[PATCH] pSeries - read irqs dynamically

For I/O DLPAR to work properly, the kernel needs to allow for dynamic
assignment of the irq field of the pci_dev structure upon dynamic bus
addition.  This patch moves the assignment of that field from
pSeries_final_fixup() to pcibios_fixup_bus(), which enables dynamic
assignment for the children of a newly added bus.

Currently, pci_devs receive their irq numbers in one of two ways.  The
irq line is either read at boot for all pci_devs, or read by the rpaphp
module at slot enable time.  The latter is no longer sufficient for
DLPAR addition of slots that don't qualify as PCI-hotplug capable.
This solution handles the cases of boot and dynamic add.

Signed-off-by: John Rose <johnrose@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/ppc64/kernel/pSeries_pci.c

@@ -32,7 +32,7 @@
 
 #include "pci.h"
 
-static int __initdata s7a_workaround;
+static int __initdata s7a_workaround = -1;
 
 #if 0
 void pcibios_name_device(struct pci_dev *dev)
@@ -65,6 +65,7 @@ static void __init check_s7a(void)
 	struct device_node *root;
 	char *model;
 
+	s7a_workaround = 0;
 	root = of_find_node_by_path("/");
 	if (root) {
 		model = get_property(root, "model", NULL);
@@ -74,6 +75,24 @@ static void __init check_s7a(void)
 	}
 }
 
+void __devinit pSeries_irq_bus_setup(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	if (s7a_workaround < 0)
+		check_s7a();
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		pci_read_irq_line(dev);
+		if (s7a_workaround) {
+			if (dev->irq > 16) {
+				dev->irq -= 3;
+				pci_write_config_byte(dev, PCI_INTERRUPT_LINE,
+					dev->irq);
+			}
+		}
+	}
+}
+
 static void __init pSeries_request_regions(void)
 {
 	if (!isa_io_base)
@@ -89,20 +108,6 @@ static void __init pSeries_request_regions(void)
 
 void __init pSeries_final_fixup(void)
 {
-	struct pci_dev *dev = NULL;
-
-	check_s7a();
-
-	for_each_pci_dev(dev) {
-		pci_read_irq_line(dev);
-		if (s7a_workaround) {
-			if (dev->irq > 16) {
-				dev->irq -= 3;
-				pci_write_config_byte(dev, PCI_INTERRUPT_LINE, dev->irq);
-			}
-		}
-	}
-
 	phbs_remap_io();
 	pSeries_request_regions();
 

arch/ppc64/kernel/pSeries_setup.c

@@ -71,8 +71,6 @@
 #define DBG(fmt...)
 #endif
 
-extern void pSeries_final_fixup(void);
-
 extern void find_udbg_vterm(void);
 extern void system_reset_fwnmi(void);	/* from head.S */
 extern void machine_check_fwnmi(void);	/* from head.S */
@@ -425,6 +423,7 @@ struct machdep_calls __initdata pSeries_md = {
 	.get_cpuinfo		= pSeries_get_cpuinfo,
 	.log_error		= pSeries_log_error,
 	.pcibios_fixup		= pSeries_final_fixup,
+	.irq_bus_setup		= pSeries_irq_bus_setup,
 	.restart		= rtas_restart,
 	.power_off		= rtas_power_off,
 	.halt			= rtas_halt,

arch/ppc64/kernel/pci.c

@@ -902,6 +902,9 @@ void __devinit pcibios_fixup_bus(struct pci_bus *bus)
 	list_for_each_entry(dev, &bus->devices, bus_list)
 		ppc_md.iommu_dev_setup(dev);
 
+	if (ppc_md.irq_bus_setup)
+		ppc_md.irq_bus_setup(bus);
+
 	if (!pci_probe_only)
 		return;
 

arch/ppc64/kernel/pci.h

@@ -40,10 +40,14 @@ struct device_node *fetch_dev_dn(struct pci_dev *dev);
 void pci_addr_cache_insert_device(struct pci_dev *dev);
 void pci_addr_cache_remove_device(struct pci_dev *dev);
 
-/* From pSeries_pci.h */
+/* From rtas_pci.h */
 void init_pci_config_tokens (void);
 unsigned long get_phb_buid (struct device_node *);
 
+/* From pSeries_pci.h */
+extern void pSeries_final_fixup(void);
+extern void pSeries_irq_bus_setup(struct pci_bus *bus);
+
 extern unsigned long pci_probe_only;
 extern unsigned long pci_assign_all_buses;
 extern int pci_read_irq_line(struct pci_dev *pci_dev);

include/asm-ppc64/machdep.h

@@ -76,6 +76,7 @@ struct machdep_calls {
 	void		(*tce_flush)(struct iommu_table *tbl);
 	void		(*iommu_dev_setup)(struct pci_dev *dev);
 	void		(*iommu_bus_setup)(struct pci_bus *bus);
+	void		(*irq_bus_setup)(struct pci_bus *bus);
 
 	int		(*probe)(int platform);
 	void		(*setup_arch)(void);