Hi Mark, On Friday 20 September 2013 02:28 PM, Mark Rutland wrote: > Hi, > > I have a few comments, mostly on the DT binding and parsing. > Thanks for the review. The idea of seeing the crossbar as a new IRQCHIP itself did not go and the latest direction on this was to handle it inside the GIC. http://www.spinics.net/lists/linux-omap/msg97085.html I am working on that now. I would have agreed with most of the comments below, otherwise. >> diff --git a/Documentation/devicetree/bindings/arm/omap/irq-crossbar.txt b/Documentation/devicetree/bindings/arm/omap/irq-crossbar.txt >> new file mode 100644 >> index 0000000..5d465cf >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/arm/omap/irq-crossbar.txt >> @@ -0,0 +1,39 @@ >> +* IRQ CROSSBAR >> + >> +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 "irq-crossbar" > Missing vendor prefix, this should be something like "ti,irq-crossbar". > Does this have a more specific name than CROSSBAR that can be used to > qualify it? yes, ti,irq-crossbar. Not sure if it can be called as anything generically apart from crossbar . >> +- interrupt-parent: phandle to crossbar's interrupt parent. >> +- interrupt-controller: Identifies the node as an interrupt controller. >> +- interrupt-cells: Should be the same value as the interrupt parent. > That doesn't make sense. The crossbar driver is necessarily interpreting > these cells in a way the parent won't (as it supports more interrupts). > What are the meaning of these cells? These properties were added so that the DT code identifies this as a interrupt controller and map the children's irq in to this domain and to map the free irqs allocated in this driver to its parent. >> +- reg: Base address and the size of the crossbar registers. >> +- max-crossbar-lines: Total number of input lines of the crossbar. >> +- max-irqs: Total number of irqs available at the interrupt controller. > Is this the maximum number of interrupts targeting the parent interrupt > controller? Starting at what number, ending at what number? Can this > have gaps? > > Is this a shortcut so in the GIC case you don't have to describe up to > 160 interrupts? I can see why you don't want to, but there's a big loss > of generality here... > Yes, this was the maximum irqs available at the parent. The gaps was not considered here because it was mentioned used the below property irqs-reserved. >> +- reg-size: size of the crossbar registers. > As in the size of all the registers (the size component of reg)? > > Or is this the size of each individual register? Does that apply to all > registers or only a subset of them? > > What units are these in, bytes? > > What are valid sizes? > > Is this really that configurable? This was meant to describe the size a individual register and applied to all. This was used to choose the API's to write. But yes some more description could be made here. >> +- 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. > Are these reserved inputs lines, or outputs to the parent interrupt > controller? > > What is the format of each entry in this list? > > The example seems to be a different format to the parent interrupt > controller (which per your binding also defined the crossbar's interrupt > format). While <0 1 2> is a valid interrupt per the GIC binding (SPI 0 > edge-triggered both ways), <3 5 6>, <131 132 139>, and <140 . .> are > not. These were parent's input lines that were not muxed from crossbar but directly connected from peripherals, so the driver should not consider it as a free line while allocating a irq. This property was meant to interpreted only in this driver. >> + >> +Examples: >> + crossbar_mpu: @4a020000 { >> + compatible = "irq-crossbar"; >> + interrupt-parent = <&gic>; >> + interrupt-controller; >> + #interrupt-cells = <3>; >> + reg = <0x4a002a48 0x130>; >> + max-crossbar-lines = <512>; >> + max-irqs = <160>; >> + reg-size = <2>; >> + irqs-reserved = <0 1 2 3 5 6 131 132 139 140>; >> + #address-cells = <1>; >> + #size-cells = <1>; > Why are there #address-cells and #size cells? This has no children, and > this affects any interrupt-map property (as the parent unit address now > must be a single cell, that isn't going to be used). > > [...] yes, they could have been dropped and simply inherit from parent. >> +static int crossbar_set_affinity(struct irq_data *d, >> + const struct cpumask *mask_val, >> + bool force) >> +{ >> + struct irq_chip *chip; >> + struct irq_data *data; >> + int ret = 0; >> + >> + crossbar_to_irq_chip_data(d->hwirq, &chip, &data); >> + >> + if (chip->irq_set_affinity) >> + ret = chip->irq_set_affinity(data, mask_val, force); >> + >> + return ret; > So if our parent chip can't set affinity, we pretend it can? > > irq_set_affinity in kernel/irq/manage.c returns -EINVAL if an irqchip > doesn't have irq_set_affinity. > Yes the return value