aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/kernel/bios32.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/kernel/bios32.c')
-rw-r--r--arch/arm/kernel/bios32.c699
1 files changed, 699 insertions, 0 deletions
diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
new file mode 100644
index 00000000000..ad26e98f1e6
--- /dev/null
+++ b/arch/arm/kernel/bios32.c
@@ -0,0 +1,699 @@
+/*
+ * linux/arch/arm/kernel/bios32.c
+ *
+ * PCI bios-type initialisation for PCI machines
+ *
+ * Bits taken from various places.
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+#include <asm/mach-types.h>
+#include <asm/mach/pci.h>
+
+static int debug_pci;
+static int use_firmware;
+
+/*
+ * We can't use pci_find_device() here since we are
+ * called from interrupt context.
+ */
+static void pcibios_bus_report_status(struct pci_bus *bus, u_int status_mask, int warn)
+{
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ u16 status;
+
+ /*
+ * ignore host bridge - we handle
+ * that separately
+ */
+ if (dev->bus->number == 0 && dev->devfn == 0)
+ continue;
+
+ pci_read_config_word(dev, PCI_STATUS, &status);
+ if (status == 0xffff)
+ continue;
+
+ if ((status & status_mask) == 0)
+ continue;
+
+ /* clear the status errors */
+ pci_write_config_word(dev, PCI_STATUS, status & status_mask);
+
+ if (warn)
+ printk("(%s: %04X) ", pci_name(dev), status);
+ }
+
+ list_for_each_entry(dev, &bus->devices, bus_list)
+ if (dev->subordinate)
+ pcibios_bus_report_status(dev->subordinate, status_mask, warn);
+}
+
+void pcibios_report_status(u_int status_mask, int warn)
+{
+ struct list_head *l;
+
+ list_for_each(l, &pci_root_buses) {
+ struct pci_bus *bus = pci_bus_b(l);
+
+ pcibios_bus_report_status(bus, status_mask, warn);
+ }
+}
+
+/*
+ * We don't use this to fix the device, but initialisation of it.
+ * It's not the correct use for this, but it works.
+ * Note that the arbiter/ISA bridge appears to be buggy, specifically in
+ * the following area:
+ * 1. park on CPU
+ * 2. ISA bridge ping-pong
+ * 3. ISA bridge master handling of target RETRY
+ *
+ * Bug 3 is responsible for the sound DMA grinding to a halt. We now
+ * live with bug 2.
+ */
+static void __devinit pci_fixup_83c553(struct pci_dev *dev)
+{
+ /*
+ * Set memory region to start at address 0, and enable IO
+ */
+ pci_write_config_dword(dev, PCI_BASE_ADDRESS_0, PCI_BASE_ADDRESS_SPACE_MEMORY);
+ pci_write_config_word(dev, PCI_COMMAND, PCI_COMMAND_IO);
+
+ dev->resource[0].end -= dev->resource[0].start;
+ dev->resource[0].start = 0;
+
+ /*
+ * All memory requests from ISA to be channelled to PCI
+ */
+ pci_write_config_byte(dev, 0x48, 0xff);
+
+ /*
+ * Enable ping-pong on bus master to ISA bridge transactions.
+ * This improves the sound DMA substantially. The fixed
+ * priority arbiter also helps (see below).
+ */
+ pci_write_config_byte(dev, 0x42, 0x01);
+
+ /*
+ * Enable PCI retry
+ */
+ pci_write_config_byte(dev, 0x40, 0x22);
+
+ /*
+ * We used to set the arbiter to "park on last master" (bit
+ * 1 set), but unfortunately the CyberPro does not park the
+ * bus. We must therefore park on CPU. Unfortunately, this
+ * may trigger yet another bug in the 553.
+ */
+ pci_write_config_byte(dev, 0x83, 0x02);
+
+ /*
+ * Make the ISA DMA request lowest priority, and disable
+ * rotating priorities completely.
+ */
+ pci_write_config_byte(dev, 0x80, 0x11);
+ pci_write_config_byte(dev, 0x81, 0x00);
+
+ /*
+ * Route INTA input to IRQ 11, and set IRQ11 to be level
+ * sensitive.
+ */
+ pci_write_config_word(dev, 0x44, 0xb000);
+ outb(0x08, 0x4d1);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_83C553, pci_fixup_83c553);
+
+static void __devinit pci_fixup_unassign(struct pci_dev *dev)
+{
+ dev->resource[0].end -= dev->resource[0].start;
+ dev->resource[0].start = 0;
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND2, PCI_DEVICE_ID_WINBOND2_89C940F, pci_fixup_unassign);
+
+/*
+ * Prevent the PCI layer from seeing the resources allocated to this device
+ * if it is the host bridge by marking it as such. These resources are of
+ * no consequence to the PCI layer (they are handled elsewhere).
