pci root complex: support for tile architecture
This change enables PCI root complex support for TILEPro. Unlike
TILE-Gx, TILEPro has no support for memory-mapped I/O, so the PCI
support consists of hypervisor upcalls for PIO, DMA, etc. However,
the performance is fine for the devices we have tested with so far
(1Gb Ethernet, SATA, etc.).
The <asm/io.h> header was tweaked to be a little bit more aggressive
about disabling attempts to map/unmap IO port space. The hacky
<asm/pci-bridge.h> header was rolled into the <asm/pci.h> header
and the result was simplified. Both of the latter two headers were
preliminary versions not meant for release before now - oh well.
There is one quirk for our TILEmpower platform, which accidentally
negotiates up to 5GT and needs to be kicked down to 2.5GT.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
diff --git a/arch/tile/kernel/pci.c b/arch/tile/kernel/pci.c
new file mode 100644
index 0000000..a1ee25b
--- /dev/null
+++ b/arch/tile/kernel/pci.c
@@ -0,0 +1,621 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/capability.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/bootmem.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+
+#include <asm/processor.h>
+#include <asm/sections.h>
+#include <asm/byteorder.h>
+#include <asm/hv_driver.h>
+#include <hv/drv_pcie_rc_intf.h>
+
+
+/*
+ * Initialization flow and process
+ * -------------------------------
+ *
+ * This files containes the routines to search for PCI buses,
+ * enumerate the buses, and configure any attached devices.
+ *
+ * There are two entry points here:
+ * 1) tile_pci_init
+ * This sets up the pci_controller structs, and opens the
+ * FDs to the hypervisor. This is called from setup_arch() early
+ * in the boot process.
+ * 2) pcibios_init
+ * This probes the PCI bus(es) for any attached hardware. It's
+ * called by subsys_initcall. All of the real work is done by the
+ * generic Linux PCI layer.
+ *
+ */
+
+/*
+ * This flag tells if the platform is TILEmpower that needs
+ * special configuration for the PLX switch chip.
+ */
+int __write_once tile_plx_gen1;
+
+static struct pci_controller controllers[TILE_NUM_PCIE];
+static int num_controllers;
+
+static struct pci_ops tile_cfg_ops;
+
+
+/*
+ * We don't need to worry about the alignment of resources.
+ */
+resource_size_t pcibios_align_resource(void *data, const struct resource *res,
+ resource_size_t size, resource_size_t align)
+{
+ return res->start;
+}
+EXPORT_SYMBOL(pcibios_align_resource);
+
+/*
+ * Open a FD to the hypervisor PCI device.
+ *
+ * controller_id is the controller number, config type is 0 or 1 for
+ * config0 or config1 operations.
+ */
+static int __init tile_pcie_open(int controller_id, int config_type)
+{
+ char filename[32];
+ int fd;
+
+ sprintf(filename, "pcie/%d/config%d", controller_id, config_type);
+
+ fd = hv_dev_open((HV_VirtAddr)filename, 0);
+
+ return fd;
+}
+
+
+/*
+ * Get the IRQ numbers from the HV and set up the handlers for them.
+ */
+static int __init tile_init_irqs(int controller_id,
+ struct pci_controller *controller)
+{
+ char filename[32];
+ int fd;
+ int ret;
+ int x;
+ struct pcie_rc_config rc_config;
+
+ sprintf(filename, "pcie/%d/ctl", controller_id);
+ fd = hv_dev_open((HV_VirtAddr)filename, 0);
+ if (fd < 0) {
+ pr_err("PCI: hv_dev_open(%s) failed\n", filename);
+ return -1;
+ }
+ ret = hv_dev_pread(fd, 0, (HV_VirtAddr)(&rc_config),
+ sizeof(rc_config), PCIE_RC_CONFIG_MASK_OFF);
+ hv_dev_close(fd);
+ if (ret != sizeof(rc_config)) {
+ pr_err("PCI: wanted %zd bytes, got %d\n",
+ sizeof(rc_config), ret);
+ return -1;
+ }
+ /* Record irq_base so that we can map INTx to IRQ # later. */
+ controller->irq_base = rc_config.intr;
+
+ for (x = 0; x < 4; x++)
+ tile_irq_activate(rc_config.intr + x,
+ TILE_IRQ_HW_CLEAR);
+
+ if (rc_config.plx_gen1)
+ controller->plx_gen1 = 1;
+
+ return 0;
+}
+
+/*
+ * First initialization entry point, called from setup_arch().
