summaryrefslogtreecommitdiff
path: root/drivers
diff options
context:
space:
mode:
authorSricharan R <r.sricharan@ti.com>2013-12-03 14:27:23 +0400
committerSricharan R <r.sricharan@ti.com>2014-02-05 18:38:34 +0400
commit96ca848ef7ea1be7e92d1cceb34ef3aa86053828 (patch)
treee57b452cb1a6f383f5c9dcc346bf53e062ced0da /drivers
parent006e983bbc805431c44e2135e13841f66059a045 (diff)
downloadlinux-96ca848ef7ea1be7e92d1cceb34ef3aa86053828.tar.xz
DRIVERS: IRQCHIP: CROSSBAR: Add support for Crossbar IP
Some socs have a large number of interrupts requests to service the needs of its many peripherals and subsystems. All of the interrupt lines from the subsystems are not needed at the same time, so they have to be muxed to the irq-controller appropriately. In such places a interrupt controllers are preceded by an CROSSBAR that provides flexibility in muxing the device requests to the controller inputs. This driver takes care a allocating a free irq and then configuring the crossbar IP as a part of the mpu's irqchip callbacks. crossbar_init should be called right before the irqchip_init, so that it is setup to handle the irqchip callbacks. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Tony Lindgren <tony@atomide.com> Cc: Rajendra Nayak <rnayak@ti.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Herring <rob.herring@calxeda.com> Signed-off-by: Sricharan R <r.sricharan@ti.com> Acked-by: Kumar Gala <galak@codeaurora.org> (for DT binding portion) Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/irqchip/Kconfig8
-rw-r--r--drivers/irqchip/Makefile1
-rw-r--r--drivers/irqchip/irq-crossbar.c208
3 files changed, 217 insertions, 0 deletions
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 61ffdca96e25..111068782da4 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -69,3 +69,11 @@ config VERSATILE_FPGA_IRQ_NR
config XTENSA_MX
bool
select IRQ_DOMAIN
+
+config IRQ_CROSSBAR
+ bool
+ help
+ Support for a CROSSBAR ip that preceeds the main interrupt controller.
+ The primary irqchip invokes the crossbar's callback which inturn allocates
+ a free irq and configures the IP. Thus the peripheral interrupts are
+ routed to one of the free irqchip interrupt lines.
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 86b484cb3ec2..3e776cb8dd46 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_ARCH_VT8500) += irq-vt8500.o
obj-$(CONFIG_TB10X_IRQC) += irq-tb10x.o
obj-$(CONFIG_XTENSA) += irq-xtensa-pic.o
obj-$(CONFIG_XTENSA_MX) += irq-xtensa-mx.o
+obj-$(CONFIG_IRQ_CROSSBAR) += irq-crossbar.o
diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
new file mode 100644
index 000000000000..fc817d28d1fe
--- /dev/null
+++ b/drivers/irqchip/irq-crossbar.c
@@ -0,0 +1,208 @@
+/*
+ * drivers/irqchip/irq-crossbar.c
+ *
+ * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
+ * Author: Sricharan R <r.sricharan@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/slab.h>
+#include <linux/irqchip/arm-gic.h>
+
+#define IRQ_FREE -1
+#define GIC_IRQ_START 32
+
+/*
+ * @int_max: maximum number of supported interrupts
+ * @irq_map: array of interrupts to crossbar number mapping
+ * @crossbar_base: crossbar base address
+ * @register_offsets: offsets for each irq number
+ */
+struct crossbar_device {
+ uint int_max;
+ uint *irq_map;
+ void __iomem *crossbar_base;
+ int *register_offsets;
+ void (*write) (int, int);
+};
+
+static struct crossbar_device *cb;
+
+static inline void crossbar_writel(int irq_no, int cb_no)