+ */
+static void __devinit pci_fixup_dec21285(struct pci_dev *dev)
+{
+ int i;
+
+ if (dev->devfn == 0) {
+ dev->class &= 0xff;
+ dev->class |= PCI_CLASS_BRIDGE_HOST << 8;
+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+ dev->resource[i].start = 0;
+ dev->resource[i].end = 0;
+ dev->resource[i].flags = 0;
+ }
+ }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_DEC, PCI_DEVICE_ID_DEC_21285, pci_fixup_dec21285);
+
+/*
+ * Same as above. The PrPMC800 carrier board for the PrPMC1100
+ * card maps the host-bridge @ 00:01:00 for some reason and it
+ * ends up getting scanned. Note that we only want to do this
+ * fixup when we find the IXP4xx on a PrPMC system, which is why
+ * we check the machine type. We could be running on a board
+ * with an IXP4xx target device and we don't want to kill the
+ * resources in that case.
+ */
+static void __devinit pci_fixup_prpmc1100(struct pci_dev *dev)
+{
+ int i;
+
+ if (machine_is_prpmc1100()) {
+ dev->class &= 0xff;
+ dev->class |= PCI_CLASS_BRIDGE_HOST << 8;
+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+ dev->resource[i].start = 0;
+ dev->resource[i].end = 0;
+ dev->resource[i].flags = 0;
+ }
+ }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IXP4XX, pci_fixup_prpmc1100);
+
+/*
+ * PCI IDE controllers use non-standard I/O port decoding, respect it.
+ */
+static void __devinit pci_fixup_ide_bases(struct pci_dev *dev)
+{
+ struct resource *r;
+ int i;
+
+ if ((dev->class >> 8) != PCI_CLASS_STORAGE_IDE)
+ return;
+
+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+ r = dev->resource + i;
+ if ((r->start & ~0x80) == 0x374) {
+ r->start |= 2;
+ r->end = r->start;
+ }
+ }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pci_fixup_ide_bases);
+
+/*
+ * Put the DEC21142 to sleep
+ */
+static void __devinit pci_fixup_dec21142(struct pci_dev *dev)
+{
+ pci_write_config_dword(dev, 0x40, 0x80000000);
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_DEC, PCI_DEVICE_ID_DEC_21142, pci_fixup_dec21142);
+
+/*
+ * The CY82C693 needs some rather major fixups to ensure that it does
+ * the right thing. Idea from the Alpha people, with a few additions.
+ *
+ * We ensure that the IDE base registers are set to 1f0/3f4 for the
+ * primary bus, and 170/374 for the secondary bus. Also, hide them
+ * from the PCI subsystem view as well so we won't try to perform
+ * our own auto-configuration on them.
+ *
+ * In addition, we ensure that the PCI IDE interrupts are routed to
+ * IRQ 14 and IRQ 15 respectively.
+ *
+ * The above gets us to a point where the IDE on this device is
+ * functional. However, The CY82C693U _does not work_ in bus
+ * master mode without locking the PCI bus solid.
+ */
+static void __devinit pci_fixup_cy82c693(struct pci_dev *dev)
+{
+ if ((dev->class >> 8) == PCI_CLASS_STORAGE_IDE) {
+ u32 base0, base1;
+
+ if (dev->class & 0x80) { /* primary */
+ base0 = 0x1f0;
+ base1 = 0x3f4;
+ } else { /* secondary */
+ base0 = 0x170;
+ base1 = 0x374;
+ }
+
+ pci_write_config_dword(dev, PCI_BASE_ADDRESS_0,
+ base0 | PCI_BASE_ADDRESS_SPACE_IO);
+ pci_write_config_dword(dev, PCI_BASE_ADDRESS_1,
+ base1 | PCI_BASE_ADDRESS_SPACE_IO);
+
+ dev->resource[0].start = 0;
+ dev->resource[0].end = 0;
+ dev->resource[0].flags = 0;
+
+ dev->resource[1].start = 0;
+ dev->resource[1].end = 0;
+ dev->resource[1].flags = 0;
+ } else if (PCI_FUNC(dev->devfn) == 0) {
+ /*
+ * Setup IDE IRQ routing.
+ */
+ pci_write_config_byte(dev, 0x4b, 14);
+ pci_write_config_byte(dev, 0x4c, 15);
+
+ /*
+ * Disable FREQACK handshake, enable USB.
