The LS1021A allows inverting the polarity of six interrupt lines
IRQ[0:5] via the scfg_intpcr register, effectively allowing
IRQ_TYPE_LEVEL_LOW and IRQ_TYPE_EDGE_FALLING for those. We just need to
check the type, set the relevant bit in INTPCR accordingly, and fixup
the type argument before calling the GIC's irq_set_type.
In fact, the power-on-reset value of the INTPCR register on the LS1021A
is so that all six lines have their polarity inverted. Hence any
hardware connected to those lines is unusable without this: If the line
is indeed active low, the generic GIC code will reject an irq spec with
IRQ_TYPE_LEVEL_LOW, while if the line is active high, we must obviously
disable the polarity inversion (writing 0 to the relevant bit) before
unmasking the interrupt.
Some other Layerscape SOCs (LS1043A, LS1046A) have a similar feature,
just with a different number of external interrupt lines (and a
different POR value for the INTPCR register). This driver should be
prepared for supporting those by properly filling out the device tree
node. I have the reference manuals for all three boards, but I've only
tested the driver on an LS1021A.
Unfortunately, the Kconfig symbol ARCH_LAYERSCAPE only exists on
arm64, so do as is done for irq-ls-scfg-msi.c: introduce a new symbol
which is set when either ARCH_LAYERSCAPE or SOC_LS1021A is set.
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
drivers/irqchip/Kconfig | 4 +
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-ls-extirq.c | 197 ++++++++++++++++++++++++++++++++
3 files changed, 202 insertions(+)
create mode 100644 drivers/irqchip/irq-ls-extirq.c
diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index ccbb8973a324..bbb323462912 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -370,6 +370,10 @@ config MVEBU_PIC
config MVEBU_SEI
bool
+config LS_EXTIRQ
+ def_bool y if SOC_LS1021A || ARCH_LAYERSCAPE
+ select MFD_SYSCON
+
config LS_SCFG_MSI
def_bool y if SOC_LS1021A || ARCH_LAYERSCAPE
depends on PCI && PCI_MSI
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index cc7c43932f16..e806dda690ea 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_MVEBU_ICU) += irq-mvebu-icu.o
obj-$(CONFIG_MVEBU_ODMI) += irq-mvebu-odmi.o
obj-$(CONFIG_MVEBU_PIC) += irq-mvebu-pic.o
obj-$(CONFIG_MVEBU_SEI) += irq-mvebu-sei.o
+obj-$(CONFIG_LS_EXTIRQ) += irq-ls-extirq.o
obj-$(CONFIG_LS_SCFG_MSI) += irq-ls-scfg-msi.o
obj-$(CONFIG_EZNPS_GIC) += irq-eznps.o
obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o irq-aspeed-i2c-ic.o
diff --git a/drivers/irqchip/irq-ls-extirq.c b/drivers/irqchip/irq-ls-extirq.c
new file mode 100644
index 000000000000..4d1179fed77c
--- /dev/null
+++ b/drivers/irqchip/irq-ls-extirq.c
@@ -0,0 +1,197 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) "irq-ls-extirq: " fmt
+
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/of.h>
+#include <linux/mfd/syscon.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include <dt-bindings/interrupt-controller/arm-gic.h>
+
+#define MAXIRQ 12
+#define LS1021A_SCFGREVCR 0x200
+
+struct ls_extirq_data {
+ struct regmap *syscon;
+ u32 intpcr;
+ bool bit_reverse;
+ u32 nirq;
+ struct irq_fwspec map[MAXIRQ];
+};
+
+static int
+ls_extirq_set_type(struct irq_data *data, unsigned int type)
+{
+ struct ls_extirq_data *priv = data->chip_data;
+ irq_hw_number_t hwirq = data->hwirq;
+ u32 value, mask;
+
+ if (priv->bit_reverse)
+ mask = 1U << (31 - hwirq);
+ else
+ mask = 1U << hwirq;
+
+ switch (type) {
+ case IRQ_TYPE_LEVEL_LOW:
+ type = IRQ_TYPE_LEVEL_HIGH;
+ value = mask;
+ break;