should be corrected for the other case. >> +/* >> + * Request and free are already called in atomic contexts >> + */ >> +unsigned int crossbar_request_irq(struct irq_data *d) >> +{ >> + int cb_no = d->hwirq; >> + int virq = allocate_free_irq(cb_no); >> + void *irq = &cb->crossbar_map[cb_no].hwirq; >> + int err; >> + >> + err = request_threaded_irq(virq, crossbar_irq, NULL, >> + 0, "CROSSBAR", irq); >> + if (err) >> + pr_err("\n request_irq failed for crossbar %d", cb_no); > Why does the print begin with a newline rather than ending with one? > yes, should be in the end. >> + >> + return 0; >> +} > [...] > >> +static int crossbar_domain_xlate(struct irq_domain *d, >> + struct device_node *controller, >> + const u32 *intspec, unsigned int intsize, >> + unsigned long *out_hwirq, >> + unsigned int *out_type) >> +{ >> + int i, cb_no; >> + u32 *cb_intspec = kzalloc(intsize * sizeof(int), GFP_KERNEL); >> + >> + if (!cb_intspec) >> + return -ENOMEM; >> + >> + cb_no = intspec[1]; > So #interrupt-cells must be at least <2>. You should sanity check > intsize >= 2 before this line or you'll perform an illegal array access. > yes, that was missing. >> + >> + if (WARN_ON(intsize < 1)) >> + return -EINVAL; > This sanity check is both wrong and too late, as mentioned above. > >> + >> + cb->crossbar_map[cb_no].intspec = cb_intspec; >> + >> + /* >> + * Free irq is allocated and mapped during request_irq >> + * So just save the interrupt properties here >> + */ >> + for (i = 0; i < intsize; i++) >> + cb->crossbar_map[cb_no].intspec[i] = intspec[i]; >> + >> + cb->crossbar_map[cb_no].intspec_size = intsize; >> + *out_hwirq = intspec[1]; >> + *out_type = IRQ_TYPE_NONE; >> + >> + return 0; >> +} >> + >> +const struct irq_domain_ops crossbar_domain_ops = { >> + .map = crossbar_domain_map, >> + .xlate = crossbar_domain_xlate >> +}; >> + >> +static int __init crossbar_of_init(struct device_node *node, >> + struct device_node *parent) >> +{ >> + int i, size, max, reserved = 0; >> + const __be32 *irqsr; >> + >> + if (!parent) { >> + pr_err("\n interrupt-parent is missing"); > Another odd newline. correct. >> + return -ENODEV; >> + } >> + >> + cb = kzalloc(sizeof(struct cb_device *), GFP_KERNEL); >> + >> + if (!cb) >> + return -ENOMEM; >> + >> + cb->irqp = parent; >> + >> + cb->crossbar_base = of_iomap(node, 0); >> + if (!cb->crossbar_base) >> + return -ENOMEM; > Leaking allocated cb here. Agree here and other leaks mentioned below, free is missing. >> + >> + of_property_read_u32(node, "max-crossbar-lines", &max); >> + cb->crossbar_map = kzalloc(max * sizeof(struct pirqs *), GFP_KERNEL); >> + >> + if (!cb->crossbar_map) >> + return -ENOMEM; > Leaking cb and cb->crossbar_base mapping. > >> + >> + cb->domain = irq_domain_add_linear(node, max, >> + &crossbar_domain_ops, NULL); >> + >> + if (!cb->domain) { >> + pr_err("Couldn't register an IRQ domain\n"); >> + return -ENODEV; >> + } > Leaking cb, cb->crossbar_base, and cb->crossbar_map here. > >> + >> + of_property_read_u32(node, "max-irqs", &max); >> + cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL); >> + if (!cb->irq_map) >> + return -ENOMEM; > Leaking cb, cb->crossbar_base, cb->crossbar_map, and cb->domain. > >> + >> + cb->int_max = max; >> + >> + for (i = 0; i < max; i++) >> + cb->irq_map[i] = IRQ_FREE; >> + >> + /* Get and mark reserved irqs */ >> + irqsr = of_get_property(node, "irqs-reserved", &size); >> + size /= sizeof(int); > The entries will be __be32, not int. > >> + >> + for (i = 0; i < size; i++) >> + cb->irq_map[be32_to_cpup(irqsr + i)] = 0; > No sanity check on array bounds? > > What about a dt that has something like: > > irqs-reserved = <0x0 0xcccccccc 0xffffffff>; > > It's clearly wrong, and we can detect that rather than bringing down the > kernel... yes, sanity check was required here. >> + >> + cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL); >> + if (!cb->register_offsets) >> + return -ENOMEM; > Leaking cb, cb->crossbar_base, cb->crossbar_map, cb->domain, and > cb->irq_map here. > >> + >> + of_property_read_u32(node, "reg-size", &size); > Sanity check? > >> + >> + /* >> + * Register offsets are not linear because of the >> + * reserved irqs. so find and store the offsets once. >> + */ >> + for (i = 0; i < max; i++) { >> + if (!cb->irq_map[i]) >> + continue; >> + >> + cb->register_offsets[i] = reserved; >> + reserved += size; >> + } >> + >> + switch (size) { >> + case 1: >> + cb->write = crossbar_writeb; >> + break; >> + case 2: >> + cb->write = crossbar_writew; >> + break; >> + case 4: >> + cb->write = crossbar_writel; >> + break; >> + default: >> + break; > Perform cleanup and return -EINVAL here? correct. >> + } >> + >> + return 0; >> +} >> +IRQCHIP_DECLARE(crossbar, "crossbar-irqchip", crossbar_of_init); >> -- >> 1.7.9.5 Regards, Sricharan -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
