[RESEND PATCH 2/3] PCI: ARM: add support for generic PCI host controller
Will Deacon
will.deacon at arm.com
Tue May 6 11:38:12 PDT 2014
On Fri, May 02, 2014 at 08:29:30PM +0100, Arnd Bergmann wrote:
> On Friday 02 May 2014 13:03:18 Jason Gunthorpe wrote:
> > > Given that the idea was to separate setup() and probe(), I didn't want to
> > > make the assumption that I was called in probe context.
> >
> > It doesn't matter for this driver, but look at mvebu, you cannot move
> > the interrupt, gpio and clock acquisitions from probe() to setup(), as
> > they could all trigger a defered probe. Better to be consistent,
> > especially if this is the golden reference driver we want everyone to
> > follow (sorry Will)
>
> Fair enough. It shouldn't be hard to move.
[...]
> It should be fine to have a trivial setup function like this
>
> static int gen_pci_setup(int nr, struct pci_sys_data *sys)
> {
> struct gen_pci *pci = sys->private_data;
> list_splice_init(pci->resource, sys->resources);
> return 1;
> }
>
> and do everything in probe().
Ok, I've respun the patch and included it below. It's turned probe() into a
bit of a beast, but the cleanup is a lot simpler (unless I'm missing
something).
Will
--->8
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
new file mode 100644
index 000000000000..199a8795cb77
--- /dev/null
+++ b/drivers/pci/host/pci-host-generic.c
@@ -0,0 +1,361 @@
+/*
+ * Simple, generic PCI host controller driver targetting firmware-initialised
+ * systems and virtual machines (e.g. the PCI emulation provided by kvmtool).
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) 2014 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon at arm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+#include <linux/platform_device.h>
+
+struct gen_pci_cfg_bus_ops {
+ u32 bus_shift;
+ void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int);
+};
+
+struct gen_pci_cfg_windows {
+ struct resource res;
+ struct resource bus_range;
+ void __iomem **win;
+
+ const struct gen_pci_cfg_bus_ops *ops;
+};
+
+struct gen_pci {
+ struct pci_host_bridge host;
+ struct gen_pci_cfg_windows cfg;
+ struct list_head resources;
+};
+
+static void __iomem *gen_pci_map_cfg_bus_cam(struct pci_bus *bus,
+ unsigned int devfn,
+ int where)
+{
+ struct pci_sys_data *sys = bus->sysdata;
+ struct gen_pci *pci = sys->private_data;
+ resource_size_t idx = bus->number - pci->cfg.bus_range.start;
+
+ return pci->cfg.win[idx] + ((devfn << 8) | where);
+}
+
+static struct gen_pci_cfg_bus_ops gen_pci_cfg_cam_bus_ops = {
+ .bus_shift = 16,
+ .map_bus = gen_pci_map_cfg_bus_cam,
+};
+
+static void __iomem *gen_pci_map_cfg_bus_ecam(struct pci_bus *bus,
+ unsigned int devfn,
+ int where)
+{
+ struct pci_sys_data *sys = bus->sysdata;
+ struct gen_pci *pci = sys->private_data;
+ resource_size_t idx = bus->number - pci->cfg.bus_range.start;
+
+ return pci->cfg.win[idx] + ((devfn << 12) | where);
+}
+
+static struct gen_pci_cfg_bus_ops gen_pci_cfg_ecam_bus_ops = {
+ .bus_shift = 20,
+ .map_bus = gen_pci_map_cfg_bus_ecam,
+};
+
+static int gen_pci_config_read(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 *val)
+{
+ void __iomem *addr;
+ struct pci_sys_data *sys = bus->sysdata;
+ struct gen_pci *pci = sys->private_data;
+
+ addr = pci->cfg.ops->map_bus(bus, devfn, where);
