PCI/MSI: Move pci_disable_msi() to api.c

msi.c is a maze of randomly sorted functions which makes the code
unreadable. As a first step split the driver visible API and the internal
implementation which also allows proper API documentation via one file.

Create drivers/pci/msi/api.c to group all exported device-driver PCI/MSI
APIs in one C file.

Begin by moving pci_disable_msi() there and add kernel-doc for the function
as appropriate.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://lore.kernel.org/r/20221111122014.696798036@linutronix.de

diff --git a/drivers/pci/msi/Makefile b/drivers/pci/msi/Makefile
index 4e0a7e0..839ff72 100644 (file)
--- a/drivers/pci/msi/Makefile
+++ b/drivers/pci/msi/Makefile
@@ -2,6 +2,5 @@
 #
 # Makefile for the PCI/MSI
 obj-$(CONFIG_PCI)                      += pcidev_msi.o
-obj-$(CONFIG_PCI_MSI)                  += msi.o
-obj-$(CONFIG_PCI_MSI)                  += irqdomain.o
+obj-$(CONFIG_PCI_MSI)                  += api.o msi.o irqdomain.o
 obj-$(CONFIG_PCI_MSI_ARCH_FALLBACKS)   += legacy.o

diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
new file mode 100644 (file)
index 0000000..7485942
--- /dev/null
+++ b/drivers/pci/msi/api.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCI MSI/MSI-X — Exported APIs for device drivers
+ *
+ * Copyright (C) 2003-2004 Intel
+ * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
+ * Copyright (C) 2016 Christoph Hellwig.
+ * Copyright (C) 2022 Linutronix GmbH
+ */
+
+#include <linux/export.h>
+
+#include "msi.h"
+
+/**
+ * pci_disable_msi() - Disable MSI interrupt mode on device
+ * @dev: the PCI device to operate on
+ *
+ * Legacy device driver API to disable MSI interrupt mode on device,
+ * free earlier allocated interrupt vectors, and restore INTx emulation.
+ * The PCI device Linux IRQ (@dev->irq) is restored to its default
+ * pin-assertion IRQ. This is the cleanup pair of pci_enable_msi().
+ *
+ * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API
+ * pair should, in general, be used instead.
+ */
+void pci_disable_msi(struct pci_dev *dev)
+{
+       if (!pci_msi_enabled() || !dev || !dev->msi_enabled)
+               return;
+
+       msi_lock_descs(&dev->dev);
+       pci_msi_shutdown(dev);
+       pci_free_msi_irqs(dev);
+       msi_unlock_descs(&dev->dev);
+}
+EXPORT_SYMBOL(pci_disable_msi);

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 5c310df..4a1300b 100644 (file)
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -163,7 +163,7 @@ void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
 }
 EXPORT_SYMBOL_GPL(pci_write_msi_msg);
 
-static void free_msi_irqs(struct pci_dev *dev)
+void pci_free_msi_irqs(struct pci_dev *dev)
 {
        pci_msi_teardown_msi_irqs(dev);
 
@@ -413,7 +413,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
 
 err:
        pci_msi_unmask(entry, msi_multi_mask(entry));
-       free_msi_irqs(dev);
+       pci_free_msi_irqs(dev);
 fail:
        dev->msi_enabled = 0;
 unlock:
@@ -531,7 +531,7 @@ static int msix_setup_interrupts(struct pci_dev *dev, void __iomem *base,
        goto out_unlock;
 
 out_free:
-       free_msi_irqs(dev);
+       pci_free_msi_irqs(dev);
 out_unlock:
        msi_unlock_descs(&dev->dev);
        kfree(masks);
@@ -680,7 +680,7 @@ int pci_msi_vec_count(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pci_msi_vec_count);
 
-static void pci_msi_shutdown(struct pci_dev *dev)
+void pci_msi_shutdown(struct pci_dev *dev)
 {
        struct msi_desc *desc;
 
@@ -701,18 +701,6 @@ static void pci_msi_shutdown(struct pci_dev *dev)
        pcibios_alloc_irq(dev);
 }
 
-void pci_disable_msi(struct pci_dev *dev)
-{
-       if (!pci_msi_enable || !dev || !dev->msi_enabled)
-               return;
-
-       msi_lock_descs(&dev->dev);
-       pci_msi_shutdown(dev);
-       free_msi_irqs(dev);
-       msi_unlock_descs(&dev->dev);
-}
-EXPORT_SYMBOL(pci_disable_msi);
-
 /**
  * pci_msix_vec_count - return the number of device's MSI-X table entries
  * @dev: pointer to the pci_dev data structure of MSI-X device function
@@ -797,7 +785,7 @@ void pci_disable_msix(struct pci_dev *dev)
 
        msi_lock_descs(&dev->dev);
        pci_msix_shutdown(dev);
-       free_msi_irqs(dev);
+       pci_free_msi_irqs(dev);
        msi_unlock_descs(&dev->dev);
 }
 EXPORT_SYMBOL(pci_disable_msix);

diff --git a/drivers/pci/msi/msi.h b/drivers/pci/msi/msi.h
index d8f62d9..6348792 100644 (file)
--- a/drivers/pci/msi/msi.h
+++ b/drivers/pci/msi/msi.h
@@ -84,6 +84,10 @@ static inline __attribute_const__ u32 msi_multi_mask(struct msi_desc *desc)
        return (1 << (1 << desc->pci.msi_attrib.multi_cap)) - 1;
 }
 
+/* MSI internal functions invoked from the public APIs */
+void pci_msi_shutdown(struct pci_dev *dev);
+void pci_free_msi_irqs(struct pci_dev *dev);
+
 /* Legacy (!IRQDOMAIN) fallbacks */
 #ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS
 int pci_msi_legacy_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);