+ *
+ * Find valid controllers and fill in pci_controller structs for each
+ * of them.
+ *
+ * Returns the number of controllers discovered.
+ */
+int __init tile_pci_init(void)
+{
+ int i;
+
+ pr_info("PCI: Searching for controllers...\n");
+
+ /* Do any configuration we need before using the PCIe */
+
+ for (i = 0; i < TILE_NUM_PCIE; i++) {
+ int hv_cfg_fd0 = -1;
+ int hv_cfg_fd1 = -1;
+ int hv_mem_fd = -1;
+ char name[32];
+ struct pci_controller *controller;
+
+ /*
+ * Open the fd to the HV. If it fails then this
+ * device doesn't exist.
+ */
+ hv_cfg_fd0 = tile_pcie_open(i, 0);
+ if (hv_cfg_fd0 < 0)
+ continue;
+ hv_cfg_fd1 = tile_pcie_open(i, 1);
+ if (hv_cfg_fd1 < 0) {
+ pr_err("PCI: Couldn't open config fd to HV "
+ "for controller %d\n", i);
+ goto err_cont;
+ }
+
+ sprintf(name, "pcie/%d/mem", i);
+ hv_mem_fd = hv_dev_open((HV_VirtAddr)name, 0);
+ if (hv_mem_fd < 0) {
+ pr_err("PCI: Could not open mem fd to HV!\n");
+ goto err_cont;
+ }
+
+ pr_info("PCI: Found PCI controller #%d\n", i);
+
+ controller = &controllers[num_controllers];
+
+ if (tile_init_irqs(i, controller)) {
+ pr_err("PCI: Could not initialize "
+ "IRQs, aborting.\n");
+ goto err_cont;
+ }
+
+ controller->index = num_controllers;
+ controller->hv_cfg_fd[0] = hv_cfg_fd0;
+ controller->hv_cfg_fd[1] = hv_cfg_fd1;
+ controller->hv_mem_fd = hv_mem_fd;
+ controller->first_busno = 0;
+ controller->last_busno = 0xff;
+ controller->ops = &tile_cfg_ops;
+
+ num_controllers++;
+ continue;
+
+err_cont:
+ if (hv_cfg_fd0 >= 0)
+ hv_dev_close(hv_cfg_fd0);
+ if (hv_cfg_fd1 >= 0)
+ hv_dev_close(hv_cfg_fd1);
+ if (hv_mem_fd >= 0)
+ hv_dev_close(hv_mem_fd);
+ continue;
+ }
+
+ /*
+ * Before using the PCIe, see if we need to do any platform-specific
+ * configuration, such as the PLX switch Gen 1 issue on TILEmpower.
+ */
+ for (i = 0; i < num_controllers; i++) {
+ struct pci_controller *controller = &controllers[i];
+
+ if (controller->plx_gen1)
+ tile_plx_gen1 = 1;
+ }
+
+ return num_controllers;
+}
+
+/*
+ * (pin - 1) converts from the PCI standard's [1:4] convention to
+ * a normal [0:3] range.