+{
+ writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
+}
+
+static inline void crossbar_writew(int irq_no, int cb_no)
+{
+ writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
+}
+
+static inline void crossbar_writeb(int irq_no, int cb_no)
+{
+ writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
+}
+
+static inline int allocate_free_irq(int cb_no)
+{
+ int i;
+
+ for (i = 0; i < cb->int_max; i++) {
+ if (cb->irq_map[i] == IRQ_FREE) {
+ cb->irq_map[i] = cb_no;
+ return i;
+ }
+ }
+
+ return -ENODEV;
+}
+
+static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hw)
+{
+ cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
+ return 0;
+}
+
+static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
+{
+ irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
+
+ if (hw > GIC_IRQ_START)
+ cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
+}
+
+static int crossbar_domain_xlate(struct irq_domain *d,
+ struct device_node *controller,
+ const u32 *intspec, unsigned int intsize,
+ unsigned long *out_hwirq,
+ unsigned int *out_type)
+{
+ unsigned long ret;
+
+ ret = allocate_free_irq(intspec[1]);
+
+ if (IS_ERR_VALUE(ret))
+ return ret;
+
+ *out_hwirq = ret + GIC_IRQ_START;
+ return 0;
+}
+
+const struct irq_domain_ops routable_irq_domain_ops = {
+ .map = crossbar_domain_map,
+ .unmap = crossbar_domain_unmap,
+ .xlate = crossbar_domain_xlate
+};
+
+static int __init crossbar_of_init(struct device_node *node)
+{
+ int i, size, max, reserved = 0, entry;
+ const __be32 *irqsr;
+
+ cb = kzalloc(sizeof(struct cb_device *), GFP_KERNEL);
+
+ if (!cb)
+ return -ENOMEM;
+
+ cb->crossbar_base = of_iomap(node, 0);
+ if (!cb->crossbar_base)
+ goto err1;
+
+ of_property_read_u32(node, "ti,max-irqs", &max);
+ cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL);
+ if (!cb->irq_map)
+ goto err2;
+
+ cb->int_max = max;
+
+ for (i = 0; i < max; i++)
+ cb->irq_map[i] = IRQ_FREE;
+
+ /* Get and mark reserved irqs */
+ irqsr = of_get_property(node, "ti,irqs-reserved", &size);
+ if (irqsr) {
+ size /= sizeof(__be32);
+
+ for (i = 0; i < size; i++) {
+ of_property_read_u32_index(node,
+ "ti,irqs-reserved",
+ i, &entry);
+ if (entry > max) {
+ pr_err("Invalid reserved entry\n");
+ goto err3;
+ }
+ cb->irq_map[entry] = 0;
+ }
+ }
+
+ cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL);
+ if (!cb->register_offsets)
+ goto err3;
+
+ of_property_read_u32(node, "ti,reg-size", &size);
+
+ switch (size) {
+ case 1:
+ cb->write = crossbar_writeb;
+ break;
+ case 2:
+ cb->write = crossbar_writew;
+ break;
+ case 4:
+ cb->write = crossbar_writel;
+ break;
+ default:
+ pr_err("Invalid reg-size property\n");
+ goto err4;
+ break;
+ }
+
+ /*
+ * Register offsets are not linear because of the
+ * reserved irqs. so find and store the offsets once.
+ */
+ for (i = 0; i < max; i++) {
+ if (!cb->irq_map[i])
+ continue;
+
+ cb->register_offsets[i] = reserved;
+ reserved += size;
+ }
+
+ register_routable_domain_ops(&routable_irq_domain_ops);
+ return 0;
+
+err4:
+ kfree(cb->register_offsets);
+err3:
+ kfree(cb->irq_map);
+err2:
+ iounmap(cb->crossbar_base);
+err1:
+ kfree(cb);
+ return -ENOMEM;
+}
+
+static const struct of_device_id crossbar_match[] __initconst = {
+ { .compatible = "ti,irq-crossbar" },
+ {}
+};
+
+int __init irqcrossbar_init(void)
+{
+ struct device_node *np;
+ np = of_find_matching_node(NULL, crossbar_match);
+ if (!np)
+ return -ENODEV;
+
+ crossbar_of_init(np);
+ return 0;
+}