[PATCH V6 05/13] acpi, pci: Support IO resources when parsing PCI host bridge resources.

Tomasz Nowicki
2016-04-15T17:06:40Z

Platforms that have memory mapped IO port (such as ARM64) need special
handling for PCI I/O resources. For host bridge's resource probing case
these resources need to be fixed up with pci_register_io_range/pci_remap_iospace etc.

Furthermore, the same I/O resources need to be released after hotplug
removal so that it can be re-added back by the pci_remap_iospace
function during insertion. Therefore we implement new pci_unmap_iospace call
which unmaps I/O space as the symmetry to pci_remap_iospace.

Signed-off-by: Jayachandran C <jchandra@broadcom.com>
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
---
drivers/acpi/pci_root.c | 33 +++++++++++++++++++++++++++++++++
drivers/pci/pci.c | 24 ++++++++++++++++++++++++
include/linux/pci.h | 1 +
3 files changed, 58 insertions(+)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index d9a70c4..815b6ca 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -742,6 +742,34 @@ next:
resource_list_add_tail(entry, resources);
}
}
+static void acpi_pci_root_remap_iospace(struct resource_entry *entry)
+{
+#ifdef PCI_IOBASE
+ struct resource *res = entry->res;
+ resource_size_t cpu_addr = res->start;
+ resource_size_t pci_addr = cpu_addr - entry->offset;
+ resource_size_t length = resource_size(res);
+ unsigned long port;
+
+ if (pci_register_io_range(cpu_addr, length))
+ goto err;
+
+ port = pci_address_to_pio(cpu_addr);
+ if (port == (unsigned long)-1)
+ goto err;
+
+ res->start = port;
+ res->end = port + length - 1;
+ entry->offset = port - pci_addr;
+
+ if (pci_remap_iospace(res, cpu_addr) < 0)
+ goto err;
+ pr_info("Remapped I/O %pa to %pR\n", &cpu_addr, res);
+ return;
+err:
+ res->flags |= IORESOURCE_DISABLED;
+#endif
+}

int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
{
@@ -763,6 +791,9 @@ int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
"no IO and memory resources present in _CRS\n");
else {
resource_list_for_each_entry_safe(entry, tmp, list) {
+ if (entry->res->flags & IORESOURCE_IO)
+ acpi_pci_root_remap_iospace(entry);
+
if (entry->res->flags & IORESOURCE_DISABLED)
resource_list_destroy_entry(entry);
else
@@ -834,6 +865,8 @@ static void acpi_pci_root_release_info(struct pci_host_bridge *bridge)

resource_list_for_each_entry(entry, &bridge->windows) {
res = entry->res;
+ if (res->flags & IORESOURCE_IO)
+ pci_unmap_iospace(res);
if (res->parent &&
(res->flags & (IORESOURCE_MEM | IORESOURCE_IO)))
release_resource(res);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 89e9996..c0f8a4e 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -26,6 +26,7 @@
#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"
@@ -3168,6 +3169,29 @@ 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 c28adb4..df1f33d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1168,6 +1168,7 @@ 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