+ */
+ pci_write_config_byte(dev, 0x4d, 0x41);
+
+ /*
+ * Enable PCI retry, and PCI post-write buffer.
+ */
+ pci_write_config_byte(dev, 0x44, 0x17);
+
+ /*
+ * Enable ISA master and DMA post write buffering.
+ */
+ pci_write_config_byte(dev, 0x45, 0x03);
+ }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_CONTAQ, PCI_DEVICE_ID_CONTAQ_82C693, pci_fixup_cy82c693);
+
+void __devinit pcibios_update_irq(struct pci_dev *dev, int irq)
+{
+ if (debug_pci)
+ printk("PCI: Assigning IRQ %02d to %s\n", irq, pci_name(dev));
+ pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
+}
+
+/*
+ * If the bus contains any of these devices, then we must not turn on
+ * parity checking of any kind. Currently this is CyberPro 20x0 only.
+ */
+static inline int pdev_bad_for_parity(struct pci_dev *dev)
+{
+ return (dev->vendor == PCI_VENDOR_ID_INTERG &&
+ (dev->device == PCI_DEVICE_ID_INTERG_2000 ||
+ dev->device == PCI_DEVICE_ID_INTERG_2010));
+}
+
+/*
+ * Adjust the device resources from bus-centric to Linux-centric.
+ */
+static void __devinit
+pdev_fixup_device_resources(struct pci_sys_data *root, struct pci_dev *dev)
+{
+ unsigned long offset;
+ int i;
+
+ for (i = 0; i < PCI_NUM_RESOURCES; i++) {
+ if (dev->resource[i].start == 0)
+ continue;
+ if (dev->resource[i].flags & IORESOURCE_MEM)
+ offset = root->mem_offset;
+ else
+ offset = root->io_offset;
+
+ dev->resource[i].start += offset;
+ dev->resource[i].end += offset;
+ }
+}
+
+static void __devinit
+pbus_assign_bus_resources(struct pci_bus *bus, struct pci_sys_data *root)
+{
+ struct pci_dev *dev = bus->self;
+ int i;
+
+ if (!dev) {
+ /*
+ * Assign root bus resources.
+ */
+ for (i = 0; i < 3; i++)
+ bus->resource[i] = root->resource[i];
+ }
+}
+
+/*
+ * pcibios_fixup_bus - Called after each bus is probed,
+ * but before its children are examined.
+ */
+void __devinit pcibios_fixup_bus(struct pci_bus *bus)
+{
+ struct pci_sys_data *root = bus->sysdata;
+ struct pci_dev *dev;
+ u16 features = PCI_COMMAND_SERR | PCI_COMMAND_PARITY | PCI_COMMAND_FAST_BACK;
+
+ pbus_assign_bus_resources(bus, root);
+
+ /*
+ * Walk the devices on this bus, working out what we can
+ * and can't support.
+ */
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ u16 status;
+
+ pdev_fixup_device_resources(root, dev);
+
+ pci_read_config_word(dev, PCI_STATUS, &status);
+
+ /*
+ * If any device on this bus does not support fast back
+ * to back transfers, then the bus as a whole is not able
+ * to support them. Having fast back to back transfers
+ * on saves us one PCI cycle per transaction.
+ */
+ if (!(status & PCI_STATUS_FAST_BACK))
+ features &= ~PCI_COMMAND_FAST_BACK;
+
+ if (pdev_bad_for_parity(dev))
+ features &= ~(PCI_COMMAND_SERR | PCI_COMMAND_PARITY);
+
+ switch (dev->class >> 8) {
+#if defined(CONFIG_ISA) || defined(CONFIG_EISA)
+ case PCI_CLASS_BRIDGE_ISA:
+ case PCI_CLASS_BRIDGE_EISA:
+ /*
+ * If this device is an ISA bridge, set isa_bridge
+ * to point at this device. We will then go looking
+ * for things like keyboard, etc.
+ */
+ isa_bridge = dev;
+ break;
+#endif
+ case PCI_CLASS_BRIDGE_PCI:
+ pci_read_config_word(dev, PCI_BRIDGE_CONTROL, &status);
+ status |= PCI_BRIDGE_CTL_PARITY|PCI_BRIDGE_CTL_MASTER_ABORT;
+ status &= ~(PCI_BRIDGE_CTL_BUS_RESET|PCI_BRIDGE_CTL_FAST_BACK);
+ pci_write_config_word(dev, PCI_BRIDGE_CONTROL, status);
+ break;
+
+ case PCI_CLASS_BRIDGE_CARDBUS:
+ pci_read_config_word(dev, PCI_CB_BRIDGE_CONTROL, &status);
+ status |= PCI_CB_BRIDGE_CTL_PARITY|PCI_CB_BRIDGE_CTL_MASTER_ABORT;
+ pci_write_config_word(dev, PCI_CB_BRIDGE_CONTROL, status);
+ break;
+ }
+ }
+
+ /*
+ * Now walk the devices again, this time setting them up.
