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Commit a8e2894c authored by Rob Herring's avatar Rob Herring Committed by Arnd Bergmann
Browse files

ARM: versatile: add DT based PCI detection 



Disable the Versatile PCI DT node when no PCI backplane is detected. This
will prevent the Versatile PCI driver from probing when PCI is not
populated.

Signed-off-by: default avatarRob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent 31ade3b8

arch/arm/mach-versatile/versatile_dt.c

+50 −0
Original line number Diff line number Diff line
@@ -22,15 +22,65 @@ 
 */



#include <linux/init.h>

#include <linux/io.h>

#include <linux/of.h>

#include <linux/of_address.h>

#include <linux/of_irq.h>

#include <linux/of_platform.h>

#include <linux/slab.h>

#include <asm/mach-types.h>

#include <asm/mach/arch.h>



#include "core.h"



#define VERSATILE_SYS_PCICTL_OFFSET           0x44

static void __iomem *versatile_sys_base;



static void __init versatile_dt_pci_init(void)

{

	u32 val;

	struct device_node *np;

	struct property *newprop;



	np = of_find_compatible_node(NULL, NULL, "arm,versatile-pci");

	if (!np)

		return;



	/* Check if PCI backplane is detected */

	val = readl(versatile_sys_base + VERSATILE_SYS_PCICTL_OFFSET);

	if (val & 1) {

		/*

		 * Enable PCI accesses. Note that the documentaton is

		 * inconsistent whether or not this is needed, but the old

		 * driver had it so we will keep it.

		 */

		writel(1, versatile_sys_base + VERSATILE_SYS_PCICTL_OFFSET);

		return;

	}



	newprop = kzalloc(sizeof(*newprop), GFP_KERNEL);

	if (!newprop)

		return;



	newprop->name = kstrdup("status", GFP_KERNEL);

	newprop->value = kstrdup("disabled", GFP_KERNEL);

	newprop->length = sizeof("disabled");

	of_update_property(np, newprop);



	pr_info("Not plugged into PCI backplane!\n");

}



static void __init versatile_dt_init(void)

{

	struct device_node *np;



	np = of_find_compatible_node(NULL, NULL, "arm,core-module-versatile");

	if (np)

		versatile_sys_base = of_iomap(np, 0);

	WARN_ON(!versatile_sys_base);



	versatile_dt_pci_init();



	of_platform_populate(NULL, of_default_bus_match_table,

			     versatile_auxdata_lookup, NULL);

}