+
+ switch (size) {
+ case 1:
+ *val = readb(addr);
+ break;
+ case 2:
+ *val = readw(addr);
+ break;
+ default:
+ *val = readl(addr);
+ }
+
+ return PCIBIOS_SUCCESSFUL;
+}
+
+static int gen_pci_config_write(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ void __iomem *addr;
+ struct pci_sys_data *sys = bus->sysdata;
+ struct gen_pci *pci = sys->private_data;
+
+ addr = pci->cfg.ops->map_bus(bus, devfn, where);
+
+ switch (size) {
+ case 1:
+ writeb(val, addr);
+ break;
+ case 2:
+ writew(val, addr);
+ break;
+ default:
+ writel(val, addr);
+ }
+
+ return PCIBIOS_SUCCESSFUL;
+}
+
+static struct pci_ops gen_pci_ops = {
+ .read = gen_pci_config_read,
+ .write = gen_pci_config_write,
+};
+
+static int gen_pci_calc_io_offset(struct device *dev,
+ struct of_pci_range *range,
+ struct resource *res,
+ resource_size_t *offset)
+{
+ static atomic_t wins = ATOMIC_INIT(0);
+ int err, idx, max_win;
+ unsigned int window;
+
+ if (!PAGE_ALIGNED(range->cpu_addr))
+ return -EINVAL;
+
+ max_win = (IO_SPACE_LIMIT + 1) / SZ_64K;
+ idx = atomic_inc_return(&wins);
+ if (idx >= max_win)
+ return -ENOSPC;
+
+ window = (idx - 1) * SZ_64K;
+ err = pci_ioremap_io(window, range->cpu_addr);
+ if (err)
+ return err;
+
+ of_pci_range_to_resource(range, dev->of_node, res);
+ res->start = window;
+ res->end = res->start + range->size - 1;
+ *offset = window - range->pci_addr;
+ return 0;
+}
+
+static int gen_pci_calc_mem_offset(struct device *dev,
+ struct of_pci_range *range,
+ struct resource *res,
+ resource_size_t *offset)
+{
+ of_pci_range_to_resource(range, dev->of_node, res);
+ *offset = range->cpu_addr - range->pci_addr;
+ return 0;
+}
+
+static const struct of_device_id gen_pci_of_match[] = {
+ { .compatible = "pci-host-cam-generic",
+ .data = &gen_pci_cfg_cam_bus_ops },
+
+ { .compatible = "pci-host-ecam-generic",
+ .data = &gen_pci_cfg_ecam_bus_ops },
+
+ { },
+};
+MODULE_DEVICE_TABLE(of, gen_pci_of_match);
+
+static int gen_pci_setup(int nr, struct pci_sys_data *sys)
+{
+ struct gen_pci *pci = sys->private_data;
+ list_splice_init(&pci->resources, &sys->resources);
+ return 1;
+}
+
+static int gen_pci_probe(struct platform_device *pdev)
+{
+ struct gen_pci *pci;
+ int err, res_valid;
+ struct pci_host_bridge_window *win;
+ struct resource *bus_range;
+ resource_size_t busn;
+ const char *type;
+ struct of_pci_range range;
+ struct of_pci_range_parser parser;
+ struct hw_pci hw;
+ const struct of_device_id *of_id;
+ const int *prop;
+ u8 bus_max;
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+
+ if (!dev->of_node)
+ return -ENODEV;
+
+ pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
+ if (!pci)
+ return -ENOMEM;
+
+ pci->host.dev.parent = dev;
+ hw = (struct hw_pci) {
+ .nr_controllers = 1,
+ .private_data = (void **)&pci,
+ .setup = gen_pci_setup,
+ .map_irq = of_irq_parse_and_map_pci,
+ .ops = &gen_pci_ops,
+ };
+
+ type = of_get_property(np, "device_type", NULL);
+ if (!type || strcmp(type, "pci")) {
+ dev_err(dev, "invalid \"device_type\" %s\n", type);
+ return -EINVAL;
+ }
+
+ if (of_pci_range_parser_init(&parser, np)) {
+ dev_err(dev, "missing \"ranges\" property\n");
+ return -EINVAL;
+ }
+
+ prop = of_get_property(of_chosen, "linux,pci-probe-only", NULL);
+ if (prop) {
+ if (*prop)
