[PATCH 3/9] ARM: versatile: add DT based PCI detection

Rob Herring
2014-12-30T19:28:32Z

From: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

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-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
Cc: Linus Walleij <linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
arch/arm/mach-versatile/versatile_dt.c | 46 ++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)

diff --git a/arch/arm/mach-versatile/versatile_dt.c b/arch/arm/mach-versatile/versatile_dt.c
index 9f9bc61..5053810 100644
--- a/arch/arm/mach-versatile/versatile_dt.c
+++ b/arch/arm/mach-versatile/versatile_dt.c
@@ -22,15 +22,61 @@
*/

#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 __init versatile_dt_pci_init(void)
+{
+ u32 val;
+ void __iomem *base;
+ struct device_node *np;
+ struct property *newprop;
+
+ np = of_find_compatible_node(NULL, NULL, "arm,core-module-versatile");
+ if (!np)
+ return;
+
+ base = of_iomap(np, 0);
+ if (!base)
+ return;
+
+ /* Check if PCI backplane is detected */
+ val = __raw_readl(base + VERSATILE_SYS_PCICTL_OFFSET);
+ if (val & 1)
+ goto err;
+
+ np = of_find_compatible_node(NULL, NULL, "arm,versatile-pci");
+ if (!np)
+ goto err;
+
+ newprop = kzalloc(sizeof(*newprop), GFP_KERNEL);
+ if (!newprop)
+ goto err;
+
+ 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");
+err:
+ iounmap(base);
+}
+
static void __init versatile_dt_init(void)
{
+ versatile_dt_pci_init();
+
of_platform_populate(NULL, of_default_bus_match_table,
versatile_auxdata_lookup, NULL);
}
--
2.1.0