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Subject[PATCH v2 3/4] ARCv2: IRQ: Use build registers for getting numbers of interrupts
Date
This enhancement allows to mask all available common interrupts
in IDU interrupt controller in boot time since the kernel can
discover a number of them from the build register. Also now there
is no need to specify in device tree a list of used core interrupts
by IDU. E.g. before:

idu_intc: idu-interrupt-controller {
compatible = "snps,archs-idu-intc";
interrupt-controller;
interrupt-parent = <&core_intc>;
#interrupt-cells = <2>;
interrupts = <24 25 26 27 28 29 30 31>;
};

and after:

idu_intc: idu-interrupt-controller {
compatible = "snps,archs-idu-intc";
interrupt-controller;
interrupt-parent = <&core_intc>;
#interrupt-cells = <2>;
};

Signed-off-by: Yuriy Kolerov <yuriy.kolerov@synopsys.com>
---
arch/arc/include/asm/irq.h | 4 ++++
arch/arc/kernel/intc-arcv2.c | 9 +++++++--
arch/arc/kernel/mcip.c | 31 +++++++++++++++++++------------
include/soc/arc/mcip.h | 17 +++++++++++++++++
4 files changed, 47 insertions(+), 14 deletions(-)

diff --git a/arch/arc/include/asm/irq.h b/arch/arc/include/asm/irq.h
index d28499a..1970d78c 100644
--- a/arch/arc/include/asm/irq.h
+++ b/arch/arc/include/asm/irq.h
@@ -18,6 +18,9 @@
*/
#define NR_CPU_IRQS 240

+/* A fixed number of exceptions which occupy first interrupt lines */
+#define NR_EXCEPTIONS 16
+
/*
* ARCv2 can support 240 interrupts in the core interrupts controllers and
* 128 interrupts in IDU. Thus 512 virtual IRQs must be enough for most
@@ -28,6 +31,7 @@
/* Platform Independent IRQs */
#define IPI_IRQ 19
#define SOFTIRQ_IRQ 21
+#define FIRST_EXT_IRQ 24

#else

diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c
index 9de0665..31246cc 100644
--- a/arch/arc/kernel/intc-arcv2.c
+++ b/arch/arc/kernel/intc-arcv2.c
@@ -109,7 +109,7 @@ static int arcv2_irq_map(struct irq_domain *d, unsigned int irq,
* core intc IRQs [16, 23]:
* Statically assigned always private-per-core (Timers, WDT, IPI, PCT)
*/
- if (hw < 24) {
+ if (hw < FIRST_EXT_IRQ) {
/*
* A subsequent request_percpu_irq() fails if percpu_devid is
* not set. That in turns sets NOAUTOEN, meaning each core needs
@@ -134,11 +134,16 @@ static int __init
init_onchip_IRQ(struct device_node *intc, struct device_node *parent)
{
struct irq_domain *root_domain;
+ struct bcr_irq_arcv2 irq_bcr;
+ unsigned int nr_cpu_irqs;
+
+ READ_BCR(ARC_REG_IRQ_BCR, irq_bcr);
+ nr_cpu_irqs = irq_bcr.irqs + NR_EXCEPTIONS;

if (parent)
panic("DeviceTree incore intc not a root irq controller\n");

- root_domain = irq_domain_add_linear(intc, NR_CPU_IRQS, &arcv2_irq_ops, NULL);
+ root_domain = irq_domain_add_linear(intc, nr_cpu_irqs, &arcv2_irq_ops, NULL);
if (!root_domain)
panic("root irq domain not avail\n");

diff --git a/arch/arc/kernel/mcip.c b/arch/arc/kernel/mcip.c
index 9988b42..45d45fc 100644
--- a/arch/arc/kernel/mcip.c
+++ b/arch/arc/kernel/mcip.c
@@ -157,15 +157,20 @@ static void idu_set_mode(unsigned int cmn_irq, unsigned int lvl,
__mcip_cmd_data(CMD_IDU_SET_MODE, cmn_irq, data.word);
}

-static void idu_irq_mask(struct irq_data *data)
+static void idu_irq_mask_raw(irq_hw_number_t hwirq)
{
unsigned long flags;

raw_spin_lock_irqsave(&mcip_lock, flags);
- __mcip_cmd_data(CMD_IDU_SET_MASK, data->hwirq, 1);
+ __mcip_cmd_data(CMD_IDU_SET_MASK, hwirq, 1);
raw_spin_unlock_irqrestore(&mcip_lock, flags);
}