+ */
+static int tile_map_irq(struct pci_dev *dev, u8 slot, u8 pin)
+{
+ struct pci_controller *controller =
+ (struct pci_controller *)dev->sysdata;
+ return (pin - 1) + controller->irq_base;
+}
+
+
+static void __init fixup_read_and_payload_sizes(void)
+{
+ struct pci_dev *dev = NULL;
+ int smallest_max_payload = 0x1; /* Tile maxes out at 256 bytes. */
+ int max_read_size = 0x2; /* Limit to 512 byte reads. */
+ u16 new_values;
+
+ /* Scan for the smallest maximum payload size. */
+ while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+ int pcie_caps_offset;
+ u32 devcap;
+ int max_payload;
+
+ pcie_caps_offset = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (pcie_caps_offset == 0)
+ continue;
+
+ pci_read_config_dword(dev, pcie_caps_offset + PCI_EXP_DEVCAP,
+ &devcap);
+ max_payload = devcap & PCI_EXP_DEVCAP_PAYLOAD;
+ if (max_payload < smallest_max_payload)
+ smallest_max_payload = max_payload;
+ }
+
+ /* Now, set the max_payload_size for all devices to that value. */
+ new_values = (max_read_size << 12) | (smallest_max_payload << 5);
+ while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+ int pcie_caps_offset;
+ u16 devctl;
+
+ pcie_caps_offset = pci_find_capability(dev, PCI_CAP_ID_EXP);
+ if (pcie_caps_offset == 0)
+ continue;
+
+ pci_read_config_word(dev, pcie_caps_offset + PCI_EXP_DEVCTL,
+ &devctl);
+ devctl &= ~(PCI_EXP_DEVCTL_PAYLOAD | PCI_EXP_DEVCTL_READRQ);
+ devctl |= new_values;
+ pci_write_config_word(dev, pcie_caps_offset + PCI_EXP_DEVCTL,
+ devctl);
+ }
+}
+
+
+/*
+ * Second PCI initialization entry point, called by subsys_initcall.
+ *
+ * The controllers have been set up by the time we get here, by a call to
+ * tile_pci_init.
+ */
+static int __init pcibios_init(void)
+{
+ int i;
+
+ pr_info("PCI: Probing PCI hardware\n");
+
+ /*
+ * Delay a bit in case devices aren't ready. Some devices are
+ * known to require at least 20ms here, but we use a more
+ * conservative value.
+ */
+ mdelay(250);
+
+ /* Scan all of the recorded PCI controllers. */
+ for (i = 0; i < num_controllers; i++) {
+ struct pci_controller *controller = &controllers[i];
+ struct pci_bus *bus;
+
+ pr_info("PCI: initializing controller #%d\n", i);
+
+ /*
+ * This comes from the generic Linux PCI driver.
+ *
+ * It reads the PCI tree for this bus into the Linux
+ * data structures.
+ *
+ * This is inlined in linux/pci.h and calls into
+ * pci_scan_bus_parented() in probe.c.
+ */
+ bus = pci_scan_bus(0, controller->ops, controller);
+ controller->root_bus = bus;
+ controller->last_busno = bus->subordinate;
+
+ }
+
+ /* Do machine dependent PCI interrupt routing */
+ pci_fixup_irqs(pci_common_swizzle, tile_map_irq);
+
+ /*
+ * This comes from the generic Linux PCI driver.
+ *
+ * It allocates all of the resources (I/O memory, etc)
+ * associated with the devices read in above.
+ */
+
+ pci_assign_unassigned_resources();
+
+ /* Configure the max_read_size and max_payload_size values. */
+ fixup_read_and_payload_sizes();
+
+ /* Record the I/O resources in the PCI controller structure. */
+ for (i = 0; i < num_controllers; i++) {
+ struct pci_bus *root_bus = controllers[i].root_bus;
+ struct pci_bus *next_bus;
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &root_bus->devices, bus_list) {
+ /* Find the PCI host controller, ie. the 1st bridge. */
+ if ((dev->class >> 8) == PCI_CLASS_BRIDGE_PCI &&
+ (PCI_SLOT(dev->devfn) == 0)) {
+ next_bus = dev->subordinate;
+ controllers[i].mem_resources[0] =
+ *next_bus->resource[0];
+ controllers[i].mem_resources[1] =
+ *next_bus->resource[1];
+ controllers[i].mem_resources[2] =
+ *next_bus->resource[2];
+
+ break;
+ }
+ }
+
+ }
+
+ return 0;
+}
+subsys_initcall(pcibios_init);
+
+/*
+ * No bus fixups needed.
