[PATCH] irqchip: bcm2835: Add FIQ support

Noralf Trønnes
2015-06-12T17:27:55Z

Add a duplicate irq range with an offset on the hwirq's so the
driver can detect that enable_fiq() is used.
Tested with downstream dwc_otg USB controller driver.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
---
arch/arm/mach-bcm/Kconfig | 1 +
drivers/irqchip/irq-bcm2835.c | 53 ++++++++++++++++++++++++++++++++++++++-----
2 files changed, 48 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
index 8b11f44..7cfef7b 100644
--- a/arch/arm/mach-bcm/Kconfig
+++ b/arch/arm/mach-bcm/Kconfig
@@ -114,6 +114,7 @@ config ARCH_BCM2835
select ARM_ERRATA_411920
select ARM_TIMER_SP804
select CLKSRC_OF
+ select FIQ
select PINCTRL
select PINCTRL_BCM2835
help
diff --git a/drivers/irqchip/irq-bcm2835.c b/drivers/irqchip/irq-bcm2835.c
index 5916d6c..db66246 100644
--- a/drivers/irqchip/irq-bcm2835.c
+++ b/drivers/irqchip/irq-bcm2835.c
@@ -56,7 +56,7 @@
#include "irqchip.h"

/* Put the bank and irq (32 bits) into the hwirq */
-#define MAKE_HWIRQ(b, n) ((b << 5) | (n))
+#define MAKE_HWIRQ(b, n) (((b) << 5) | (n))
#define HWIRQ_BANK(i) (i >> 5)
#define HWIRQ_BIT(i) BIT(i & 0x1f)

@@ -72,9 +72,13 @@
| SHORTCUT1_MASK | SHORTCUT2_MASK)

#define REG_FIQ_CONTROL 0x0c
+#define REG_FIQ_ENABLE 0x80
+#define REG_FIQ_DISABLE 0

#define NR_BANKS 3
#define IRQS_PER_BANK 32
+#define NUMBER_IRQS MAKE_HWIRQ(NR_BANKS, 0)
+#define FIQ_START (NR_IRQS_BANK0 + MAKE_HWIRQ(NR_BANKS - 1, 0))

static int reg_pending[] __initconst = { 0x00, 0x04, 0x08 };
static int reg_enable[] __initconst = { 0x18, 0x10, 0x14 };
@@ -98,14 +102,38 @@ static struct armctrl_ic intc __read_mostly;
static void __exception_irq_entry bcm2835_handle_irq(
struct pt_regs *regs);

+static inline unsigned int hwirq_to_fiq(unsigned long hwirq)
+{
+ hwirq -= NUMBER_IRQS;
+ /*
+ * The hwirq numbering used in this driver is:
+ * BASE (0-7) GPU1 (32-63) GPU2 (64-95).
+ * This differ from the one used in the FIQ register:
+ * GPU1 (0-31) GPU2 (32-63) BASE (64-71)
+ */
+ if (hwirq >= 32)
+ return hwirq - 32;
+
+ return hwirq + 64;
+}
+
static void armctrl_mask_irq(struct irq_data *d)
{
- writel_relaxed(HWIRQ_BIT(d->hwirq), intc.disable[HWIRQ_BANK(d->hwirq)]);
+ if (d->hwirq >= NUMBER_IRQS)
+ writel_relaxed(REG_FIQ_DISABLE, intc.base + REG_FIQ_CONTROL);
+ else
+ writel_relaxed(HWIRQ_BIT(d->hwirq),
+ intc.disable[HWIRQ_BANK(d->hwirq)]);
}

static void armctrl_unmask_irq(struct irq_data *d)
{
- writel_relaxed(HWIRQ_BIT(d->hwirq), intc.enable[HWIRQ_BANK(d->hwirq)]);
+ if (d->hwirq >= NUMBER_IRQS)
+ writel_relaxed(REG_FIQ_ENABLE | hwirq_to_fiq(d->hwirq),
+ intc.base + REG_FIQ_CONTROL);
+ else
+ writel_relaxed(HWIRQ_BIT(d->hwirq),
+ intc.enable[HWIRQ_BANK(d->hwirq)]);
}

static struct irq_chip armctrl_chip = {
@@ -150,8 +178,9 @@ static int __init armctrl_of_init(struct device_node *node,
panic("%s: unable to map IC registers\n",
node->full_name);

- intc.domain = irq_domain_add_linear(node, MAKE_HWIRQ(NR_BANKS, 0),
- &armctrl_ops, NULL);
+ intc.base = base;
+ intc.domain = irq_domain_add_linear(node, NUMBER_IRQS * 2,
+ &armctrl_ops, NULL);
if (!intc.domain)
panic("%s: unable to create IRQ domain\n", node->full_name);

@@ -168,8 +197,20 @@ static int __init armctrl_of_init(struct device_node *node,
set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
}
}
-
set_handle_irq(bcm2835_handle_irq);
+
+ /* Make a duplicate irq range which is used to enable FIQ */
+ for (b = 0; b < NR_BANKS; b++) {
+ for (i = 0; i < bank_irqs[b]; i++) {
+ irq = irq_create_mapping(intc.domain,
+ MAKE_HWIRQ(b, i) + NUMBER_IRQS);
+ BUG_ON(irq <= 0);
+ irq_set_chip(irq, &armctrl_chip);
+ set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
+ }
+ }
+ init_FIQ(FIQ_START);
+
return 0;
}

--
2.2.2