linux-kernel - Re: [RFC/PATCH 1/4] pci: Add pci_enable_device

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Date:	Tue, 18 Dec 2007 11:02:37 +1100
From:	Benjamin Herrenschmidt <benh@...nel.crashing.org>
To:	Johannes Weiner <hannes@...urebad.de>
Cc:	linux-pci@...ey.karlin.mff.cuni.cz, Alan Cox <alan@...hat.com>,
	Greg Kroah-Hartman <greg@...ah.com>, jgarzik@...ox.com,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	wingel@...o-system.com,
	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>,
	james.smart@...lex.com, linux-driver@...gic.com,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC/PATCH 1/4] pci: Add pci_enable_device_{io,mem} intefaces


On Tue, 2007-12-18 at 00:49 +0100, Johannes Weiner wrote:

> These two functions should be refactored, the only difference is the
> flag checking.

FYI. Here's what it looks like in my next version of the patch:

Index: linux-work/drivers/pci/pci.c
===================================================================
--- linux-work.orig/drivers/pci/pci.c	2007-10-15 11:19:38.000000000 +1000
+++ linux-work/drivers/pci/pci.c	2007-12-18 11:01:20.000000000 +1100
@@ -736,6 +736,51 @@ pci_enable_device_bars(struct pci_dev *d
 	return err;
 }
 
+static int __pci_enable_device_flags(struct pci_dev *dev,
+				     resource_size_t flags)
+{
+	int err;
+	int i, bars = 0;
+
+	if (atomic_add_return(1, &dev->enable_cnt) > 1)
+		return 0;		/* already enabled */
+
+	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
+		if (dev->resource[i].flags & flags)
+			bars |= (1 << i);
+
+	err = do_pci_enable_device(dev, bars);
+	if (err < 0)
+		atomic_dec(&dev->enable_cnt);
+	return err;
+}
+
+/**
+ * pci_enable_device_io - Initialize a device for use with IO space
+ * @dev: PCI device to be initialized
+ *
+ *  Initialize device before it's used by a driver. Ask low-level code
+ *  to enable I/O resources. Wake up the device if it was suspended.
+ *  Beware, this function can fail.
+ */
+int pci_enable_device_io(struct pci_dev *dev)
+{
+	return __pci_enable_device_flags(dev, IORESOURCE_IO);
+}
+
+/**
+ * pci_enable_device_mem - Initialize a device for use with Memory space
+ * @dev: PCI device to be initialized
+ *
+ *  Initialize device before it's used by a driver. Ask low-level code
+ *  to enable Memory resources. Wake up the device if it was suspended.
+ *  Beware, this function can fail.
+ */
+int pci_enable_device_mem(struct pci_dev *dev)
+{
+	return __pci_enable_device_flags(dev, IORESOURCE_MEM);
+}
+
 /**
  * pci_enable_device - Initialize device before it's used by a driver.
  * @dev: PCI device to be initialized
@@ -749,7 +794,7 @@ pci_enable_device_bars(struct pci_dev *d
  */
 int pci_enable_device(struct pci_dev *dev)
 {
-	return pci_enable_device_bars(dev, (1 << PCI_NUM_RESOURCES) - 1);
+	return __pci_enable_device_flags(dev, IORESOURCE_MEM | IORESOURCE_IO);
 }
 
 /*
@@ -1621,6 +1666,8 @@ device_initcall(pci_init);
 EXPORT_SYMBOL_GPL(pci_restore_bars);
 EXPORT_SYMBOL(pci_reenable_device);
 EXPORT_SYMBOL(pci_enable_device_bars);
+EXPORT_SYMBOL(pci_enable_device_io);
+EXPORT_SYMBOL(pci_enable_device_mem);
 EXPORT_SYMBOL(pci_enable_device);
 EXPORT_SYMBOL(pcim_enable_device);
 EXPORT_SYMBOL(pcim_pin_device);
Index: linux-work/include/linux/pci.h
===================================================================
--- linux-work.orig/include/linux/pci.h	2007-12-18 11:00:32.000000000 +1100
+++ linux-work/include/linux/pci.h	2007-12-18 11:00:33.000000000 +1100
@@ -548,6 +548,8 @@ static inline int pci_write_config_dword
 
 int __must_check pci_enable_device(struct pci_dev *dev);
 int __must_check pci_enable_device_bars(struct pci_dev *dev, int mask);
+int __must_check pci_enable_device_io(struct pci_dev *dev);
+int __must_check pci_enable_device_mem(struct pci_dev *dev);
 int __must_check pci_reenable_device(struct pci_dev *);
 int __must_check pcim_enable_device(struct pci_dev *pdev);
 void pcim_pin_device(struct pci_dev *pdev);


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