Commit 56271303 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
Browse files

s390/pci: add parameter to disable usage of MIO instructions 



Allow users to disable usage of MIO instructions by specifying pci=nomio
at the kernel command line.

Signed-off-by: default avatarSebastian Ott <sebott@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 71ba41c9

Documentation/admin-guide/kernel-parameters.txt

+1 −0
Original line number Diff line number Diff line
@@ -3395,6 +3395,7 @@ 
				this removes isolation between devices and

				may put more devices in an IOMMU group.

		force_floating	[S390] Force usage of floating interrupts.

		nomio		[S390] Do not use MIO instructions.



	pcie_aspm=	[PCIE] Forcibly enable or disable PCIe Active State Power

			Management.

arch/s390/pci/pci.c

+6 −1
Original line number Diff line number Diff line
@@ -850,6 +850,7 @@ static void zpci_mem_exit(void) 
}



static unsigned int s390_pci_probe __initdata = 1;

static unsigned int s390_pci_no_mio __initdata;

unsigned int s390_pci_force_floating __initdata;

static unsigned int s390_pci_initialized;
@@ -859,6 +860,10 @@ char * __init pcibios_setup(char *str) 
		s390_pci_probe = 0;

		return NULL;

	}

	if (!strcmp(str, "nomio")) {

		s390_pci_no_mio = 1;

		return NULL;

	}

	if (!strcmp(str, "force_floating")) {

		s390_pci_force_floating = 1;

		return NULL;
@@ -881,7 +886,7 @@ static int __init pci_base_init(void) 
	if (!test_facility(69) || !test_facility(71))

		return 0;



	if (test_facility(153))

	if (test_facility(153) && !s390_pci_no_mio)

		static_branch_enable(&have_mio);



	rc = zpci_debug_init();