To re-use the code that initialises the GIC (found in
__gic_init_bases()), from within a platform driver, it is necessary to
move the code from the __init section so that it is always present and
not removed. Unfortunately, it is not possible to simply drop the __init
from the function declaration for __gic_init_bases() because it contains
calls to set_smp_cross_call() and set_handle_irq() which are both
located in the __init section. Fortunately, these calls are only
required for the root controller and because the initial platform driver
will only support non-root controllers that can be initialised later in
the boot process, we can move these calls to another function.

Move the bulk of the code from __gic_init_bases() to a new function
called gic_init_bases() which is not located in the __init section and
can be used by the platform driver. Update __gic_init_bases() to call
gic_init_bases() and if necessary, set_smp_cross_call() and
set_handle_irq().

To allow the platform driver to dynamically allocate the GIC chip data
structure, rather than passing an index to reference the GIC to
gic_init_bases() pass a pointer to the chip data instead. This means
that the name must be passed to gic_init_bases() as well, because the
name will not be passed upon an index for a platform device.

Signed-off-by: Jon Hunter <jonath...@nvidia.com>
---
 drivers/irqchip/irq-gic.c | 71 +++++++++++++++++++++++++++++++----------------
 1 file changed, 47 insertions(+), 24 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index 2fc5018d6eb9..15e8a12813cc 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -1002,32 +1002,29 @@ static const struct irq_domain_ops gic_irq_domain_ops = 
{
        .unmap = gic_irq_domain_unmap,
 };
 
-static int __init __gic_init_bases(unsigned int gic_nr, int irq_start,
-                          void __iomem *dist_base, void __iomem *cpu_base,
-                          u32 percpu_offset, struct fwnode_handle *handle)
+static int gic_init_bases(struct gic_chip_data *gic, int irq_start,
+                         void __iomem *dist_base, void __iomem *cpu_base,
+                         u32 percpu_offset, struct fwnode_handle *handle,
+                         const char *name)
 {
        irq_hw_number_t hwirq_base;
-       struct gic_chip_data *gic;
-       int gic_irqs, irq_base, i, ret;
-
-       BUG_ON(gic_nr >= CONFIG_ARM_GIC_MAX_NR);
+       int gic_irqs, irq_base, ret;
 
-       gic = &gic_data[gic_nr];
+       if (WARN_ON(!gic || gic->domain))
+               return -EINVAL;
 
        /* Initialize irq_chip */
        gic->chip = gic_chip;
+       gic->chip.name = name;
 
-       if (static_key_true(&supports_deactivate) && gic_nr == 0) {
+       if (static_key_true(&supports_deactivate) && gic == &gic_data[0]) {
                gic->chip.irq_mask = gic_eoimode1_mask_irq;
                gic->chip.irq_eoi = gic_eoimode1_eoi_irq;
                gic->chip.irq_set_vcpu_affinity = gic_irq_set_vcpu_affinity;
-               gic->chip.name = kasprintf(GFP_KERNEL, "GICv2");
-       } else {
-               gic->chip.name = kasprintf(GFP_KERNEL, "GIC-%d", gic_nr);
        }
 
 #ifdef CONFIG_SMP
-       if (gic_nr == 0)
+       if (gic == &gic_data[0])
                gic->chip.irq_set_affinity = gic_set_affinity;
 #endif
 
@@ -1081,7 +1078,7 @@ static int __init __gic_init_bases(unsigned int gic_nr, 
int irq_start,
                 * For primary GICs, skip over SGIs.
                 * For secondary GICs, skip over PPIs, too.
                 */
-               if (gic_nr == 0 && (irq_start & 31) > 0) {
+               if (gic == &gic_data[0] && (irq_start & 31) > 0) {
                        hwirq_base = 16;
                        if (irq_start != -1)
                                irq_start = (irq_start & ~31) + 16;
@@ -1108,6 +1105,42 @@ static int __init __gic_init_bases(unsigned int gic_nr, 
int irq_start,
                goto error;
        }
 
+       return 0;
+
+error:
+       if (IS_ENABLED(CONFIG_GIC_NON_BANKED) && percpu_offset) {
+               free_percpu(gic->dist_base.percpu_base);
+               free_percpu(gic->cpu_base.percpu_base);
+       }
+
+       return ret;
+}
+
+static int __init __gic_init_bases(unsigned int gic_nr, int irq_start,
+                          void __iomem *dist_base, void __iomem *cpu_base,
+                          u32 percpu_offset, struct fwnode_handle *handle)
+{
+       struct gic_chip_data *gic;
+       char *name;
+       int i, ret;
+
+       if (WARN_ON(gic_nr >= CONFIG_ARM_GIC_MAX_NR))
+               return -EINVAL;
+
+       gic = &gic_data[gic_nr];
+
+       if (static_key_true(&supports_deactivate) && gic_nr == 0)
+               name = kasprintf(GFP_KERNEL, "GICv2");
+       else
+               name = kasprintf(GFP_KERNEL, "GIC-%d", gic_nr);
+
+       ret = gic_init_bases(gic, irq_start, dist_base, cpu_base, percpu_offset,
+                            handle, name);
+       if (ret) {
+               kfree(name);
+               return ret;
+       }
+
        if (gic_nr == 0) {
                /*
                 * Initialize the CPU interface map to all CPUs.
@@ -1130,16 +1163,6 @@ static int __init __gic_init_bases(unsigned int gic_nr, 
int irq_start,
        gic_pm_init(gic);
 
        return 0;
-
-error:
-       if (IS_ENABLED(CONFIG_GIC_NON_BANKED) && percpu_offset) {
-               free_percpu(gic->dist_base.percpu_base);
-               free_percpu(gic->cpu_base.percpu_base);
-       }
-
-       kfree(gic->chip.name);
-
-       return ret;
 }
 
 void __init gic_init(unsigned int gic_nr, int irq_start,
-- 
2.1.4

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