pccard: configure CLS on attach

For non hotplug PCI devices, the system firmware usually configures
CLS correctly.  For pccard devices system firmware can't do it and
Linux PCI layer doesn't do it either.  Unfortunately this leads to
poor performance for certain devices (sata_sil).  Unless MWI, which
requires separate configuration, is to be used, CLS doesn't affect
correctness, so the configuration should be harmless.

This patch makes pci_set_cacheline_size() always built and export it
and make pccard call it during attach.

Please note that some other PCI hotplug drivers (shpchp and pciehp)
also configure CLS on hotplug.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Daniel Ritz <daniel.ritz@gmx.ch>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Greg KH <greg@kroah.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Cc: Axel Birndt <towerlexa@gmx.de>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 15 insertions, 8 deletions

diff --git a/drivers/pcmcia/cardbus.c b/drivers/pcmcia/cardbus.c
index db77e1f3309..98789c031a7 100644
--- a/drivers/pcmcia/cardbus.c
+++ b/drivers/pcmcia/cardbus.c
@@ -184,26 +184,33 @@ fail:
     
 =====================================================================*/
 
-/*
- * Since there is only one interrupt available to CardBus
- * devices, all devices downstream of this device must
- * be using this IRQ.
- */
-static void cardbus_assign_irqs(struct pci_bus *bus, int irq)
+static void cardbus_config_irq_and_cls(struct pci_bus *bus, int irq)
 {
 	struct pci_dev *dev;
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		u8 irq_pin;
 
+		/*
+		 * Since there is only one interrupt available to
+		 * CardBus devices, all devices downstream of this
+		 * device must be using this IRQ.
+		 */
 		pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &irq_pin);
 		if (irq_pin) {
 			dev->irq = irq;
 			pci_write_config_byte(dev, PCI_INTERRUPT_LINE, dev->irq);
 		}
 
+		/*
+		 * Some controllers transfer very slowly with 0 CLS.
+		 * Configure it.  This may fail as CLS configuration
+		 * is mandatory only for MWI.
+		 */
+		pci_set_cacheline_size(dev);
+
 		if (dev->subordinate)
-			cardbus_assign_irqs(dev->subordinate, irq);
+			cardbus_config_irq_and_cls(dev->subordinate, irq);
 	}
 }
 
@@ -228,7 +235,7 @@ int __ref cb_alloc(struct pcmcia_socket * s)
 	 */
 	pci_bus_size_bridges(bus);
 	pci_bus_assign_resources(bus);
-	cardbus_assign_irqs(bus, s->pci_irq);
+	cardbus_config_irq_and_cls(bus, s->pci_irq);
 
 	/* socket specific tune function */
 	if (s->tune_bridge)