Hi Mark,
On Thursday 14 November 2013 07:42 PM, Mark Rutland wrote:
> On Thu, Nov 14, 2013 at 12:18:48PM +0000, Sricharan R wrote:
>> Some socs have a large number of interrupts requests to service
>> the needs of its many peripherals and subsystems. All of the
>> interrupt lines from the subsystems are not needed at the same
>> time, so they have to be muxed to the irq-controller appropriately.
>> In such places a interrupt controllers are preceded by an CROSSBAR
>> that provides flexibility in muxing the device requests to the controller
>> inputs.
>>
>> This driver takes care a allocating a free irq and then configuring the
>> crossbar IP as a part of the mpu's irqchip callbacks. crossbar_init should
>> be called right before the irqchip_init, so that it is setup to handle the
>> irqchip callbacks.
>>
>> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
>> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
>> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
>> Cc: Tony Lindgren <tony@xxxxxxxxxxx>
>> Cc: Rajendra Nayak <rnayak@xxxxxx>
>> Cc: Marc Zyngier <marc.zyngier@xxxxxxx>
>> Cc: Grant Likely <grant.likely@xxxxxxxxxx>
>> Cc: Rob Herring <rob.herring@xxxxxxxxxxx>
>> Signed-off-by: Sricharan R <r.sricharan@xxxxxx>
>> Acked-by: Kumar Gala <galak@xxxxxxxxxxxxxx> (for DT binding portion)
>> Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
>> ---
>> [V2] Addressed Thomas Gleixner <tglx@xxxxxxxxxxxxx> comments
>> and renamed the bindings as per Kumar Gala <galak@xxxxxxxxxxxxxx>
>> comments.
>> [V3] Changed static inline const to static inline int and removed
>> unnecessary variable initialization as per
>> Thomas Gleixner <tglx@xxxxxxxxxxxxx>. Updated commit tags
>> [V4] Renamed crossbar_init as irqcrossbar_init as per
>> Rajendra Nayak <rnayak@xxxxxx> suggestion.
>>
>> .../devicetree/bindings/arm/omap/crossbar.txt | 27 +++
>> drivers/irqchip/Kconfig | 8 +
>> drivers/irqchip/Makefile | 1 +
>> drivers/irqchip/irq-crossbar.c | 206 ++++++++++++++++++++
>> include/linux/irqchip/irq-crossbar.h | 11 ++
>> 5 files changed, 253 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> create mode 100644 drivers/irqchip/irq-crossbar.c
>> create mode 100644 include/linux/irqchip/irq-crossbar.h
>>
>> diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> new file mode 100644
>> index 0000000..fb88585
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
>> @@ -0,0 +1,27 @@
>> +Some socs have a large number of interrupts requests to service
>> +the needs of its many peripherals and subsystems. All of the
>> +interrupt lines from the subsystems are not needed at the same
>> +time, so they have to be muxed to the irq-controller appropriately.
>> +In such places a interrupt controllers are preceded by an CROSSBAR
>> +that provides flexibility in muxing the device requests to the controller
>> +inputs.
>> +
>> +Required properties:
>> +- compatible : Should be "ti,irq-crossbar"
>> +- reg: Base address and the size of the crossbar registers.
>> +- ti,max-irqs: Total number of irqs available at the interrupt controller.
>> +- ti,reg-size: Size of a individual register in bytes. Every individual
>> + register is assumed to be of same size. Valid sizes are 1, 2, 4.
>> +- ti,irqs-reserved: List of the reserved irq lines that are not muxed using
>> + crossbar. These interrupt lines are reserved in the soc,
>> + so crossbar bar driver should not consider them as free
>> + lines.
> The combination of the ti,max-irqs and ti,irqs-reserved properties seems
> backwards to me. Why can we not describe the set of IRQs that _can_ be
> used?
Total set of irqs that are usable is max - reserved. Since reserved irqs
are not continuous, we have to give the list. During the init we count
the total number of reserved and get the usable one.
>> +
>> +Examples:
>> + crossbar_mpu: @4a020000 {
>> + compatible = "ti,irq-crossbar";
>> + reg = <0x4a002a48 0x130>;
>> + ti,max-irqs = <160>;
>> + ti,reg-size = <2>;
>> + ti,irqs-reserved = <0 1 2 3 5 6 131 132 139 140>;
>> + };
> [...]
>
>> + /* Get and mark reserved irqs */
>> + irqsr = of_get_property(node, "ti,irqs-reserved", &size);
>> + if (irqsr) {
>> + size /= sizeof(__be32);
>> +
>> + for (i = 0; i < size; i++) {
>> + entry = be32_to_cpup(irqsr + i);
>> + if (entry > max) {
>> + pr_err("Invalid reserved entry\n");
>> + goto err3;
>> + }
>> + cb->irq_map[entry] = 0;
>> + }
>> + }
> Don't deal with the raw DTB. Use of_property_read_u32_index.
Ok, i will correct this.
>> +
>> + cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL);
>> + if (!cb->register_offsets)
>> + goto err3;
>> +
>> + of_property_read_u32(node, "ti,reg-size", &size);
> If "ti,reg-size" isn't present, size is uninitialized. Please check the
> return value of of_property_read_u32.
Ok, will correct this.
Regards,
Sricharan
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