bcm2835-aux: Add aux interrupt controller

The AUX block has a shared interrupt line with a register indicating
which devices have active IRQs. Expose this as a nested interrupt
controller to avoid sharing problems.

See: https://github.com/raspberrypi/linux/issues/1484
     https://github.com/raspberrypi/linux/issues/1573

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/clk/bcm/clk-bcm2835-aux.c b/drivers/clk/bcm/clk-bcm2835-aux.c
index bd750cf2238d61489811e7d7bd3b5f9950ed53c8..41e0702fae4692221980b0d02aed1ba652945650 100644 (file)
--- a/drivers/clk/bcm/clk-bcm2835-aux.c
+++ b/drivers/clk/bcm/clk-bcm2835-aux.c
@@ -17,17 +17,107 @@
 #include <linux/clk/bcm2835.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/of_irq.h>
 #include <dt-bindings/clock/bcm2835-aux.h>
 
 #define BCM2835_AUXIRQ         0x00
 #define BCM2835_AUXENB         0x04
 
+#define BCM2835_AUXIRQ_NUM_IRQS  3
+
+#define BCM2835_AUXIRQ_UART_IRQ  0
+#define BCM2835_AUXIRQ_SPI1_IRQ  1
+#define BCM2835_AUXIRQ_SPI2_IRQ  2
+
+#define BCM2835_AUXIRQ_UART_MASK 0x01
+#define BCM2835_AUXIRQ_SPI1_MASK 0x02
+#define BCM2835_AUXIRQ_SPI2_MASK 0x04
+
+#define BCM2835_AUXIRQ_ALL_MASK \
+       (BCM2835_AUXIRQ_UART_MASK | \
+        BCM2835_AUXIRQ_SPI1_MASK | \
+        BCM2835_AUXIRQ_SPI2_MASK)
+
+struct auxirq_state {
+       void __iomem      *status;
+       u32                enables;
+       struct irq_domain *domain;
+       struct regmap     *local_regmap;
+};
+
+static struct auxirq_state auxirq __read_mostly;
+
+static irqreturn_t bcm2835_auxirq_handler(int irq, void *dev_id)
+{
+       u32 stat = readl_relaxed(auxirq.status);
+       u32 masked = stat & auxirq.enables;
+
+       if (masked & BCM2835_AUXIRQ_UART_MASK)
+               generic_handle_irq(irq_linear_revmap(auxirq.domain,
+                                                    BCM2835_AUXIRQ_UART_IRQ));
+
+       if (masked & BCM2835_AUXIRQ_SPI1_MASK)
+               generic_handle_irq(irq_linear_revmap(auxirq.domain,
+                                                    BCM2835_AUXIRQ_SPI1_IRQ));
+
+       if (masked & BCM2835_AUXIRQ_SPI2_MASK)
+               generic_handle_irq(irq_linear_revmap(auxirq.domain,
+                                                    BCM2835_AUXIRQ_SPI2_IRQ));
+
+       return (masked & BCM2835_AUXIRQ_ALL_MASK) ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static int bcm2835_auxirq_xlate(struct irq_domain *d,
+                                struct device_node *ctrlr,
+                                const u32 *intspec, unsigned int intsize,
+                                unsigned long *out_hwirq,
+                                unsigned int *out_type)
+{
+       if (WARN_ON(intsize != 1))
+               return -EINVAL;
+
+       if (WARN_ON(intspec[0] >= BCM2835_AUXIRQ_NUM_IRQS))
+               return -EINVAL;
+
+       *out_hwirq = intspec[0];
+       *out_type = IRQ_TYPE_NONE;
+       return 0;
+}
+
+static void bcm2835_auxirq_mask(struct irq_data *data)
+{
+       irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+       auxirq.enables &= ~(1 << hwirq);
+}
+
+static void bcm2835_auxirq_unmask(struct irq_data *data)
+{
+       irq_hw_number_t hwirq = irqd_to_hwirq(data);
+
+       auxirq.enables |= (1 << hwirq);
+}
+
+static struct irq_chip bcm2835_auxirq_chip = {
+       .name = "bcm2835-auxirq",
+       .irq_mask = bcm2835_auxirq_mask,
+       .irq_unmask = bcm2835_auxirq_unmask,
+};
+
+static const struct irq_domain_ops bcm2835_auxirq_ops = {
+       .xlate = bcm2835_auxirq_xlate//irq_domain_xlate_onecell
+};
+
 static int bcm2835_aux_clk_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
+       struct device_node *node = dev->of_node;
        struct clk_hw_onecell_data *onecell;
        const char *parent;
        struct clk *parent_clk;
+       int parent_irq;
        struct resource *res;
        void __iomem *reg, *gate;
 
@@ -41,6 +131,36 @@ static int bcm2835_aux_clk_probe(struct platform_device *pdev)
        if (IS_ERR(reg))
                return PTR_ERR(reg);
 
+       parent_irq = irq_of_parse_and_map(node, 0);
+       if (parent_irq) {
+               int ret;
+               int i;
+
+               /* Manage the AUX irq as well */
+               auxirq.status = reg + BCM2835_AUXIRQ;
+               auxirq.domain = irq_domain_add_linear(node,
+                                                     BCM2835_AUXIRQ_NUM_IRQS,
+                                                     &bcm2835_auxirq_ops,
+                                                     NULL);
+               if (!auxirq.domain)
+                       return -ENXIO;
+
+               for (i = 0; i < BCM2835_AUXIRQ_NUM_IRQS; i++) {
+                       unsigned int irq = irq_create_mapping(auxirq.domain, i);
+
+                       if (irq == 0)
+                               return -ENXIO;
+
+                       irq_set_chip_and_handler(irq, &bcm2835_auxirq_chip,
+                                                handle_level_irq);
+               }
+
+               ret = devm_request_irq(dev, parent_irq, bcm2835_auxirq_handler,
+                                      0, "bcm2835-auxirq", NULL);
+               if (ret)
+                       return ret;
+       }
+
        onecell = devm_kmalloc(dev, sizeof(*onecell) + sizeof(*onecell->hws) *
                               BCM2835_AUX_CLOCK_COUNT, GFP_KERNEL);
        if (!onecell)