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ARM: versatile: add DT based PCI detection

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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: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This commit is contained in:
Rob Herring 2015-12-08 14:44:15 -06:00 • committed by Arnd Bergmann
parent 31ade3b83e
commit a8e2894c12
1 changed files with 50 additions and 0 deletions
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50
arch/arm/mach-versatile/versatile_dt.c
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@ -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);
}