From mboxrd@z Thu Jan 1 00:00:00 1970 From: robh@kernel.org (Rob Herring) Date: Tue, 8 Dec 2015 14:44:15 -0600 Subject: [PATCH 1/4] ARM: versatile: add DT based PCI detection In-Reply-To: <1449607458-16850-1-git-send-email-robh@kernel.org> References: <1449607458-16850-1-git-send-email-robh@kernel.org> Message-ID: <1449607458-16850-2-git-send-email-robh@kernel.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.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 Cc: Russell King Cc: Linus Walleij --- arch/arm/mach-versatile/versatile_dt.c | 50 ++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) diff --git a/arch/arm/mach-versatile/versatile_dt.c b/arch/arm/mach-versatile/versatile_dt.c index 7de3e92..a585758 100644 --- a/arch/arm/mach-versatile/versatile_dt.c +++ b/arch/arm/mach-versatile/versatile_dt.c @@ -22,15 +22,65 @@ */ #include +#include +#include +#include #include #include +#include #include #include #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); } -- 2.5.0