msi_doorbell_pages sum up the number of iommu pages of a given order
requested to map all the registered doorbells. This function will allow
to dimension the intermediate physical address (IPA) aperture requested
to map the MSI doorbells.
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
---
v10: creation
---
include/linux/msi-doorbell.h | 14 ++++++++++++
kernel/irq/msi-doorbell.c | 52 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 66 insertions(+)
diff --git a/include/linux/msi-doorbell.h b/include/linux/msi-doorbell.h
index c455e33..146bfbc 100644
--- a/include/linux/msi-doorbell.h
+++ b/include/linux/msi-doorbell.h
@@ -35,6 +35,14 @@ msi_doorbell_register_global(phys_addr_t base, size_t size,
*/
void msi_doorbell_unregister_global(struct irq_chip_msi_doorbell_info *db);
+/**
+ * msi_doorbell_pages: compute the number of iommu pages of size 1 << order
+ * requested to map all the registered doorbells
+ *
+ * @order: iommu page order
+ */
+int msi_doorbell_pages(unsigned int order);
+
#else
static inline struct irq_chip_msi_doorbell_info *
@@ -47,6 +55,12 @@ msi_doorbell_register_global(phys_addr_t base, size_t size,
static inline void
msi_doorbell_unregister_global(struct irq_chip_msi_doorbell_info *db) {}
+static inline int
+msi_doorbell_pages(unsigned int order)
+{
+ return 0;
+}
+
#endif /* CONFIG_MSI_DOORBELL */
#endif
diff --git a/kernel/irq/msi-doorbell.c b/kernel/irq/msi-doorbell.c
index 0ff541e..a5bde37 100644
--- a/kernel/irq/msi-doorbell.c
+++ b/kernel/irq/msi-doorbell.c
@@ -60,3 +60,55 @@ void msi_doorbell_unregister_global(struct irq_chip_msi_doorbell_info *dbinfo)
mutex_unlock(&irqchip_doorbell_mutex);
}
EXPORT_SYMBOL_GPL(msi_doorbell_unregister_global);
+
+static int compute_db_mapping_requirements(phys_addr_t addr, size_t size,
+ unsigned int order)
+{
+ phys_addr_t offset, granule;
+ unsigned int nb_pages;
+
+ granule = (uint64_t)(1 << order);
+ offset = addr & (granule - 1);
+ size = ALIGN(size + offset, granule);
+ nb_pages = size >> order;
+
+ return nb_pages;
+}
+
+static int
+compute_dbinfo_mapping_requirements(struct irq_chip_msi_doorbell_info *dbinfo,
+ unsigned int order)
+{
+ int ret = 0;
+
+ if (!dbinfo->doorbell_is_percpu) {
+ ret = compute_db_mapping_requirements(dbinfo->global_doorbell,
+ dbinfo->size, order);
+ } else {
+ phys_addr_t __percpu *pbase;
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ pbase = per_cpu_ptr(dbinfo->percpu_doorbells, cpu);
+ ret += compute_db_mapping_requirements(*pbase,
+ dbinfo->size,
+ order);
+ }
+ }
+ return ret;
+}
+
+int msi_doorbell_pages(unsigned int order)
+{
+ struct irqchip_doorbell *db;
+ int ret = 0;
+
+ mutex_lock(&irqchip_doorbell_mutex);
+ list_for_each_entry(db, &irqchip_doorbell_list, next) {
+ ret += compute_dbinfo_mapping_requirements(&db->info, order);
+ }
+ mutex_unlock(&irqchip_doorbell_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(msi_doorbell_pages);
--
1.9.1
--
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