irqchip: irq-bcm2836: Remove regmap and syscon use

The syscon node defines a register range that duplicates that used by
the local_intc node on bcm2836/7. Since irq-bcm2835 and irq-bcm2836 are
built in and always present together (both drivers are enabled by
CONFIG_ARCH_BCM2835), it is possible to replace the syscon usage with a
global variable that simplifies the code. Doing so does lose the
locking provided by regmap, but as only one side is using the regmap
interface (irq-bcm2835 uses readl and write) there is no loss of
atomicity.

See: https://github.com/raspberrypi/firmware/issues/926

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

diff --git a/drivers/irqchip/irq-bcm2835.c b/drivers/irqchip/irq-bcm2835.c
index a6ffff7..e08c209 100644 (file)
--- a/drivers/irqchip/irq-bcm2835.c
+++ b/drivers/irqchip/irq-bcm2835.c
@@ -41,8 +41,6 @@
 #include <linux/of_irq.h>
 #include <linux/irqchip.h>
 #include <linux/irqdomain.h>
-#include <linux/mfd/syscon.h>
-#include <linux/regmap.h>
 
 #include <asm/exception.h>
 #include <asm/mach/irq.h>
@@ -92,7 +90,7 @@ struct armctrl_ic {
        void __iomem *enable[NR_BANKS];
        void __iomem *disable[NR_BANKS];
        struct irq_domain *domain;
-       struct regmap *local_regmap;
+       void __iomem *local_base;
 };
 
 static struct armctrl_ic intc __read_mostly;
@@ -129,24 +127,20 @@ static void armctrl_unmask_irq(struct irq_data *d)
        if (d->hwirq >= NUMBER_IRQS) {
                if (num_online_cpus() > 1) {
                        unsigned int data;
-                       int ret;
 
-                       if (!intc.local_regmap) {
-                               pr_err("FIQ is disabled due to missing regmap\n");
+                       if (!intc.local_base) {
+                               pr_err("FIQ is disabled due to missing arm_local_intc\n");
                                return;
                        }
 
-                       ret = regmap_read(intc.local_regmap,
-                                         ARM_LOCAL_GPU_INT_ROUTING, &data);
-                       if (ret) {
-                               pr_err("Failed to read int routing %d\n", ret);
-                               return;
-                       }
+                       data = readl_relaxed(intc.local_base +
+                                            ARM_LOCAL_GPU_INT_ROUTING);
 
                        data &= ~0xc;
                        data |= (1 << 2);
-                       regmap_write(intc.local_regmap,
-                                    ARM_LOCAL_GPU_INT_ROUTING, data);
+                       writel_relaxed(data,
+                                      intc.local_base +
+                                      ARM_LOCAL_GPU_INT_ROUTING);
                }
 
                writel_relaxed(REG_FIQ_ENABLE | hwirq_to_fiq(d->hwirq),
@@ -246,12 +240,10 @@ static int __init armctrl_of_init(struct device_node *node,
        }
 
        if (is_2836) {
-               intc.local_regmap =
-                       syscon_regmap_lookup_by_compatible("brcm,bcm2836-arm-local");
-               if (IS_ERR(intc.local_regmap)) {
-                       pr_err("Failed to get local register map. FIQ is disabled for cpus > 1\n");
-                       intc.local_regmap = NULL;
-               }
+               extern void __iomem * __attribute__((weak)) arm_local_intc;
+               intc.local_base = arm_local_intc;
+               if (!intc.local_base)
+                       pr_err("Failed to get local intc base. FIQ is disabled for cpus > 1\n");
        }
 
        /* Make a duplicate irq range which is used to enable FIQ */

diff --git a/drivers/irqchip/irq-bcm2836.c b/drivers/irqchip/irq-bcm2836.c
index b6a7036..867c3b4 100644 (file)
--- a/drivers/irqchip/irq-bcm2836.c
+++ b/drivers/irqchip/irq-bcm2836.c
@@ -22,6 +22,9 @@ struct bcm2836_arm_irqchip_intc {
 
 static struct bcm2836_arm_irqchip_intc intc  __read_mostly;
 
+void __iomem *arm_local_intc;
+EXPORT_SYMBOL_GPL(arm_local_intc);
+
 static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
                                                 unsigned int bit,
                                                 int cpu)
@@ -323,6 +326,8 @@ static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
                panic("%pOF: unable to map local interrupt registers\n", node);
        }
 
+       arm_local_intc = intc.base;
+
        bcm2835_init_local_timer_frequency();
 
        intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,