From 82961458def596bb31c176bbe799c4e335fb92ce Mon Sep 17 00:00:00 2001
From: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
Date: Tue, 23 Feb 2021 09:32:03 +0100
Subject: [PATCH] drivers/interrupt_controller: Simplify IRTE structure for
 readability

Let's avoid l/h accessors, and directly have all bits into one
structure.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
---
 drivers/interrupt_controller/intc_intel_vtd.c | 24 ++++-----
 drivers/interrupt_controller/intc_intel_vtd.h | 52 +++++++++----------
 2 files changed, 36 insertions(+), 40 deletions(-)

diff --git a/drivers/interrupt_controller/intc_intel_vtd.c b/drivers/interrupt_controller/intc_intel_vtd.c
index 352a1c3944a..76f478de03e 100644
--- a/drivers/interrupt_controller/intc_intel_vtd.c
+++ b/drivers/interrupt_controller/intc_intel_vtd.c
@@ -83,7 +83,7 @@ static void vtd_flush_irte_from_cache(const struct device *dev,
 
 	if (!data->pwc) {
 		sys_cache_data_range(&data->irte[irte_idx],
-				     sizeof(struct vtd_irte), K_CACHE_WB);
+				     sizeof(union vtd_irte), K_CACHE_WB);
 	}
 }
 
@@ -320,24 +320,24 @@ static int vtd_ictl_remap(const struct device *dev,
 			  uint32_t flags)
 {
 	struct vtd_ictl_data *data = dev->data;
-	struct vtd_irte irte = { 0 };
+	union vtd_irte irte = { 0 };
 
-	irte.l.vector = vector;
+	irte.bits.vector = vector;
 
 	if (IS_ENABLED(CONFIG_X2APIC)) {
-		irte.l.dst_id = arch_curr_cpu()->id;
+		irte.bits.dst_id = arch_curr_cpu()->id;
 	} else {
-		irte.l.dst_id = arch_curr_cpu()->id << 8;
+		irte.bits.dst_id = arch_curr_cpu()->id << 8;
 	}
 
-	irte.l.trigger_mode = (flags & IOAPIC_TRIGGER_MASK) >> 15;
-	irte.l.delivery_mode = (flags & IOAPIC_DELIVERY_MODE_MASK) >> 8;
-	irte.l.dst_mode = 1;
-	irte.l.redirection_hint = 1;
-	irte.l.present = 1;
+	irte.bits.trigger_mode = (flags & IOAPIC_TRIGGER_MASK) >> 15;
+	irte.bits.delivery_mode = (flags & IOAPIC_DELIVERY_MODE_MASK) >> 8;
+	irte.bits.dst_mode = 1;
+	irte.bits.redirection_hint = 1;
+	irte.bits.present = 1;
 
-	data->irte[irte_idx].low = irte.low;
-	data->irte[irte_idx].high = irte.high;
+	data->irte[irte_idx].parts.low = irte.parts.low;
+	data->irte[irte_idx].parts.high = irte.parts.high;
 
 	vtd_index_iec_invalidate(dev, irte_idx);
 
diff --git a/drivers/interrupt_controller/intc_intel_vtd.h b/drivers/interrupt_controller/intc_intel_vtd.h
index eda4f60de67..4e4ab45620e 100644
--- a/drivers/interrupt_controller/intc_intel_vtd.h
+++ b/drivers/interrupt_controller/intc_intel_vtd.h
@@ -16,35 +16,31 @@
 	((0x0FEE00000U) | (int_idx << 5) | shv | VTD_INT_FORMAT)
 
 /* Interrupt Remapping Table Entry (IRTE) for Remapped Interrupts */
-struct vtd_irte {
-	union {
-		struct vtd_irte_low {
-			uint64_t present		: 1;
-			uint64_t fpd			: 1;
-			uint64_t dst_mode		: 1;
-			uint64_t redirection_hint	: 1;
-			uint64_t trigger_mode		: 1;
-			uint64_t delivery_mode		: 3;
-			uint64_t available		: 4;
-			uint64_t _reserved_0		: 3;
-			uint64_t irte_mode		: 1;
-			uint64_t vector			: 8;
-			uint64_t _reserved_1		: 8;
-			uint64_t dst_id			: 32;
-		} l;
+union vtd_irte {
+	struct irte_parts {
 		uint64_t low;
-	};
-
-	union {
-		struct vtd_irte_high {
-			uint64_t src_id			: 16;
-			uint64_t src_id_qualifier	: 2;
-			uint64_t src_validation_type	: 2;
-			uint64_t _reserved		: 44;
-		} h;
 		uint64_t high;
-	};
-} __packed;
+	} parts;
+
+	struct irte_bits {
+		uint64_t present		: 1;
+		uint64_t fpd			: 1;
+		uint64_t dst_mode		: 1;
+		uint64_t redirection_hint	: 1;
+		uint64_t trigger_mode		: 1;
+		uint64_t delivery_mode		: 3;
+		uint64_t available		: 4;
+		uint64_t _reserved_0		: 3;
+		uint64_t irte_mode		: 1;
+		uint64_t vector			: 8;
+		uint64_t _reserved_1		: 8;
+		uint64_t dst_id			: 32;
+		uint64_t src_id			: 16;
+		uint64_t src_id_qualifier	: 2;
+		uint64_t src_validation_type	: 2;
+		uint64_t _reserved		: 44;
+	} bits __packed;
+};
 
 /* The table must be 4KB aligned, which is exactly 256 entries.
  * And since we allow only 256 entries as a maximum: let's align to it.
@@ -103,7 +99,7 @@ union qi_wait_descriptor {
 #define QI_WAIT_STATUS_COMPLETE 0x1UL
 
 struct vtd_ictl_data {
-	struct vtd_irte irte[IRTE_NUM] __aligned(0x1000);
+	union vtd_irte irte[IRTE_NUM] __aligned(0x1000);
 	struct qi_descriptor qi[QI_NUM] __aligned(0x1000);
 	int irqs[IRTE_NUM];
 	int vectors[IRTE_NUM];