Re: [PATCH v4 1/3] irqchip: xilinx: Add support for multiple instances

From: Marc Zyngier
Date: Mon Mar 16 2020 - 10:34:07 EST

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In reply to: Mubin Usman Sayyed: "[PATCH v4 1/3] irqchip: xilinx: Add support for multiple instances"
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On 2020-03-16 13:54, Mubin Usman Sayyed wrote:

From: Mubin Sayyed <mubin.usman.sayyed@xxxxxxxxxx>

Added support for cascaded interrupt controllers.

Following cascaded configurations have been tested,

- peripheral->xilinx-intc->xilinx-intc->gic->Cortexa53 processor
on zcu102 board
- peripheral->xilinx-intc->xilinx-intc->microblaze processor
on kcu105 board

Signed-off-by: Mubin Sayyed <mubin.usman.sayyed@xxxxxxxxxx>
Signed-off-by: Anirudha Sarangi <anirudha.sarangi@xxxxxxxxxx>
---
Changes for v4:
- Fixed review comments from Thomas - updated commit
message, variable declarations changed to reverse
fir tree and cleaned up some code.

Changes for v3:
- Modified prototype of xintc_write/xintc_read
- Fixed review comments regarding indentation/variable
names, used BIT
- Modified xintc_get_irq_local to return 0
in case of failure/no pending interrupts
- Fixed return type of xintc_read
- Reverted changes related to device name and
kept intc_dev as static

Changes for v2:
- Removed write_fn/read_fn hooks, used xintc_write/
xintc_read directly
- Moved primary_intc declaration after xintc_irq_chip
---
drivers/irqchip/irq-xilinx-intc.c | 121 ++++++++++++++++++------------
1 file changed, 71 insertions(+), 50 deletions(-)

diff --git a/drivers/irqchip/irq-xilinx-intc.c
b/drivers/irqchip/irq-xilinx-intc.c
index e3043ded8973..65b77720ef2e 100644
--- a/drivers/irqchip/irq-xilinx-intc.c
+++ b/drivers/irqchip/irq-xilinx-intc.c
@@ -38,29 +38,32 @@ struct xintc_irq_chip {
void __iomem *base;
struct irq_domain *root_domain;
u32 intr_mask;
+ struct irq_chip *intc_dev;

What is the need for this pointer? As far as I can see, all the interrupts
have the same callbacks, and even then, there should be no need to keep
a pointer to that.

+ u32 nr_irq;
};

-static struct xintc_irq_chip *xintc_irqc;
+static struct xintc_irq_chip *primary_intc;

-static void xintc_write(int reg, u32 data)
+static void xintc_write(struct xintc_irq_chip *irqc, int reg, u32 data)
{
if (static_branch_unlikely(&xintc_is_be))
- iowrite32be(data, xintc_irqc->base + reg);
+ iowrite32be(data, irqc->base + reg);
else
- iowrite32(data, xintc_irqc->base + reg);
+ iowrite32(data, irqc->base + reg);
}

-static unsigned int xintc_read(int reg)
+static u32 xintc_read(struct xintc_irq_chip *irqc, int reg)
{
if (static_branch_unlikely(&xintc_is_be))
- return ioread32be(xintc_irqc->base + reg);
+ return ioread32be(irqc->base + reg);
else
- return ioread32(xintc_irqc->base + reg);
+ return ioread32(irqc->base + reg);
}

static void intc_enable_or_unmask(struct irq_data *d)
{
- unsigned long mask = 1 << d->hwirq;
+ struct xintc_irq_chip *irqc = irq_data_get_irq_chip_data(d);
+ unsigned long mask = BIT(d->hwirq);

pr_debug("irq-xilinx: enable_or_unmask: %ld\n", d->hwirq);

@@ -69,30 +72,35 @@ static void intc_enable_or_unmask(struct irq_data *d)
* acks the irq before calling the interrupt handler
*/
if (irqd_is_level_type(d))
- xintc_write(IAR, mask);
+ xintc_write(irqc, IAR, mask);