+static void idu_irq_mask(struct irq_data *data)
+{
+ idu_irq_mask_raw(data->hwirq);
+}
+
static void idu_irq_unmask(struct irq_data *data)
{
unsigned long flags;
@@ -231,14 +236,12 @@ static struct irq_chip idu_irq_chip = {

};

-static irq_hw_number_t idu_first_hwirq;
-
static void idu_cascade_isr(struct irq_desc *desc)
{
struct irq_domain *idu_domain = irq_desc_get_handler_data(desc);
struct irq_chip *core_chip = irq_desc_get_chip(desc);
irq_hw_number_t core_hwirq = irqd_to_hwirq(irq_desc_get_irq_data(desc));
- irq_hw_number_t idu_hwirq = core_hwirq - idu_first_hwirq;
+ irq_hw_number_t idu_hwirq = core_hwirq - FIRST_EXT_IRQ;

chained_irq_enter(core_chip, desc);
generic_handle_irq(irq_find_mapping(idu_domain, idu_hwirq));
@@ -284,33 +287,37 @@ static int __init
idu_of_init(struct device_node *intc, struct device_node *parent)
{
struct irq_domain *domain;
- /* Read IDU BCR to confirm nr_irqs */
- int nr_irqs = of_irq_count(intc);
+ int nr_irqs;
int i, virq;
struct mcip_bcr mp;
+ struct mcip_idu_bcr idu_bcr;

READ_BCR(ARC_REG_MCIP_BCR, mp);

if (!mp.idu)
panic("IDU not detected, but DeviceTree using it");

- pr_info("MCIP: IDU referenced from Devicetree %d irqs\n", nr_irqs);
+ READ_BCR(ARC_REG_MCIP_IDU_BCR, idu_bcr);
+ nr_irqs = mcip_idu_bcr_to_nr_irqs(idu_bcr);
+
+ pr_info("MCIP: IDU supports %u common irqs\n", nr_irqs);

domain = irq_domain_add_linear(intc, nr_irqs, &idu_irq_ops, NULL);

/* Parent interrupts (core-intc) are already mapped */

for (i = 0; i < nr_irqs; i++) {
+ /* Mask all common interrupts by default */
+ idu_irq_mask_raw(i);
+
/*
* Return parent uplink IRQs (towards core intc) 24,25,.....
* this step has been done before already
* however we need it to get the parent virq and set IDU handler
* as first level isr
*/
- virq = irq_of_parse_and_map(intc, i);
- if (!i)
- idu_first_hwirq = irqd_to_hwirq(irq_get_irq_data(virq));
-
+ virq = irq_create_mapping(NULL, i + FIRST_EXT_IRQ);
+ BUG_ON(!virq);
irq_set_chained_handler_and_data(virq, idu_cascade_isr, domain);
}

diff --git a/include/soc/arc/mcip.h b/include/soc/arc/mcip.h
index 6902c2a..798c01b 100644
--- a/include/soc/arc/mcip.h
+++ b/include/soc/arc/mcip.h
@@ -14,6 +14,7 @@
#include <soc/arc/aux.h>

#define ARC_REG_MCIP_BCR 0x0d0
+#define ARC_REG_MCIP_IDU_BCR 0x0D5
#define ARC_REG_MCIP_CMD 0x600
#define ARC_REG_MCIP_WDATA 0x601
#define ARC_REG_MCIP_READBACK 0x602
@@ -69,6 +70,22 @@ struct mcip_bcr {
#endif
};

+struct mcip_idu_bcr {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ unsigned int pad:21, cirqnum:3, ver:8;
+#else
+ unsigned int ver:8, cirqnum:3, pad:21;
+#endif
+};
+
+
+/*
+ * Build register for IDU contains not an actual number of supported common
+ * interrupts but an exponent of 2 which must be multiplied by 4 to
+ * get a number of supported common interrupts.
+ */
+#define mcip_idu_bcr_to_nr_irqs(bcr) (4 * (1 << (bcr).cirqnum))
+
/*
* MCIP programming model
*
--
2.7.4

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