[PATCH v3 11/35] genirq/msi: Allow shadow declarations of msi_msg::$member

David Woodhouse
2020-10-24T21:36:24Z

From: Thomas Gleixner <tglx@linutronix.de>

Architectures like x86 have their MSI messages in various bits of the data,
address_lo and address_hi field. Composing or decomposing these messages
with bitmasks and shifts is possible, but unreadable gunk.

Allow architectures to provide an architecture specific representation for
each member of msi_msg. Provide empty defaults for each and stick them into
an union.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
include/asm-generic/msi.h | 4 ++++
include/linux/msi.h | 46 +++++++++++++++++++++++++++++++++++----
2 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/include/asm-generic/msi.h b/include/asm-generic/msi.h
index e6795f088bdd..25344de0e8f9 100644
--- a/include/asm-generic/msi.h
+++ b/include/asm-generic/msi.h
@@ -4,6 +4,8 @@

#include <linux/types.h>

+#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
+
#ifndef NUM_MSI_ALLOC_SCRATCHPAD_REGS
# define NUM_MSI_ALLOC_SCRATCHPAD_REGS 2
#endif
@@ -30,4 +32,6 @@ typedef struct msi_alloc_info {

#define GENERIC_MSI_DOMAIN_OPS 1

+#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
+
#endif
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 6b584cc4757c..360a0a7e7341 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -4,11 +4,50 @@

#include <linux/kobject.h>
#include <linux/list.h>
+#include <asm/msi.h>
+
+/* Dummy shadow structures if an architecture does not define them */
+#ifndef arch_msi_msg_addr_lo
+typedef struct arch_msi_msg_addr_lo {
+ u32 address_lo;
+} __attribute__ ((packed)) arch_msi_msg_addr_lo_t;
+#endif
+
+#ifndef arch_msi_msg_addr_hi
+typedef struct arch_msi_msg_addr_hi {
+ u32 address_hi;
+} __attribute__ ((packed)) arch_msi_msg_addr_hi_t;
+#endif
+
+#ifndef arch_msi_msg_data
+typedef struct arch_msi_msg_data {
+ u32 data;
+} __attribute__ ((packed)) arch_msi_msg_data_t;
+#endif

+/**
+ * msi_msg - Representation of a MSI message
+ * @address_lo: Low 32 bits of msi message address
+ * @arch_addrlo: Architecture specific shadow of @address_lo
+ * @address_hi: High 32 bits of msi message address
+ * (only used when device supports it)
+ * @arch_addrhi: Architecture specific shadow of @address_hi
+ * @data: MSI message data (usually 16 bits)
+ * @arch_data: Architecture specific shadow of @data
+ */
struct msi_msg {
- u32 address_lo; /* low 32 bits of msi message address */
- u32 address_hi; /* high 32 bits of msi message address */
- u32 data; /* 16 bits of msi message data */
+ union {
+ u32 address_lo;
+ arch_msi_msg_addr_lo_t arch_addr_lo;
+ };
+ union {
+ u32 address_hi;
+ arch_msi_msg_addr_hi_t arch_addr_hi;
+ };
+ union {
+ u32 data;
+ arch_msi_msg_data_t arch_data;
+ };
};

extern int pci_msi_ignore_mask;
@@ -243,7 +282,6 @@ struct msi_controller {
#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN

#include <linux/irqhandler.h>
-#include <asm/msi.h>

struct irq_domain;
struct irq_domain_ops;