linux-kernel - [PATCH V7 04/11] pci: Add new function to unmap IO resources.

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Date:	Tue, 10 May 2016 17:19:54 +0200
From:	Tomasz Nowicki <tn@...ihalf.com>
To:	helgaas@...nel.org, arnd@...db.de, will.deacon@....com,
	catalin.marinas@....com, rafael@...nel.org, hanjun.guo@...aro.org,
	Lorenzo.Pieralisi@....com, okaya@...eaurora.org,
	jchandra@...adcom.com
Cc:	robert.richter@...iumnetworks.com, mw@...ihalf.com,
	Liviu.Dudau@....com, ddaney@...iumnetworks.com,
	wangyijing@...wei.com, Suravee.Suthikulpanit@....com,
	msalter@...hat.com, linux-pci@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org, linaro-acpi@...ts.linaro.org,
	jcm@...hat.com, andrea.gallo@...aro.org, dhdang@....com,
	jeremy.linton@....com, liudongdong3@...wei.com, cov@...eaurora.org,
	Tomasz Nowicki <tn@...ihalf.com>
Subject: [PATCH V7 04/11] pci: Add new function to unmap IO resources.

It is very useful to release I/O resources so that the same I/O resources
can be allocated again (pci_remap_iospace), like in PCI hotplug removal
scenario. Therefore this patch implements new pci_unmap_iospace call which
unmaps I/O space as the symmetry to pci_remap_iospace.

Signed-off-by: Sinan Kaya <okaya@...eaurora.org>
Signed-off-by: Tomasz Nowicki <tn@...ihalf.com>
---
 drivers/pci/pci.c   | 24 ++++++++++++++++++++++++
 include/linux/pci.h |  1 +
 2 files changed, 25 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index bc0c914..ff97a0b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -25,6 +25,7 @@
 #include <linux/device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pci_hotplug.h>
+#include <linux/vmalloc.h>
 #include <asm/setup.h>
 #include <linux/aer.h>
 #include "pci.h"
@@ -3167,6 +3168,29 @@ int __weak pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr)
 #endif
 }
 
+/**
+ *	pci_unmap_iospace - Unmap the memory mapped I/O space
+ *	@res: resource to be unmapped
+ *
+ *	Unmap the CPU virtual address @res from virtual address space.
+ *	Only architectures that have memory mapped IO functions defined
+ *	(and the PCI_IOBASE value defined) should call this function.
+ */
+void  pci_unmap_iospace(struct resource *res)
+{
+#if defined(PCI_IOBASE) && defined(CONFIG_MMU)
+	unsigned long vaddr = (unsigned long)PCI_IOBASE + res->start;
+
+	unmap_kernel_range(vaddr, resource_size(res));
+#else
+	/*
+	 * This architecture does not have memory mapped I/O space,
+	 * so this function should never be called.
+	 */
+	WARN_ONCE(1, "This architecture does not support memory mapped I/O\n");
+#endif
+}
+
 static void __pci_set_master(struct pci_dev *dev, bool enable)
 {
 	u16 old_cmd, cmd;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d2a57f3..d6ea6ce 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1169,6 +1169,7 @@ int pci_register_io_range(phys_addr_t addr, resource_size_t size);
 unsigned long pci_address_to_pio(phys_addr_t addr);
 phys_addr_t pci_pio_to_address(unsigned long pio);
 int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
+void pci_unmap_iospace(struct resource *res);
 
 static inline pci_bus_addr_t pci_bus_address(struct pci_dev *pdev, int bar)
 {
-- 
1.9.1