- xintc_write(SIE, mask);
+ xintc_write(irqc, SIE, mask);
}

static void intc_disable_or_mask(struct irq_data *d)
{
+ struct xintc_irq_chip *irqc = irq_data_get_irq_chip_data(d);
+
pr_debug("irq-xilinx: disable: %ld\n", d->hwirq);
- xintc_write(CIE, 1 << d->hwirq);
+ xintc_write(irqc, CIE, BIT(d->hwirq));
}

static void intc_ack(struct irq_data *d)
{
+ struct xintc_irq_chip *irqc = irq_data_get_irq_chip_data(d);
+
pr_debug("irq-xilinx: ack: %ld\n", d->hwirq);
- xintc_write(IAR, 1 << d->hwirq);
+ xintc_write(irqc, IAR, BIT(d->hwirq));
}

static void intc_mask_ack(struct irq_data *d)
{
- unsigned long mask = 1 << d->hwirq;
+ struct xintc_irq_chip *irqc = irq_data_get_irq_chip_data(d);
+ unsigned long mask = BIT(d->hwirq);

pr_debug("irq-xilinx: disable_and_ack: %ld\n", d->hwirq);
- xintc_write(CIE, mask);
- xintc_write(IAR, mask);
+ xintc_write(irqc, CIE, mask);
+ xintc_write(irqc, IAR, mask);
}

static struct irq_chip intc_dev = {
@@ -103,13 +111,28 @@ static struct irq_chip intc_dev = {
.irq_mask_ack = intc_mask_ack,
};

+static unsigned int xintc_get_irq_local(struct xintc_irq_chip *irqc)
+{
+ unsigned int irq = 0;
+ u32 hwirq;
+
+ hwirq = xintc_read(irqc, IVR);
+ if (hwirq != -1U)
+ irq = irq_find_mapping(irqc->root_domain, hwirq);
+
+ pr_debug("irq-xilinx: hwirq=%d, irq=%d\n", hwirq, irq);
+
+ return irq;
+}
+
unsigned int xintc_get_irq(void)
{
- unsigned int hwirq, irq = -1;
+ unsigned int irq = -1;
+ u32 hwirq;

- hwirq = xintc_read(IVR);
+ hwirq = xintc_read(primary_intc, IVR);
if (hwirq != -1U)
- irq = irq_find_mapping(xintc_irqc->root_domain, hwirq);
+ irq = irq_find_mapping(primary_intc->root_domain, hwirq);

pr_debug("irq-xilinx: hwirq=%d, irq=%d\n", hwirq, irq);

@@ -118,15 +141,18 @@ unsigned int xintc_get_irq(void)

static int xintc_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hw)
{
- if (xintc_irqc->intr_mask & (1 << hw)) {
- irq_set_chip_and_handler_name(irq, &intc_dev,
- handle_edge_irq, "edge");
+ struct xintc_irq_chip *irqc = d->host_data;
+
+ if (irqc->intr_mask & BIT(hw)) {
+ irq_set_chip_and_handler_name(irq, irqc->intc_dev,
+ handle_edge_irq, "edge");
irq_clear_status_flags(irq, IRQ_LEVEL);
} else {
- irq_set_chip_and_handler_name(irq, &intc_dev,
- handle_level_irq, "level");
+ irq_set_chip_and_handler_name(irq, irqc->intc_dev,
+ handle_level_irq, "level");
irq_set_status_flags(irq, IRQ_LEVEL);
}
+ irq_set_chip_data(irq, irqc);
return 0;
}

@@ -138,12 +164,14 @@ static const struct irq_domain_ops
xintc_irq_domain_ops = {
static void xil_intc_irq_handler(struct irq_desc *desc)
{
struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct xintc_irq_chip *irqc;
u32 pending;

+ irqc = irq_data_get_irq_handler_data(&desc->irq_data);
chained_irq_enter(chip, desc);
do {
- pending = xintc_get_irq();
- if (pending == -1U)
+ pending = xintc_get_irq_local(irqc);
+ if (pending == 0U)

nit: I don't think we need to consider the sign of zero.