+ pci_add_flags(PCI_PROBE_ONLY);
+ else
+ pci_clear_flags(PCI_PROBE_ONLY);
+ }
+
+ if (of_pci_parse_bus_range(np, &pci->cfg.bus_range))
+ pci->cfg.bus_range = (struct resource) {
+ .name = np->name,
+ .start = 0,
+ .end = 0xff,
+ .flags = IORESOURCE_BUS,
+ };
+
+ err = of_address_to_resource(np, 0, &pci->cfg.res);
+ if (err) {
+ dev_err(dev, "missing \"reg\" property\n");
+ return err;
+ }
+
+ pci->cfg.win = devm_kcalloc(dev, resource_size(&pci->cfg.bus_range),
+ sizeof(*pci->cfg.win), GFP_KERNEL);
+ if (!pci->cfg.win)
+ return -ENOMEM;
+
+ of_id = of_match_node(gen_pci_of_match, np);
+ pci->cfg.ops = of_id->data;
+ INIT_LIST_HEAD(&pci->host.windows);
+ INIT_LIST_HEAD(&pci->resources);
+
+ /* Limit the bus-range to fit within reg */
+ bus_max = pci->cfg.bus_range.start +
+ (resource_size(&pci->cfg.res) >> pci->cfg.ops->bus_shift) - 1;
+ pci->cfg.bus_range.end = min_t(resource_size_t, pci->cfg.bus_range.end,
+ bus_max);
+
+ /* Create and register resources from the ranges property */
+ res_valid = 0;
+ for_each_of_pci_range(&parser, &range) {
+ struct resource *parent, *res;
+ resource_size_t offset;
+ u32 restype = range.flags & IORESOURCE_TYPE_BITS;
+
+ res = devm_kmalloc(dev, sizeof(*res), GFP_KERNEL);
+ if (!res) {
+ err = -ENOMEM;
+ goto out_release_res;
+ }
+
+ switch (restype) {
+ case IORESOURCE_IO:
+ parent = &ioport_resource;
+ err = gen_pci_calc_io_offset(dev, &range, res, &offset);
+ break;
+ case IORESOURCE_MEM:
+ parent = &iomem_resource;
+ err = gen_pci_calc_mem_offset(dev, &range, res, &offset);
+ res_valid |= !(res->flags & IORESOURCE_PREFETCH || err);
+ break;
+ default:
+ err = -EINVAL;
+ continue;
+ }
+
+ if (err) {
+ dev_warn(dev,
+ "error %d: failed to add resource [type 0x%x, %lld bytes]\n",
+ err, restype, range.size);
+ continue;
+ }
+
+ err = request_resource(parent, res);
+ if (err)
+ goto out_release_res;
+
+ pci_add_resource_offset(&pci->resources, res, offset);
+ }
+
+ if (!res_valid) {
+ dev_err(dev, "non-prefetchable memory resource required\n");
+ err = -EINVAL;
+ goto out_release_res;
+ }
+
+ /* Map our Configuration Space windows */
+ err = -ENOMEM;
+ if (!devm_request_mem_region(dev, pci->cfg.res.start,
+ resource_size(&pci->cfg.res),
+ "Configuration Space"))
+ goto out_release_res;
+
+ bus_range = &pci->cfg.bus_range;
+ for (busn = bus_range->start; busn <= bus_range->end; ++busn) {
+ u32 idx = busn - bus_range->start;
+ u32 sz = 1 << pci->cfg.ops->bus_shift;
+
+ pci->cfg.win[idx] = devm_ioremap(dev,
+ pci->cfg.res.start + busn * sz,
+ sz);
+ if (!pci->cfg.win[idx])
+ goto out_release_res;
+ }
+
+ /* Register bus resource */
+ pci_add_resource(&pci->resources, bus_range);
+ pci_common_init_dev(dev, &hw);
+ return 0;
+
+out_release_res:
+ list_for_each_entry(win, &pci->resources, list)
+ release_resource(win->res);
+
+ pci_free_resource_list(&pci->resources);
+ return err;
+}
+
+static struct platform_driver gen_pci_driver = {
+ .driver = {
+ .name = "pci-host-generic",
+ .owner = THIS_MODULE,
+ .of_match_table = gen_pci_of_match,
+ },
+ .probe = gen_pci_probe,
+};
+module_platform_driver(gen_pci_driver);
+
+MODULE_DESCRIPTION("Generic PCI host driver");
+MODULE_AUTHOR("Will Deacon <will.deacon at arm.com>");
+MODULE_LICENSE("GPLv2");
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