+ */
+void __devinit pcibios_fixup_bus(struct pci_bus *bus)
+{
+ /* Nothing needs to be done. */
+}
+
+/*
+ * This can be called from the generic PCI layer, but doesn't need to
+ * do anything.
+ */
+char __devinit *pcibios_setup(char *str)
+{
+ /* Nothing needs to be done. */
+ return str;
+}
+
+/*
+ * This is called from the generic Linux layer.
+ */
+void __init pcibios_update_irq(struct pci_dev *dev, int irq)
+{
+ pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
+}
+
+/*
+ * Enable memory and/or address decoding, as appropriate, for the
+ * device described by the 'dev' struct.
+ *
+ * This is called from the generic PCI layer, and can be called
+ * for bridges or endpoints.
+ */
+int pcibios_enable_device(struct pci_dev *dev, int mask)
+{
+ u16 cmd, old_cmd;
+ u8 header_type;
+ int i;
+ struct resource *r;
+
+ pci_read_config_byte(dev, PCI_HEADER_TYPE, &header_type);
+
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
+ old_cmd = cmd;
+ if ((header_type & 0x7F) == PCI_HEADER_TYPE_BRIDGE) {
+ /*
+ * For bridges, we enable both memory and I/O decoding
+ * in call cases.
+ */
+ cmd |= PCI_COMMAND_IO;
+ cmd |= PCI_COMMAND_MEMORY;
+ } else {
+ /*
+ * For endpoints, we enable memory and/or I/O decoding
+ * only if they have a memory resource of that type.
+ */
+ for (i = 0; i < 6; i++) {
+ r = &dev->resource[i];
+ if (r->flags & IORESOURCE_UNSET) {
+ pr_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;
+ }
+ }
+
+ /*
+ * We only write the command if it changed.
+ */
+ if (cmd != old_cmd)
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
+ return 0;
+}
+
+void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max)
+{
+ unsigned long start = pci_resource_start(dev, bar);
+ unsigned long len = pci_resource_len(dev, bar);
+ unsigned long flags = pci_resource_flags(dev, bar);
+
+ if (!len)
+ return NULL;
+ if (max && len > max)
+ len = max;
+
+ if (!(flags & IORESOURCE_MEM)) {
+ pr_info("PCI: Trying to map invalid resource %#lx\n", flags);
+ start = 0;
+ }
+
+ return (void __iomem *)start;
+}
+EXPORT_SYMBOL(pci_iomap);
+
+
+/****************************************************************
+ *
+ * Tile PCI config space read/write routines
+ *
+ ****************************************************************/
+
+/*
+ * These are the normal read and write ops
+ * These are expanded with macros from pci_bus_read_config_byte() etc.
+ *
+ * devfn is the combined PCI slot & function.
+ *
+ * offset is in bytes, from the start of config space for the
+ * specified bus & slot.
+ */
+
+static int __devinit tile_cfg_read(struct pci_bus *bus,
+ unsigned int devfn,
+ int offset,
+ int size,
+ u32 *val)
+{
+ struct pci_controller *controller = bus->sysdata;
+ int busnum = bus->number & 0xff;
+ int slot = (devfn >> 3) & 0x1f;
+ int function = devfn & 0x7;
+ u32 addr;
+ int config_mode = 1;
+
+ /*
+ * There is no bridge between the Tile and bus 0, so we
+ * use config0 to talk to bus 0.
+ *
+ * If we're talking to a bus other than zero then we
+ * must have found a bridge.
+ */
+ if (busnum == 0) {
+ /*
+ * We fake an empty slot for (busnum == 0) && (slot > 0),
+ * since there is only one slot on bus 0.