break;
generic_handle_irq(pending);
} while (true);
@@ -153,28 +181,19 @@ static void xil_intc_irq_handler(struct irq_desc *desc)
static int __init xilinx_intc_of_init(struct device_node *intc,
struct device_node *parent)
{
- u32 nr_irq;
- int ret, irq;
struct xintc_irq_chip *irqc;
-
- if (xintc_irqc) {
- pr_err("irq-xilinx: Multiple instances aren't supported\n");
- return -EINVAL;
- }
+ int ret, irq;

irqc = kzalloc(sizeof(*irqc), GFP_KERNEL);
if (!irqc)
return -ENOMEM;
-
- xintc_irqc = irqc;
-
irqc->base = of_iomap(intc, 0);
BUG_ON(!irqc->base);

- ret = of_property_read_u32(intc, "xlnx,num-intr-inputs", &nr_irq);
+ ret = of_property_read_u32(intc, "xlnx,num-intr-inputs", &irqc->nr_irq);
if (ret < 0) {
pr_err("irq-xilinx: unable to read xlnx,num-intr-inputs\n");
- goto err_alloc;
+ goto error;
}

ret = of_property_read_u32(intc, "xlnx,kind-of-intr", &irqc->intr_mask);
@@ -183,34 +202,35 @@ static int __init xilinx_intc_of_init(struct
device_node *intc,
irqc->intr_mask = 0;
}

- if (irqc->intr_mask >> nr_irq)
+ if (irqc->intr_mask >> irqc->nr_irq)
pr_warn("irq-xilinx: mismatch in kind-of-intr param\n");

pr_info("irq-xilinx: %pOF: num_irq=%d, edge=0x%x\n",
- intc, nr_irq, irqc->intr_mask);
+ intc, irqc->nr_irq, irqc->intr_mask);

+ irqc->intc_dev = &intc_dev;

Based on the above, this should go.

/*
* Disable all external interrupts until they are
* explicity requested.
*/
- xintc_write(IER, 0);
+ xintc_write(irqc, IER, 0);

/* Acknowledge any pending interrupts just in case. */
- xintc_write(IAR, 0xffffffff);
+ xintc_write(irqc, IAR, 0xffffffff);

/* Turn on the Master Enable. */
- xintc_write(MER, MER_HIE | MER_ME);
- if (!(xintc_read(MER) & (MER_HIE | MER_ME))) {
+ xintc_write(irqc, MER, MER_HIE | MER_ME);
+ if (xintc_read(irqc, MER) != (MER_HIE | MER_ME)) {
static_branch_enable(&xintc_is_be);
- xintc_write(MER, MER_HIE | MER_ME);
+ xintc_write(irqc, MER, MER_HIE | MER_ME);
}

- irqc->root_domain = irq_domain_add_linear(intc, nr_irq,
+ irqc->root_domain = irq_domain_add_linear(intc, irqc->nr_irq,
&xintc_irq_domain_ops, irqc);
if (!irqc->root_domain) {
pr_err("irq-xilinx: Unable to create IRQ domain\n");
- goto err_alloc;
+ goto error;
}

if (parent) {
@@ -222,16 +242,17 @@ static int __init xilinx_intc_of_init(struct
device_node *intc,
} else {
pr_err("irq-xilinx: interrupts property not in DT\n");
ret = -EINVAL;
- goto err_alloc;
+ goto error;
}
} else {
- irq_set_default_host(irqc->root_domain);
+ primary_intc = irqc;
+ irq_set_default_host(primary_intc->root_domain);

Do you still need this irq_set_default_host() horror? I thought microblaze
was fully DT-ified and didn't need this. The use of a non-legacy domain tends
to confirm this.

}

return 0;

-err_alloc:
- xintc_irqc = NULL;
+error:
+ iounmap(irqc->base);
kfree(irqc);
return ret;

Thanks,

M.
--
Jazz is not dead. It just smells funny...

Next message: Boris Ostrovsky: "Re: [PATCH 1/2] x86/xen: Make the boot CPU idle task reliable"
Previous message: Igor Opaniuk: "[PATCH v5 2/2] ARM: dts: colibri: introduce device trees with UHS-I support"
In reply to: Mubin Usman Sayyed: "[PATCH v4 1/3] irqchip: xilinx: Add support for multiple instances"
Next in thread: Mubin Usman Sayyed: "RE: [PATCH v4 1/3] irqchip: xilinx: Add support for multiple instances"
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