linux-kernel - [patch 02/37] device: Add device::msi_data pointer and struct msi_device

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Message-ID: <20211126230524.045836616@linutronix.de>
Date:   Sat, 27 Nov 2021 02:21:20 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     Bjorn Helgaas <helgaas@...nel.org>, Marc Zygnier <maz@...nel.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Megha Dey <megha.dey@...el.com>,
        Ashok Raj <ashok.raj@...el.com>, linux-pci@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        iommu@...ts.linux-foundation.org, dmaengine@...r.kernel.org,
        Stuart Yoder <stuyoder@...il.com>,
        Laurentiu Tudor <laurentiu.tudor@....com>,
        Nishanth Menon <nm@...com>, Tero Kristo <kristo@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, x86@...nel.org,
        Vinod Koul <vkoul@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Will Deacon <will@...nel.org>, Sinan Kaya <okaya@...nel.org>
Subject: [patch 02/37] device: Add device::msi_data pointer and struct msi_device_data

Create struct msi_device_data and add a pointer of that type to struct
dev_msi_info, which is part of struct device. Provide an allocator function
which can be invoked from the MSI interrupt allocation code pathes.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 include/linux/device.h |    5 +++++
 include/linux/msi.h    |   12 +++++++++++-
 kernel/irq/msi.c       |   33 +++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)

--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -45,6 +45,7 @@ struct iommu_ops;
 struct iommu_group;
 struct dev_pin_info;
 struct dev_iommu;
+struct msi_device_data;
 
 /**
  * struct subsys_interface - interfaces to device functions
@@ -374,11 +375,15 @@ struct dev_links_info {
 /**
  * struct dev_msi_info - Device data related to MSI
  * @domain:	The MSI interrupt domain associated to the device
+ * @data:	Pointer to MSI device data
  */
 struct dev_msi_info {
 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
 	struct irq_domain	*domain;
 #endif
+#ifdef CONFIG_GENERIC_MSI_IRQ
+	struct msi_device_data	*data;
+#endif
 };
 
 /**
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -2,6 +2,7 @@
 #ifndef LINUX_MSI_H
 #define LINUX_MSI_H
 
+#include <linux/spinlock.h>
 #include <linux/list.h>
 #include <asm/msi.h>
 
@@ -170,6 +171,16 @@ struct msi_desc {
 	};
 };
 
+/**
+ * msi_device_data - MSI per device data
+ * @lock:		Spinlock to protect register access
+ */
+struct msi_device_data {
+	raw_spinlock_t		lock;
+};
+
+int msi_setup_device_data(struct device *dev);
+
 /* Helpers to hide struct msi_desc implementation details */
 #define msi_desc_to_dev(desc)		((desc)->dev)
 #define dev_to_msi_list(dev)		(&(dev)->msi_list)
@@ -185,7 +196,6 @@ struct msi_desc {
 			for (__irq = (desc)->irq;			\
 			     __irq < ((desc)->irq + (desc)->nvec_used);	\
 			     __irq++)
-
 #ifdef CONFIG_IRQ_MSI_IOMMU
 static inline const void *msi_desc_get_iommu_cookie(struct msi_desc *desc)
 {
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -73,6 +73,39 @@ void get_cached_msi_msg(unsigned int irq
 }
 EXPORT_SYMBOL_GPL(get_cached_msi_msg);
 
+static void msi_device_data_release(struct device *dev, void *res)
+{
+	WARN_ON_ONCE(!list_empty(&dev->msi_list));
+	dev->msi.data = NULL;
+}
+
+/**
+ * msi_setup_device_data - Setup MSI device data
+ * @dev:	Device for which MSI device data should be set up
+ *
+ * Return: 0 on success, appropriate error code otherwise
+ *
+ * This can be called more than once for @dev. If the MSI device data is
+ * already allocated the call succeeds. The allocated memory is
+ * automatically released when the device is destroyed.
+ */
+int msi_setup_device_data(struct device *dev)
+{
+	struct msi_device_data *md;
+
+	if (dev->msi.data)
+		return 0;
+
+	md = devres_alloc(msi_device_data_release, sizeof(*md), GFP_KERNEL);
+	if (!md)
+		return -ENOMEM;
+
+	raw_spin_lock_init(&md->lock);
+	dev->msi.data = md;
+	devres_add(dev, md);
+	return 0;
+}
+
 #ifdef CONFIG_SYSFS
 static ssize_t msi_mode_show(struct device *dev, struct device_attribute *attr,
 			     char *buf)