+ */
+ if (slot) {
+ *val = 0xFFFFFFFF;
+ return 0;
+ }
+ config_mode = 0;
+ }
+
+ addr = busnum << 20; /* Bus in 27:20 */
+ addr |= slot << 15; /* Slot (device) in 19:15 */
+ addr |= function << 12; /* Function is in 14:12 */
+ addr |= (offset & 0xFFF); /* byte address in 0:11 */
+
+ return hv_dev_pread(controller->hv_cfg_fd[config_mode], 0,
+ (HV_VirtAddr)(val), size, addr);
+}
+
+
+/*
+ * See tile_cfg_read() for relevent comments.
+ * Note that "val" is the value to write, not a pointer to that value.
+ */
+static int __devinit tile_cfg_write(struct pci_bus *bus,
+ unsigned int devfn,
+ int offset,
+ int size,
+ u32 val)
+{
+ struct pci_controller *controller = bus->sysdata;
+ int busnum = bus->number & 0xff;
+ int slot = (devfn >> 3) & 0x1f;
+ int function = devfn & 0x7;
+ u32 addr;
+ int config_mode = 1;
+ HV_VirtAddr valp = (HV_VirtAddr)&val;
+
+ /*
+ * For bus 0 slot 0 we use config 0 accesses.
+ */
+ if (busnum == 0) {
+ /*
+ * We fake an empty slot for (busnum == 0) && (slot > 0),
+ * since there is only one slot on bus 0.
+ */
+ if (slot)
+ return 0;
+ config_mode = 0;
+ }
+
+ addr = busnum << 20; /* Bus in 27:20 */
+ addr |= slot << 15; /* Slot (device) in 19:15 */
+ addr |= function << 12; /* Function is in 14:12 */
+ addr |= (offset & 0xFFF); /* byte address in 0:11 */
+
+#ifdef __BIG_ENDIAN
+ /* Point to the correct part of the 32-bit "val". */
+ valp += 4 - size;
+#endif
+
+ return hv_dev_pwrite(controller->hv_cfg_fd[config_mode], 0,
+ valp, size, addr);
+}
+
+
+static struct pci_ops tile_cfg_ops = {
+ .read = tile_cfg_read,
+ .write = tile_cfg_write,
+};
+
+
+/*
+ * In the following, each PCI controller's mem_resources[1]
+ * represents its (non-prefetchable) PCI memory resource.
+ * mem_resources[0] and mem_resources[2] refer to its PCI I/O and
+ * prefetchable PCI memory resources, respectively.
+ * For more details, see pci_setup_bridge() in setup-bus.c.
+ * By comparing the target PCI memory address against the
+ * end address of controller 0, we can determine the controller
+ * that should accept the PCI memory access.
+ */
+#define TILE_READ(size, type) \
+type _tile_read##size(unsigned long addr) \
+{ \
+ type val; \
+ int idx = 0; \
+ if (addr > controllers[0].mem_resources[1].end && \
+ addr > controllers[0].mem_resources[2].end) \
+ idx = 1; \
+ if (hv_dev_pread(controllers[idx].hv_mem_fd, 0, \
+ (HV_VirtAddr)(&val), sizeof(type), addr)) \
+ pr_err("PCI: read %zd bytes at 0x%lX failed\n", \
+ sizeof(type), addr); \
+ return val; \
+} \
+EXPORT_SYMBOL(_tile_read##size)
+
+TILE_READ(b, u8);
+TILE_READ(w, u16);
+TILE_READ(l, u32);
+TILE_READ(q, u64);
+
+#define TILE_WRITE(size, type) \
+void _tile_write##size(type val, unsigned long addr) \
+{ \
+ int idx = 0; \
+ if (addr > controllers[0].mem_resources[1].end && \
+ addr > controllers[0].mem_resources[2].end) \
+ idx = 1; \
+ if (hv_dev_pwrite(controllers[idx].hv_mem_fd, 0, \
+ (HV_VirtAddr)(&val), sizeof(type), addr)) \
+ pr_err("PCI: write %zd bytes at 0x%lX failed\n", \
+ sizeof(type), addr); \
+} \
+EXPORT_SYMBOL(_tile_write##size)
+
+TILE_WRITE(b, u8);
+TILE_WRITE(w, u16);
+TILE_WRITE(l, u32);
+TILE_WRITE(q, u64);