+ */
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ u16 cmd;
+
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
+ cmd |= features;
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
+
+ pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE,
+ L1_CACHE_BYTES >> 2);
+ }
+
+ /*
+ * Propagate the flags to the PCI bridge.
+ */
+ if (bus->self && bus->self->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ if (features & PCI_COMMAND_FAST_BACK)
+ bus->bridge_ctl |= PCI_BRIDGE_CTL_FAST_BACK;
+ if (features & PCI_COMMAND_PARITY)
+ bus->bridge_ctl |= PCI_BRIDGE_CTL_PARITY;
+ }
+
+ /*
+ * Report what we did for this bus
+ */
+ printk(KERN_INFO "PCI: bus%d: Fast back to back transfers %sabled\n",
+ bus->number, (features & PCI_COMMAND_FAST_BACK) ? "en" : "dis");
+}
+
+/*
+ * Convert from Linux-centric to bus-centric addresses for bridge devices.
+ */
+void __devinit
+pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
+ struct resource *res)
+{
+ struct pci_sys_data *root = dev->sysdata;
+ unsigned long offset = 0;
+
+ if (res->flags & IORESOURCE_IO)
+ offset = root->io_offset;
+ if (res->flags & IORESOURCE_MEM)
+ offset = root->mem_offset;
+
+ region->start = res->start - offset;
+ region->end = res->end - offset;
+}
+
+#ifdef CONFIG_HOTPLUG
+EXPORT_SYMBOL(pcibios_fixup_bus);
+EXPORT_SYMBOL(pcibios_resource_to_bus);
+#endif
+
+/*
+ * This is the standard PCI-PCI bridge swizzling algorithm:
+ *
+ * Dev: 0 1 2 3
+ * A A B C D
+ * B B C D A
+ * C C D A B
+ * D D A B C
+ * ^^^^^^^^^^ irq pin on bridge
+ */
+u8 __devinit pci_std_swizzle(struct pci_dev *dev, u8 *pinp)
+{
+ int pin = *pinp - 1;
+
+ while (dev->bus->self) {
+ pin = (pin + PCI_SLOT(dev->devfn)) & 3;
+ /*
+ * move up the chain of bridges,
+ * swizzling as we go.
+ */
+ dev = dev->bus->self;
+ }
+ *pinp = pin + 1;
+
+ return PCI_SLOT(dev->devfn);
+}
+
+/*
+ * Swizzle the device pin each time we cross a bridge.
+ * This might update pin and returns the slot number.
+ */
+static u8 __devinit pcibios_swizzle(struct pci_dev *dev, u8 *pin)
+{
+ struct pci_sys_data *sys = dev->sysdata;
+ int slot = 0, oldpin = *pin;
+
+ if (sys->swizzle)
+ slot = sys->swizzle(dev, pin);
+
+ if (debug_pci)
+ printk("PCI: %s swizzling pin %d => pin %d slot %d\n",
+ pci_name(dev), oldpin, *pin, slot);
+
+ return slot;
+}
+
+/*
+ * Map a slot/pin to an IRQ.
+ */
+static int pcibios_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
+{
+ struct pci_sys_data *sys = dev->sysdata;
+ int irq = -1;
+
+ if (sys->map_irq)
+ irq = sys->map_irq(dev, slot, pin);
+
+ if (debug_pci)
+ printk("PCI: %s mapping slot %d pin %d => irq %d\n",
+ pci_name(dev), slot, pin, irq);
+
+ return irq;
+}
+
+static void __init pcibios_init_hw(struct hw_pci *hw)
+{
+ struct pci_sys_data *sys = NULL;
+ int ret;
+ int nr, busnr;
+
+ for (nr = busnr = 0; nr < hw->nr_controllers; nr++) {
+ sys = kmalloc(sizeof(struct pci_sys_data), GFP_KERNEL);
+ if (!sys)
+ panic("PCI: unable to allocate sys data!");
+
+ memset(sys, 0, sizeof(struct pci_sys_data));
+
+ sys->hw = hw;
+ sys->busnr = busnr;
+ sys->swizzle = hw->swizzle;
+ sys->map_irq = hw->map_irq;
+ sys->resource[0] = &ioport_resource;
+ sys->resource[1] = &iomem_resource;
+
+ ret = hw->setup(nr, sys);
+
+ if (ret > 0) {
+ sys->bus = hw->scan(nr, sys);
+
+ if (!sys->bus)
+ panic("PCI: unable to scan bus!");
+
+ busnr = sys->bus->subordinate + 1;
+
+ list_add(&sys->node, &hw->buses);
+ } else {
+ kfree(sys);
+ if (ret < 0)
+ break;
+ }
+ }
+}
+
+void __init pci_common_init(struct hw_pci *hw)
+{
+ struct pci_sys_data *sys;
+
+ INIT_LIST_HEAD(&hw->buses);
+
+ if (hw->preinit)
+ hw->preinit();
+ pcibios_init_hw(hw);
+ if (hw->postinit)
+ hw->postinit();
+
+ pci_fixup_irqs(pcibios_swizzle, pcibios_map_irq);
+
+ list_for_each_entry(sys, &hw->buses, node) {
+ struct pci_bus *bus = sys->bus;
+
+ if (!use_firmware) {
+ /*
+ * Size the bridge windows.
