[PATCH v2 04/19] genirq: Add new struct ipi_mask and helper functions

[Qais Yousef]

cpumask is limited to NR_CPUS. Introduce ipi_mask which allows us to address
cpu range that is higher than NR_CPUS which is required for drivers to send
IPIs for coprocessor that are outside Linux CPU range.

Signed-off-by: Qais Yousef <qais.yousef@xxxxxxxxxx>
---
 include/linux/irq.h | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index 3c1c96786248..7d8c3d88f16f 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -19,6 +19,7 @@
 #include <linux/irqreturn.h>
 #include <linux/irqnr.h>
 #include <linux/errno.h>
+#include <linux/slab.h>
 #include <linux/topology.h>
 #include <linux/wait.h>
 #include <linux/io.h>
@@ -128,6 +129,29 @@ struct msi_desc;
 struct irq_domain;
 
 /**
+ * struct ipi_mask - IPI mask information
+ * @nbits: number of bits in cpumask
+ * @offset: the starting position at which the first cpu is set in the mask
+ *	    this is only required by generic code to manage per_cpu IPIs.
+ * @global: whether the mask is SMP IPI ie: subset of cpu_possible_mask or not
+ * @cpumask: cpumask to be used when the ipi_mask is global
+ * @cpu_bitmap: the cpu bitmap to use when the ipi_mask is not global
+ *
+ * ipi_mask is similar to cpumask, but it provides nbits that's configurable
+ * rather than fixed to NR_CPUS. We need that to describe IPI masks to
+ * coprocessors that are outside the NR_CPUS range.
+ */
+struct ipi_mask {
+	unsigned int	nbits;
+	unsigned int	offset;
+	bool		global;
+	union {
+		struct cpumask	cpumask;
+		unsigned long	cpu_bitmap[0];
+	};
+};
+
+/**
  * struct irq_common_data - per irq data shared by all irqchips
  * @state_use_accessors: status information for irq chip functions.
  *			Use accessor functions to deal with it
@@ -934,4 +958,64 @@ static inline u32 irq_reg_readl(struct irq_chip_generic *gc,
 		return readl(gc->reg_base + reg_offset);
 }
 
+static inline const unsigned long *ipi_mask_bits(const struct ipi_mask *ipimask)
+{
+	if (ipimask->global)
+		return cpumask_bits(&ipimask->cpumask);
+	else
+		return ipimask->cpu_bitmap;
+}
+
+static inline unsigned int ipi_mask_weight(const struct ipi_mask *ipimask)
+{
+	if (ipimask->global)
+		return cpumask_weight(&ipimask->cpumask);
+	else
+		return bitmap_weight(ipimask->cpu_bitmap, ipimask->nbits);
+}
+
+static inline void ipi_mask_copy(struct ipi_mask *dst,
+				 const struct ipi_mask *src)
+{
+	dst->nbits = src->nbits;
+	dst->global = src->global;
+
+	if (src->global)
+		return cpumask_copy(&dst->cpumask, &src->cpumask);
+	else
+		return bitmap_copy(dst->cpu_bitmap,
+					src->cpu_bitmap, src->nbits);
+}
+
+static inline struct ipi_mask *ipi_mask_alloc(unsigned int nbits)
+{
+	size_t size = sizeof(struct ipi_mask) + BITS_TO_LONGS(nbits);
+	return kzalloc(size, GFP_KERNEL);
+}
+
+static inline void ipi_mask_free(struct ipi_mask *ipimask)
+{
+	kfree(ipimask);
+}
+
+static inline void ipi_mask_set_cpumask(struct ipi_mask *ipimask,
+					const struct cpumask *cpumask)
+{
+	ipimask->nbits = nr_cpu_ids;
+	ipimask->global = true;
+	cpumask_copy(&ipimask->cpumask, cpumask);
+}
+
+static inline void ipi_mask_set_offset(struct ipi_mask *ipimask,
+				       unsigned int offset)
+{
+	ipimask->offset = offset;
+}
+
+#define ipi_mask_for_each_cpu(cpu, mask)			\
+	for ((cpu) = -1;					\
+		(cpu) = find_next_bit(ipi_mask_bits(mask),	\
+				      (mask)->nbits, (cpu)+1),	\
+		(cpu) < (mask)->nbits;)
+
 #endif /* _LINUX_IRQ_H */
-- 
2.1.0

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