Disabling device intx assertions in order to enable MSI-x

drivers/driver.cc

@@ -54,6 +54,17 @@ void Driver::setStatus(u16 s) {
     write_pci_config_word(_bus,_slot,_func,PCI_STATUS_OFFSET,s);
 }
 
+u16 Driver::get_command(void)
+{
+    return (pci_readw(PCI_COMMAND_OFFSET));
+}
+
+void Driver::set_command(u16 c)
+{
+    pci_writew(PCI_COMMAND_OFFSET, c);
+}
+
+
 u8
 Driver::getRevision() {
     if (!_present) throw new InitException();
@@ -117,10 +128,16 @@ Driver::Init(Device* dev) {
 
     parse_pci_config();
 
-    debug(fmt("Driver:Init %x:%x") % _vid % _id);
-
     setBusMaster(true);
 
+    // Enable MSI-x
+    if (_have_msix) {
+        if (is_intx_enabled()) {
+            disable_intx();
+        }
+    }
+
+    debug(fmt("Driver initialized %x:%x") % _vid % _id);
     return true;
 }
 
@@ -210,6 +227,26 @@ bool Driver::parse_pci_msix(u8 off)
     return true;
 }
 
+bool Driver::is_intx_enabled(void)
+{
+    u16 command = get_command();
+    return ( (command & PCI_COMMAND_INTX_DISABLE) == 0 );
+}
+
+void Driver::enable_intx(void)
+{
+    u16 command = get_command();
+    command &= ~PCI_COMMAND_INTX_DISABLE;
+    set_command(command);
+}
+
+void Driver::disable_intx(void)
+{
+    u16 command = get_command();
+    command |= PCI_COMMAND_INTX_DISABLE;
+    set_command(command);
+}
+
 u8 Driver::pci_readb(u8 offset)
 {
     return read_pci_config_byte(_bus, _slot, _func, offset);

drivers/driver.hh

@@ -50,6 +50,8 @@ public:
 
     u16 getStatus();
     void setStatus(u16 s);
+    u16 get_command(void);
+    void set_command(u16 c);
     bool getBusMaster();
     void setBusMaster(bool m);
     virtual void dumpConfig() const;
@@ -88,6 +90,13 @@ protected:
     bool allocateBARs();
     virtual bool earlyInitChecks();
 
+    // Enable/Disable intx assertions
+    bool is_intx_enabled(void);
+    // Enable intx assertion
+    // intx assertions should be disabled in order to use MSI-x
+    void enable_intx(void);
+    void disable_intx(void);
+
     // Parsing of extra capabilities
     virtual bool parse_pci_capabilities(void);
     virtual bool parse_pci_msix(u8 off);

drivers/pci.hh

@@ -63,6 +63,10 @@ using processor::outl;
 	    PCI_CAPABILITIES_PTR = 0x34,
 	};
 
+	enum pci_command_bits {
+	    PCI_COMMAND_INTX_DISABLE = (1 << 10),
+	};
+
 	//  Capability Register Offsets
 	enum pci_capabilities_offsets {
 	    PCI_CAP_OFF_ID      = 0x0,