usb-ehci: Fix handling of PED and PEDC port status bits

The PED bit should only be set for highspeed devices and the PEDC bit
should not be set on "normal" PED bit changes, only on io errors.
Signed-off-by: NHans de Goede <hdegoede@redhat.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>

hw/usb-ehci.c

@@ -106,7 +106,7 @@
  * Bits that are reserved or are read-only are masked out of values
  * written to us by software
  */
-#define PORTSC_RO_MASK       0x007021c4
+#define PORTSC_RO_MASK       0x007021c0
 #define PORTSC_RWC_MASK      0x0000002a
 #define PORTSC_WKOC_E        (1 << 22)    // Wake on Over Current Enable
 #define PORTSC_WKDS_E        (1 << 21)    // Wake on Disconnect Enable
@@ -752,7 +752,7 @@ static void ehci_detach(USBPort *port)
 
     ehci_queues_rip_device(s, port->dev);
 
-    *portsc &= ~PORTSC_CONNECT;
+    *portsc &= ~(PORTSC_CONNECT|PORTSC_PED);
     *portsc |= PORTSC_CSC;
 
     /*
@@ -847,16 +847,14 @@ static void ehci_mem_writew(void *ptr, target_phys_addr_t addr, uint32_t val)
 static void handle_port_status_write(EHCIState *s, int port, uint32_t val)
 {
     uint32_t *portsc = &s->portsc[port];
-    int rwc;
     USBDevice *dev = s->ports[port].dev;
 
-    rwc = val & PORTSC_RWC_MASK;
+    /* Clear rwc bits */
+    *portsc &= ~(val & PORTSC_RWC_MASK);
+    /* The guest may clear, but not set the PED bit */
+    *portsc &= val | ~PORTSC_PED;
     val &= PORTSC_RO_MASK;
 
-    // handle_read_write_clear(&val, portsc, PORTSC_PEDC | PORTSC_CSC);
-
-    *portsc &= ~rwc;
-
     if ((val & PORTSC_PRESET) && !(*portsc & PORTSC_PRESET)) {
         trace_usb_ehci_port_reset(port, 1);
     }
@@ -869,13 +867,13 @@ static void handle_port_status_write(EHCIState *s, int port, uint32_t val)
             *portsc &= ~PORTSC_CSC;
         }
 
-        /*  Table 2.16 Set the enable bit(and enable bit change) to indicate
+        /*
+         *  Table 2.16 Set the enable bit(and enable bit change) to indicate
          *  to SW that this port has a high speed device attached
-         *
-         *  TODO - when to disable?
          */
-        val |= PORTSC_PED;
-        val |= PORTSC_PEDC;
+        if (dev && (dev->speedmask & USB_SPEED_MASK_HIGH)) {
+            val |= PORTSC_PED;
+        }
     }
 
     *portsc &= ~PORTSC_RO_MASK;