[PATCH v3 14/17] xtensa: add MX irqchip

Max Filippov
2013-12-01T08:05:21Z

MX is an interrupt distributor used in some SMP-capable xtensa
configurations.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
Changes v2 -> v3:
- update compatible string for MX irqchip

Changes v1 -> v2:
- don't disable preemption in the else clause of xtensa_mx_irq_[un]mask
as these functions should be always called with preemption disabled.

arch/xtensa/include/asm/irq.h | 1 +
arch/xtensa/include/asm/mxregs.h | 46 ++++++++++
arch/xtensa/include/asm/processor.h | 20 +++++
arch/xtensa/kernel/irq.c | 8 ++
drivers/irqchip/Kconfig | 4 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-xtensa-mx.c | 164 ++++++++++++++++++++++++++++++++++++
include/linux/irqchip/xtensa-mx.h | 17 ++++
8 files changed, 261 insertions(+)
create mode 100644 arch/xtensa/include/asm/mxregs.h
create mode 100644 drivers/irqchip/irq-xtensa-mx.c
create mode 100644 include/linux/irqchip/xtensa-mx.h

diff --git a/arch/xtensa/include/asm/irq.h b/arch/xtensa/include/asm/irq.h
index 16464f2..7d194d4 100644
--- a/arch/xtensa/include/asm/irq.h
+++ b/arch/xtensa/include/asm/irq.h
@@ -50,5 +50,6 @@ int xtensa_irq_domain_xlate(const u32 *intspec, unsigned int intsize,
unsigned long *out_hwirq, unsigned int *out_type);
int xtensa_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw);
unsigned xtensa_map_ext_irq(unsigned ext_irq);
+unsigned xtensa_get_ext_irq_no(unsigned irq);

#endif /* _XTENSA_IRQ_H */
diff --git a/arch/xtensa/include/asm/mxregs.h b/arch/xtensa/include/asm/mxregs.h
new file mode 100644
index 0000000..73dcc54
--- /dev/null
+++ b/arch/xtensa/include/asm/mxregs.h
@@ -0,0 +1,46 @@
+/*
+ * Xtensa MX interrupt distributor
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2008 - 2013 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_MXREGS_H
+#define _XTENSA_MXREGS_H
+
+/*
+ * RER/WER at, as Read/write external register
+ * at: value
+ * as: address
+ *
+ * Address Value
+ * 00nn 0...0p..p Interrupt Routing, route IRQ n to processor p
+ * 01pp 0...0d..d 16 bits (d) 'ored' as single IPI to processor p
+ * 0180 0...0m..m Clear enable specified by mask (m)
+ * 0184 0...0m..m Set enable specified by mask (m)
+ * 0190 0...0x..x 8-bit IPI partition register
+ * VVVVVVVVPPPPUUUUUUUUUUUUUUUUU
+ * V (10-bit) Release/Version
+ * P ( 4-bit) Number of cores - 1
+ * U (18-bit) ID
+ * 01a0 i.......i 32-bit ConfigID
+ * 0200 0...0m..m RunStall core 'n'
+ * 0220 c Cache coherency enabled
+ */
+
+#define MIROUT(irq) (0x000 + (irq))
+#define MIPICAUSE(cpu) (0x100 + (cpu))
+#define MIPISET(cause) (0x140 + (cause))
+#define MIENG 0x180
+#define MIENGSET 0x184
+#define MIASG 0x188 /* Read Global Assert Register */
+#define MIASGSET 0x18c /* Set Global Addert Regiter */
+#define MIPIPART 0x190
+#define SYSCFGID 0x1a0
+#define MPSCORE 0x200
+#define CCON 0x220
+
+#endif /* _XTENSA_MXREGS_H */
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index 7e409a5..abb5970 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -191,5 +191,25 @@ extern unsigned long get_wchan(struct task_struct *p);
#define set_sr(x,sr) ({unsigned int v=(unsigned int)x; WSR(v,sr);})
#define get_sr(sr) ({unsigned int v; RSR(v,sr); v; })

