[PATCH] pci: generic host: make it more generic

[Ming Lei <ming.lei@canonical.com>]

This patch converts the generic host controller driver
into a more generic one, and basically don't need
platform's pcibios support, and use DT based generic
APIs to parse resource and remap IO port.

This patch has been tested on both ARMv7 and ARMv8
VM, and in theroy it should support other ARCHs too.

With this patch, virtio PCI block, network and scsi devices
can work well on ARMv7 and ARMv8 VM.

QEMU needs below patches for runing the test:

- Rob Herring's "Add generic PCI host device" patches
	http://lists.gnu.org/archive/html/qemu-devel/2014-06/msg03482.html
	http://lists.gnu.org/archive/html/qemu-devel/2014-06/msg03483.html
- Alvise Rigo's "Add Generic PCI host device update"
	http://marc.info/?l=qemu-devel&m=140506329920172&w=2

For ARMv8, cpu model of "host" and "cortex-a57" is missed
in Alvise Rigo's patchset, otherwise ARM64 VM can't boot.

All these QEMU patches can be found in below tree:

	http://kernel.ubuntu.com/git?p=ming/qemu.git;a=shortlog;h=refs/heads/arm64-pci-test

Signed-off-by: Ming Lei <ming.lei@canonical.com>
---
 drivers/pci/host/Kconfig            |    2 +-
 drivers/pci/host/pci-host-generic.c |  196 +++++++++++------------------------
 2 files changed, 63 insertions(+), 135 deletions(-)

diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index 3dc25fa..885034d 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -50,7 +50,7 @@ config PCI_RCAR_GEN2_PCIE
 
 config PCI_HOST_GENERIC
 	bool "Generic PCI host controller"
-	depends on ARM && OF
+	depends on OF
 	help
 	  Say Y here if you want to support a simple generic PCI host
 	  controller, such as the one emulated by kvmtool.
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
index 3d2076f..00d0ca3 100644
--- a/drivers/pci/host/pci-host-generic.c
+++ b/drivers/pci/host/pci-host-generic.c
@@ -44,12 +44,14 @@ struct gen_pci {
 	struct list_head			resources;
 };
 
+/* fake sysdata for cheating ARCH's pcibios code */
+static char	gen_sysdata[256];
+
 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;
+	struct gen_pci *pci = dev_get_drvdata(bus->dev.parent->parent);
 	resource_size_t idx = bus->number - pci->cfg.bus_range.start;
 
 	return pci->cfg.win[idx] + ((devfn << 8) | where);
@@ -64,8 +66,7 @@ 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;
+	struct gen_pci *pci = dev_get_drvdata(bus->dev.parent->parent);
 	resource_size_t idx = bus->number - pci->cfg.bus_range.start;
 
 	return pci->cfg.win[idx] + ((devfn << 12) | where);
@@ -80,8 +81,7 @@ 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;
+	struct gen_pci *pci = dev_get_drvdata(bus->dev.parent->parent);
 
 	addr = pci->cfg.ops->map_bus(bus, devfn, where);
 
@@ -103,8 +103,7 @@ 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;
+	struct gen_pci *pci = dev_get_drvdata(bus->dev.parent->parent);
 
 	addr = pci->cfg.ops->map_bus(bus, devfn, where);
 
@@ -138,45 +137,6 @@ static const struct of_device_id gen_pci_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, gen_pci_of_match);
 
-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 void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
 {
 	struct pci_host_bridge_window *win;
@@ -187,72 +147,6 @@ static void gen_pci_release_of_pci_ranges(struct gen_pci *pci)
 	pci_free_resource_list(&pci->resources);
 }
 
-static int gen_pci_parse_request_of_pci_ranges(struct gen_pci *pci)
-{
-	struct of_pci_range range;
-	struct of_pci_range_parser parser;
-	int err, res_valid = 0;
-	struct device *dev = pci->host.dev.parent;
-	struct device_node *np = dev->of_node;
-
-	if (of_pci_range_parser_init(&parser, np)) {
-		dev_err(dev, "missing \"ranges\" property\n");
-		return -EINVAL;
-	}
-
-	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;
-	}
-
-	return 0;
-
-out_release_res:
-	gen_pci_release_of_pci_ranges(pci);
-	return err;
-}
-
 static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
 {
 	int err;
@@ -305,16 +199,33 @@ static int gen_pci_parse_map_cfg_windows(struct gen_pci *pci)
 			return -ENOMEM;
 	}
 