+ case IRQ_TYPE_EDGE_FALLING:
+ type = IRQ_TYPE_EDGE_RISING;
+ value = mask;
+ break;
+ case IRQ_TYPE_LEVEL_HIGH:
+ case IRQ_TYPE_EDGE_RISING:
+ value = 0;
+ break;
+ default:
+ return -EINVAL;
+ }
+ regmap_update_bits(priv->syscon, priv->intpcr, mask, value);
+
+ return irq_chip_set_type_parent(data, type);
+}
+
+static struct irq_chip ls_extirq_chip = {
+ .name = "ls-extirq",
+ .irq_mask = irq_chip_mask_parent,
+ .irq_unmask = irq_chip_unmask_parent,
+ .irq_eoi = irq_chip_eoi_parent,
+ .irq_set_type = ls_extirq_set_type,
+ .irq_retrigger = irq_chip_retrigger_hierarchy,
+ .irq_set_affinity = irq_chip_set_affinity_parent,
+ .flags = IRQCHIP_SET_TYPE_MASKED,
+};
+
+static int
+ls_extirq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *arg)
+{
+ struct ls_extirq_data *priv = domain->host_data;
+ struct irq_fwspec *fwspec = arg;
+ irq_hw_number_t hwirq;
+
+ if (fwspec->param_count != 2)
+ return -EINVAL;
+
+ hwirq = fwspec->param[0];
+ if (hwirq >= priv->nirq)
+ return -EINVAL;
+
+ irq_domain_set_hwirq_and_chip(domain, virq, hwirq, &ls_extirq_chip,
+ priv);
+
+ return irq_domain_alloc_irqs_parent(domain, virq, 1, &priv->map[hwirq]);
+}
+
+static const struct irq_domain_ops extirq_domain_ops = {
+ .xlate = irq_domain_xlate_twocell,
+ .alloc = ls_extirq_domain_alloc,
+ .free = irq_domain_free_irqs_common,
+};
+
+static int
+ls_extirq_parse_map(struct ls_extirq_data *priv, struct device_node *node)
+{
+ const __be32 *map;
+ u32 mapsize;
+ int ret;
+
+ map = of_get_property(node, "interrupt-map", &mapsize);
+ if (!map)
+ return -ENOENT;
+ if (mapsize % sizeof(*map))
+ return -EINVAL;
+ mapsize /= sizeof(*map);
+
+ while (mapsize) {
+ struct device_node *ipar;
+ u32 hwirq, intsize, j;
+
+ if (mapsize < 3)
+ return -EINVAL;
+ hwirq = be32_to_cpup(map);
+ if (hwirq >= MAXIRQ)
+ return -EINVAL;
+ priv->nirq = max(priv->nirq, hwirq + 1);
+
+ ipar = of_find_node_by_phandle(be32_to_cpup(map + 2));
+ map += 3;
+ mapsize -= 3;
+ if (!ipar)
+ return -EINVAL;
+ priv->map[hwirq].fwnode = &ipar->fwnode;
+ ret = of_property_read_u32(ipar, "#interrupt-cells", &intsize);
+ if (ret)
+ return ret;
+
+ if (intsize > mapsize)
+ return -EINVAL;
+
+ priv->map[hwirq].param_count = intsize;
+ for (j = 0; j < intsize; ++j)
+ priv->map[hwirq].param[j] = be32_to_cpup(map++);
+ mapsize -= intsize;
+ }
+ return 0;
+}
+
+static int __init
+ls_extirq_of_init(struct device_node *node, struct device_node *parent)
+{
+
+ struct irq_domain *domain, *parent_domain;
+ struct ls_extirq_data *priv;
+ int ret;
+
+ parent_domain = irq_find_host(parent);
+ if (!parent_domain) {
+ pr_err("Cannot find parent domain\n");
+ return -ENODEV;
+ }
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->syscon = syscon_node_to_regmap(node->parent);
+ if (IS_ERR(priv->syscon)) {
+ ret = PTR_ERR(priv->syscon);
+ pr_err("Failed to lookup parent regmap\n");
+ goto out;
+ }
+ ret = of_property_read_u32(node, "reg", &priv->intpcr);
+ if (ret) {
+ pr_err("Missing INTPCR offset value\n");
+ goto out;
+ }
+
+ ret = ls_extirq_parse_map(priv, node);
+ if (ret)
+ goto out;
+
+ if (of_device_is_compatible(node, "fsl,ls1021a-extirq")) {
+ u32 revcr;
+
+ ret = regmap_read(priv->syscon, LS1021A_SCFGREVCR, &revcr);
+ if (ret)
+ goto out;
+ priv->bit_reverse = (revcr != 0);
+ }
+
+ domain = irq_domain_add_hierarchy(parent_domain, 0, priv->nirq, node,
+ &extirq_domain_ops, priv);
+ if (!domain)
+ ret = -ENOMEM;
+
+out:
+ if (ret)
+ kfree(priv);
+ return ret;
+}
+
+IRQCHIP_DECLARE(ls1021a_extirq, "fsl,ls1021a-extirq", ls_extirq_of_init);
--
2.23.0
