uhci.c
@@ -340,8 +340,8 @@ static void uhci_reset(void *opaque)
     for(i = 0; i < NB_PORTS; i++) {
         port = &s->ports[i];
         port->ctrl = 0x0080;
-        if (port->port.dev) {
-            usb_attach(&port->port, port->port.dev);
+        if (port->port.dev && port->port.dev->attached) {
+            usb_attach(&port->port);
         }
     }
 
@@ -446,7 +446,7 @@ static void uhci_ioport_writew(void *opaque, uint32_t addr, uint32_t val)
             for(i = 0; i < NB_PORTS; i++) {
                 port = &s->ports[i];
                 dev = port->port.dev;
-                if (dev) {
+                if (dev && dev->attached) {
                     usb_send_msg(dev, USB_MSG_RESET);
                 }
             }
@@ -486,7 +486,7 @@ static void uhci_ioport_writew(void *opaque, uint32_t addr, uint32_t val)
                 return;
             port = &s->ports[n];
             dev = port->port.dev;
-            if (dev) {
+            if (dev && dev->attached) {
                 /* port reset */
                 if ( (val & UHCI_PORT_RESET) &&
                      !(port->ctrl & UHCI_PORT_RESET) ) {
@@ -660,8 +660,9 @@ static int uhci_broadcast_packet(UHCIState *s, USBPacket *p)
         UHCIPort *port = &s->ports[i];
         USBDevice *dev = port->port.dev;
 
-        if (dev && (port->ctrl & UHCI_PORT_EN))
+        if (dev && dev->attached && (port->ctrl & UHCI_PORT_EN)) {
             ret = usb_handle_packet(dev, p);
+        }
     }
 
     DPRINTF("uhci: packet exit. ret %d len %zd\n", ret, p->iov.size);
diff --git a/hw/usb.c b/hw/usb.c
index a091e4e..fa90204 100644
--- a/hw/usb.c
+++ b/hw/usb.c
@@ -27,26 +27,23 @@
 #include "usb.h"
 #include "iov.h"
 
-void usb_attach(USBPort *port, USBDevice *dev)
+void usb_attach(USBPort *port)
 {
-    if (dev != NULL) {
-        /* attach */
-        if (port->dev) {
-            usb_attach(port, NULL);
-        }
-        dev->port = port;
-        port->dev = dev;
-        port->ops->attach(port);
-        usb_send_msg(dev, USB_MSG_ATTACH);
-    } else {
-        /* detach */
-        dev = port->dev;
-        assert(dev);
-        port->ops->detach(port);
-        usb_send_msg(dev, USB_MSG_DETACH);
-        dev->port = NULL;
-        port->dev = NULL;
-    }
+    USBDevice *dev = port->dev;
+
+    assert(dev != NULL);
+    assert(dev->attached);
+    port->ops->attach(port);
+    usb_send_msg(dev, USB_MSG_ATTACH);
+}
+
+void usb_detach(USBPort *port)
+{
+    USBDevice *dev = port->dev;
+
+    assert(dev != NULL);
+    port->ops->detach(port);
+    usb_send_msg(dev, USB_MSG_DETACH);
 }
 
 void usb_wakeup(USBDevice *dev)
diff --git a/hw/usb.h b/hw/usb.h
index d784448..73479d6 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -304,7 +304,8 @@ int usb_handle_packet(USBDevice *dev, USBPacket *p);
 void usb_packet_complete(USBDevice *dev, USBPacket *p);
 void usb_cancel_packet(USBPacket * p);
 
-void usb_attach(USBPort *port, USBDevice *dev);
+void usb_attach(USBPort *port);
+void usb_detach(USBPort *port);
 void usb_wakeup(USBDevice *dev);
 int usb_generic_handle_packet(USBDevice *s, USBPacket *p);
 void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p);
@@ -378,6 +379,8 @@ int usb_register_companion(const char *masterbus, USBPort *ports[],
                            void *opaque, USBPortOps *ops, int speedmask);
 void usb_port_location(USBPort *downstream, USBPort *upstream, int portnr);
 void usb_unregister_port(USBBus *bus, USBPort *port);
+int usb_claim_port(USBDevice *dev);
+void usb_release_port(USBDevice *dev);
 int usb_device_attach(USBDevice *dev);
 int usb_device_detach(USBDevice *dev);
 int usb_device_delete_addr(int busnr, int addr);
diff --git a/trace-events b/trace-events
index d4628a9..8005974 100644
--- a/trace-events
+++ b/trace-events
@@ -212,6 +212,12 @@ disable sun4m_iommu_page_get_flags(uint64_t pa, uint64_t iopte, uint32_t ret) "g
 disable sun4m_iommu_translate_pa(uint64_t addr, uint64_t pa, uint32_t iopte) "xlate dva %"PRIx64" => pa %"PRIx64" iopte = %x"
 disable sun4m_iommu_bad_addr(uint64_t addr) "bad addr %"PRIx64""
 
+# hw/usb-bus.c
+usb_port_claim(int bus, const char *port) "bus %d, port %s"
+usb_port_attach(int bus, const char *port) "bus %d, port %s"
+usb_port_detach(int bus, const char *port) "bus %d, port %s"
+usb_port_release(int bus, const char *port) "bus %d, port %s"
+
 # hw/usb-ehci.c
 disable usb_ehci_reset(void) "=== RESET ==="
 disable usb_ehci_mmio_readl(uint32_t addr, const char *str, uint32_t val) "rd mmio %04x [%s] = %x"
-- 
1.7.1