+#ifndef XCHAL_HAVE_EXTERN_REGS
+#define XCHAL_HAVE_EXTERN_REGS 0
+#endif
+
+#if XCHAL_HAVE_EXTERN_REGS
+
+static inline void set_er(unsigned long value, unsigned long addr)
+{
+ asm volatile ("wer %0, %1" : : "a" (value), "a" (addr) : "memory");
+}
+
+static inline unsigned long get_er(unsigned long addr)
+{
+ register unsigned long value;
+ asm volatile ("rer %0, %1" : "=a" (value) : "a" (addr) : "memory");
+ return value;
+}
+
+#endif /* XCHAL_HAVE_EXTERN_REGS */
+
#endif /* __ASSEMBLY__ */
#endif /* _XTENSA_PROCESSOR_H */
diff --git a/arch/xtensa/kernel/irq.c b/arch/xtensa/kernel/irq.c
index 3cef58e..7d49730 100644
--- a/arch/xtensa/kernel/irq.c
+++ b/arch/xtensa/kernel/irq.c
@@ -123,6 +123,14 @@ unsigned xtensa_map_ext_irq(unsigned ext_irq)
return XCHAL_NUM_INTERRUPTS;
}

+unsigned xtensa_get_ext_irq_no(unsigned irq)
+{
+ unsigned mask = (XCHAL_INTTYPE_MASK_EXTERN_EDGE |
+ XCHAL_INTTYPE_MASK_EXTERN_LEVEL) &
+ ((1u << irq) - 1);
+ return hweight32(mask);
+}
+
void __init init_IRQ(void)
{
#ifdef CONFIG_OF
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 3792a1a..07bc79c 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -61,3 +61,7 @@ config VERSATILE_FPGA_IRQ_NR
int
default 4
depends on VERSATILE_FPGA_IRQ
+
+config XTENSA_MX
+ bool
+ select IRQ_DOMAIN
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index c81a7f3..66913f9 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_VERSATILE_FPGA_IRQ) += irq-versatile-fpga.o
obj-$(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
diff --git a/drivers/irqchip/irq-xtensa-mx.c b/drivers/irqchip/irq-xtensa-mx.c
new file mode 100644
index 0000000..f693f1b
--- /dev/null
+++ b/drivers/irqchip/irq-xtensa-mx.c
@@ -0,0 +1,164 @@
+/*
+ * Xtensa MX interrupt distributor
+ *
+ * Copyright (C) 2002 - 2013 Tensilica, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+
+#include <asm/mxregs.h>
+
+#include "irqchip.h"
+
+#define HW_IRQ_IPI_COUNT 2
+#define HW_IRQ_MX_BASE 2
+#define HW_IRQ_EXTERN_BASE 3
+
+static DEFINE_PER_CPU(unsigned int, cached_irq_mask);
+
+static int xtensa_mx_irq_map(struct irq_domain *d, unsigned int irq,
+ irq_hw_number_t hw)
+{
+ if (hw < HW_IRQ_IPI_COUNT) {
+ struct irq_chip *irq_chip = d->host_data;
+ irq_set_chip_and_handler_name(irq, irq_chip,
+ handle_percpu_irq, "ipi");
+ irq_set_status_flags(irq, IRQ_LEVEL);
+ return 0;
+ }
+ return xtensa_irq_map(d, irq, hw);
+}
+
+/*
+ * Device Tree IRQ specifier translation function which works with one or
+ * two cell bindings. First cell value maps directly to the hwirq number.
+ * Second cell if present specifies whether hwirq number is external (1) or
+ * internal (0).
+ */
+static int xtensa_mx_irq_domain_xlate(struct irq_domain *d,
+ struct device_node *ctrlr,
+ const u32 *intspec, unsigned int intsize,
+ unsigned long *out_hwirq, unsigned int *out_type)
+{
+ return xtensa_irq_domain_xlate(intspec, intsize,
+ intspec[0], intspec[0] + HW_IRQ_EXTERN_BASE,
+ out_hwirq, out_type);
+}
+
+static const struct irq_domain_ops xtensa_mx_irq_domain_ops = {
+ .xlate = xtensa_mx_irq_domain_xlate,
+ .map = xtensa_mx_irq_map,
+};
+
+void secondary_init_irq(void)
+{
+ __this_cpu_write(cached_irq_mask,