+ */
+ pci_bus_size_bridges(bus);
+
+ /*
+ * Assign resources.
+ */
+ pci_bus_assign_resources(bus);
+ }
+
+ /*
+ * Tell drivers about devices found.
+ */
+ pci_bus_add_devices(bus);
+ }
+}
+
+char * __init pcibios_setup(char *str)
+{
+ if (!strcmp(str, "debug")) {
+ debug_pci = 1;
+ return NULL;
+ } else if (!strcmp(str, "firmware")) {
+ use_firmware = 1;
+ return NULL;
+ }
+ return str;
+}
+
+/*
+ * From arch/i386/kernel/pci-i386.c:
+ *
+ * We need to avoid collisions with `mirrored' VGA ports
+ * and other strange ISA hardware, so we always want the
+ * addresses to be allocated in the 0x000-0x0ff region
+ * modulo 0x400.
+ *
+ * Why? Because some silly external IO cards only decode
+ * the low 10 bits of the IO address. The 0x00-0xff region
+ * is reserved for motherboard devices that decode all 16
+ * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
+ * but we want to try to avoid allocating at 0x2900-0x2bff
+ * which might be mirrored at 0x0100-0x03ff..
+ */
+void pcibios_align_resource(void *data, struct resource *res,
+ unsigned long size, unsigned long align)
+{
+ unsigned long start = res->start;
+
+ if (res->flags & IORESOURCE_IO && start & 0x300)
+ start = (start + 0x3ff) & ~0x3ff;
+
+ res->start = (start + align - 1) & ~(align - 1);
+}
+
+/**
+ * pcibios_enable_device - Enable I/O and memory.
+ * @dev: PCI device to be enabled
+ */
+int pcibios_enable_device(struct pci_dev *dev, int mask)
+{
+ u16 cmd, old_cmd;
+ int idx;
+ struct resource *r;
+
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
+ old_cmd = cmd;
+ for (idx = 0; idx < 6; idx++) {
+ /* Only set up the requested stuff */
+ if (!(mask & (1 << idx)))
+ continue;
+
+ r = dev->resource + idx;
+ if (!r->start && r->end) {
+ printk(KERN_ERR "PCI: Device %s not available because"
+ " of resource collisions\n", pci_name(dev));
+ return -EINVAL;
+ }
+ if (r->flags & IORESOURCE_IO)
+ cmd |= PCI_COMMAND_IO;
+ if (r->flags & IORESOURCE_MEM)
+ cmd |= PCI_COMMAND_MEMORY;
+ }
+
+ /*
+ * Bridges (eg, cardbus bridges) need to be fully enabled
+ */
+ if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
+ cmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
+
+ if (cmd != old_cmd) {
+ printk("PCI: enabling device %s (%04x -> %04x)\n",
+ pci_name(dev), old_cmd, cmd);
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
+ }
+ return 0;
+}
+
+int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
+ enum pci_mmap_state mmap_state, int write_combine)
+{
+ struct pci_sys_data *root = dev->sysdata;
+ unsigned long phys;
+
+ if (mmap_state == pci_mmap_io) {
+ return -EINVAL;
+ } else {
+ phys = vma->vm_pgoff + (root->mem_offset >> PAGE_SHIFT);
+ }
+
+ /*
+ * Mark this as IO
+ */
+ vma->vm_flags |= VM_SHM | VM_LOCKED | VM_IO;
+ vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+ if (remap_pfn_range(vma, vma->vm_start, phys,
+ vma->vm_end - vma->vm_start,
+ vma->vm_page_prot))
+ return -EAGAIN;
+
+ return 0;
+}