s390/pci: add parameter to force floating irqs

Provide a kernel parameter to force the usage of floating interrupts.

Signed-off-by: Sebastian Ott <sebott@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2b8ee90..abc1b6e 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3394,6 +3394,7 @@
                                bridges without forcing it upstream. Note:
                                this removes isolation between devices and
                                may put more devices in an IOMMU group.
+               force_floating  [S390] Force usage of floating interrupts.
 
        pcie_aspm=      [PCIE] Forcibly enable or disable PCIe Active State Power
                        Management.

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index a285754..3280132 100644 (file)
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -163,6 +163,7 @@ static inline bool zdev_enabled(struct zpci_dev *zdev)
 }
 
 extern const struct attribute_group *zpci_attr_groups[];
+extern unsigned int s390_pci_force_floating __initdata;
 
 /* -----------------------------------------------------------------------------
   Prototypes

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 716e773..db096fd 100644 (file)
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -741,6 +741,7 @@ static void zpci_mem_exit(void)
 }
 
 static unsigned int s390_pci_probe __initdata = 1;
+unsigned int s390_pci_force_floating __initdata;
 static unsigned int s390_pci_initialized;
 
 char * __init pcibios_setup(char *str)
@@ -749,6 +750,10 @@ char * __init pcibios_setup(char *str)
                s390_pci_probe = 0;
                return NULL;
        }
+       if (!strcmp(str, "force_floating")) {
+               s390_pci_force_floating = 1;
+               return NULL;
+       }
        return str;
 }
 

diff --git a/arch/s390/pci/pci_irq.c b/arch/s390/pci/pci_irq.c
index c73ab85..d80616a 100644 (file)
--- a/arch/s390/pci/pci_irq.c
+++ b/arch/s390/pci/pci_irq.c
@@ -433,6 +433,9 @@ int __init zpci_irq_init(void)
        int rc;
 
        irq_delivery = sclp.has_dirq ? DIRECTED : FLOATING;
+       if (s390_pci_force_floating)
+               irq_delivery = FLOATING;
+
        if (irq_delivery == DIRECTED)
                zpci_airq.handler = zpci_directed_irq_handler;