-	/* Register bus resource */
-	pci_add_resource(&pci->resources, bus_range);
 	return 0;
 }
 
-static int gen_pci_setup(int nr, struct pci_sys_data *sys)
+static int gen_pci_map_ranges(struct list_head *res,
+		resource_size_t io_base)
 {
-	struct gen_pci *pci = sys->private_data;
-	list_splice_init(&pci->resources, &sys->resources);
-	return 1;
+	struct pci_host_bridge_window *window;
+	int ret;
+
+	list_for_each_entry(window, res, list) {
+		struct resource *res = window->res;
+		u64 restype = resource_type(res);
+
+		switch (restype) {
+		case IORESOURCE_IO:
+			ret = pci_remap_iospace(res, io_base);
+			if (ret < 0)
+				return ret;
+			break;
+		case IORESOURCE_MEM:
+		case IORESOURCE_BUS:
+			break;
+		default:
+			return -EINVAL;
+		}
+	}
+	return 0;
 }
 
 static int gen_pci_probe(struct platform_device *pdev)
@@ -325,14 +236,11 @@ static int gen_pci_probe(struct platform_device *pdev)
 	const int *prop;
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
+	resource_size_t iobase = 0;
 	struct gen_pci *pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
-	struct hw_pci hw = {
-		.nr_controllers	= 1,
-		.private_data	= (void **)&pci,
-		.setup		= gen_pci_setup,
-		.map_irq	= of_irq_parse_and_map_pci,
-		.ops		= &gen_pci_ops,
-	};
+	struct pci_bus *bus;
+	struct pci_dev *pci_dev = NULL;
+	bool probe_only = false;
 
 	if (!pci)
 		return -ENOMEM;
@@ -346,9 +254,9 @@ static int gen_pci_probe(struct platform_device *pdev)
 	prop = of_get_property(of_chosen, "linux,pci-probe-only", NULL);
 	if (prop) {
 		if (*prop)
-			pci_add_flags(PCI_PROBE_ONLY);
+			probe_only = true;
 		else
-			pci_clear_flags(PCI_PROBE_ONLY);
+			probe_only = false;
 	}
 
 	of_id = of_match_node(gen_pci_of_match, np);
@@ -357,20 +265,40 @@ static int gen_pci_probe(struct platform_device *pdev)
 	INIT_LIST_HEAD(&pci->host.windows);
 	INIT_LIST_HEAD(&pci->resources);
 
-	/* Parse our PCI ranges and request their resources */
-	err = gen_pci_parse_request_of_pci_ranges(pci);
+	err = of_pci_get_host_bridge_resources(np, 0, 0xff,
+			&pci->resources, &iobase);
 	if (err)
 		return err;
 
 	/* Parse and map our Configuration Space windows */
 	err = gen_pci_parse_map_cfg_windows(pci);
-	if (err) {
-		gen_pci_release_of_pci_ranges(pci);
-		return err;
+	if (err)
+		goto fail;
+
+	err = gen_pci_map_ranges(&pci->resources, iobase);
+	if (err)
+		goto fail;
+
+	err = -ENOMEM;
+	platform_set_drvdata(pdev, pci);
+	bus = pci_scan_root_bus(dev, 0, &gen_pci_ops, gen_sysdata,
+				&pci->resources);
+	if (!bus)
+		goto fail;
+
+	for_each_pci_dev(pci_dev)
+		pci_dev->irq = of_irq_parse_and_map_pci(pci_dev, 0, 0);
+
+	if (!probe_only) {
+		pci_bus_size_bridges(bus);
+		pci_bus_assign_resources(bus);
+		pci_bus_add_devices(bus);
 	}
 
-	pci_common_init_dev(dev, &hw);
 	return 0;
+ fail:
+	gen_pci_release_of_pci_ranges(pci);
+	return err;
 }
 
 static struct platform_driver gen_pci_driver = {
-- 
1.7.9.5