+ XCHAL_INTTYPE_MASK_EXTERN_EDGE |
+ XCHAL_INTTYPE_MASK_EXTERN_LEVEL);
+ set_sr(XCHAL_INTTYPE_MASK_EXTERN_EDGE |
+ XCHAL_INTTYPE_MASK_EXTERN_LEVEL, intenable);
+}
+
+static void xtensa_mx_irq_mask(struct irq_data *d)
+{
+ unsigned int mask = 1u << d->hwirq;
+
+ if (mask & (XCHAL_INTTYPE_MASK_EXTERN_EDGE |
+ XCHAL_INTTYPE_MASK_EXTERN_LEVEL)) {
+ set_er(1u << (xtensa_get_ext_irq_no(d->hwirq) -
+ HW_IRQ_MX_BASE), MIENG);
+ } else {
+ mask = __this_cpu_read(cached_irq_mask) & ~mask;
+ __this_cpu_write(cached_irq_mask, mask);
+ set_sr(mask, intenable);
+ }
+}
+
+static void xtensa_mx_irq_unmask(struct irq_data *d)
+{
+ unsigned int mask = 1u << d->hwirq;
+
+ if (mask & (XCHAL_INTTYPE_MASK_EXTERN_EDGE |
+ XCHAL_INTTYPE_MASK_EXTERN_LEVEL)) {
+ set_er(1u << (xtensa_get_ext_irq_no(d->hwirq) -
+ HW_IRQ_MX_BASE), MIENGSET);
+ } else {
+ mask |= __this_cpu_read(cached_irq_mask);
+ __this_cpu_write(cached_irq_mask, mask);
+ set_sr(mask, intenable);
+ }
+}
+
+static void xtensa_mx_irq_enable(struct irq_data *d)
+{
+ variant_irq_enable(d->hwirq);
+ xtensa_mx_irq_unmask(d);
+}
+
+static void xtensa_mx_irq_disable(struct irq_data *d)
+{
+ xtensa_mx_irq_mask(d);
+ variant_irq_disable(d->hwirq);
+}
+
+static void xtensa_mx_irq_ack(struct irq_data *d)
+{
+ set_sr(1 << d->hwirq, intclear);
+}
+
+static int xtensa_mx_irq_retrigger(struct irq_data *d)
+{
+ set_sr(1 << d->hwirq, intset);
+ return 1;
+}
+
+static int xtensa_mx_irq_set_affinity(struct irq_data *d,
+ const struct cpumask *dest, bool force)
+{
+ unsigned mask = 1u << cpumask_any(dest);
+
+ set_er(mask, MIROUT(d->hwirq - HW_IRQ_MX_BASE));
+ return 0;
+
+}
+
+static struct irq_chip xtensa_mx_irq_chip = {
+ .name = "xtensa-mx",
+ .irq_enable = xtensa_mx_irq_enable,
+ .irq_disable = xtensa_mx_irq_disable,
+ .irq_mask = xtensa_mx_irq_mask,
+ .irq_unmask = xtensa_mx_irq_unmask,
+ .irq_ack = xtensa_mx_irq_ack,
+ .irq_retrigger = xtensa_mx_irq_retrigger,
+ .irq_set_affinity = xtensa_mx_irq_set_affinity,
+};
+
+int __init xtensa_mx_init_legacy(struct device_node *interrupt_parent)
+{
+ struct irq_domain *root_domain =
+ irq_domain_add_legacy(NULL, NR_IRQS, 0, 0,
+ &xtensa_mx_irq_domain_ops,
+ &xtensa_mx_irq_chip);
+ irq_set_default_host(root_domain);
+ secondary_init_irq();
+ return 0;
+}
+
+static int __init xtensa_mx_init(struct device_node *np,
+ struct device_node *interrupt_parent)
+{
+ struct irq_domain *root_domain =
+ irq_domain_add_linear(np, NR_IRQS, &xtensa_mx_irq_domain_ops,
+ &xtensa_mx_irq_chip);
+ irq_set_default_host(root_domain);
+ secondary_init_irq();
+ return 0;
+}
+IRQCHIP_DECLARE(xtensa_mx_irq_chip, "cdns,xtensa-mx", xtensa_mx_init);
diff --git a/include/linux/irqchip/xtensa-mx.h b/include/linux/irqchip/xtensa-mx.h
new file mode 100644
index 0000000..9c3b6ec
--- /dev/null
+++ b/include/linux/irqchip/xtensa-mx.h
@@ -0,0 +1,17 @@
+/*
+ * Xtensa MX interrupt distributor
+ *
+ * Copyright (C) 2002 - 2013 Tensilica, Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#ifndef __LINUX_IRQCHIP_XTENSA_MX_H
+#define __LINUX_IRQCHIP_XTENSA_MX_H
+
+struct device_node;
+int xtensa_mx_init_legacy(struct device_node *interrupt_parent);
+
+#endif /* __LINUX_IRQCHIP_XTENSA_MX_H */
--
1.8.1.4