From: Vidya Sagar <vidyas@xxxxxxxxxx>
Use only 4 KiB space from the available 1 GiB PCIe aperture to access
endpoint configuration space by dynamically moving the AFI_FPCI_BAR base
address. This frees more space for mapping endpoint device BARs on some
Tegra platforms.
The ->add_bus() and ->remove_bus() callbacks are now no longer needed,
so they can be removed.
Signed-off-by: Vidya Sagar <vidyas@xxxxxxxxxx>
[treding@xxxxxxxxxx: various cleanups, update commit message]
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/pci/host/pci-tegra.c | 148 +++++++++----------------------------------
1 file changed, 30 insertions(+), 118 deletions(-)
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index f2214ca1ad17..56434aa44b60 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -269,11 +269,10 @@ struct tegra_pcie {
void __iomem *pads;
void __iomem *afi;
+ void __iomem *cfg;
int irq;
- struct list_head buses;
- struct resource *cs;
-
+ struct resource cs;
struct resource io;
struct resource pio;
struct resource mem;
@@ -322,7 +321,6 @@ struct tegra_pcie_port {
};
struct tegra_pcie_bus {
- struct vm_struct *area;
struct list_head list;
unsigned int nr;
};
@@ -362,100 +360,19 @@ static inline u32 pads_readl(struct tegra_pcie *pcie, unsigned long offset)
*
* Mapping the whole extended configuration space would require 256 MiB of
* virtual address space, only a small part of which will actually be used.
- * To work around this, a 1 MiB of virtual addresses are allocated per bus
- * when the bus is first accessed. When the physical range is mapped, the
- * the bus number bits are hidden so that the extended register number bits
- * appear as bits [19:16]. Therefore the virtual mapping looks like this:
- *
- * [19:16] extended register number
- * [15:11] device number
- * [10: 8] function number
- * [ 7: 0] register number
*
- * This is achieved by stitching together 16 chunks of 64 KiB of physical
- * address space via the MMU.
+ * To work around this, a 4 KiB region is used to generate the required
+ * configuration transaction with relevant B:D:F and register offset values.
+ * This is achieved by dynamically programming base address and size of
+ * AFI_AXI_BAR used for end point config space mapping to make sure that the
+ * address (access to which generates correct config transaction) falls in
+ * this 4 KiB region.
*/
-static unsigned long tegra_pcie_conf_offset(unsigned int devfn, int where)
-{
- return ((where & 0xf00) << 8) | (PCI_SLOT(devfn) << 11) |
- (PCI_FUNC(devfn) << 8) | (where & 0xfc);
-}
-
-static struct tegra_pcie_bus *tegra_pcie_bus_alloc(struct tegra_pcie *pcie,
- unsigned int busnr)
+static unsigned int tegra_pcie_conf_offset(u8 bus, unsigned int devfn,
+ unsigned int where)
{
- struct device *dev = pcie->dev;
- pgprot_t prot = pgprot_noncached(PAGE_KERNEL);
- phys_addr_t cs = pcie->cs->start;
- struct tegra_pcie_bus *bus;
- unsigned int i;
- int err;
-
- bus = kzalloc(sizeof(*bus), GFP_KERNEL);
- if (!bus)
- return ERR_PTR(-ENOMEM);
-
- INIT_LIST_HEAD(&bus->list);
- bus->nr = busnr;
-
- /* allocate 1 MiB of virtual addresses */
- bus->area = get_vm_area(SZ_1M, VM_IOREMAP);
- if (!bus->area) {
- err = -ENOMEM;
- goto free;
- }
-
- /* map each of the 16 chunks of 64 KiB each */
- for (i = 0; i < 16; i++) {
- unsigned long virt = (unsigned long)bus->area->addr +
- i * SZ_64K;
- phys_addr_t phys = cs + i * SZ_16M + busnr * SZ_64K;
-
- err = ioremap_page_range(virt, virt + SZ_64K, phys, prot);
- if (err < 0) {
- dev_err(dev, "ioremap_page_range() failed: %d\n", err);
- goto unmap;
- }
- }
-
- return bus;
-
-unmap:
- vunmap(bus->area->addr);
-free:
- kfree(bus);
- return ERR_PTR(err);
-}
-
-static int tegra_pcie_add_bus(struct pci_bus *bus)
-{
- struct pci_host_bridge *host = pci_find_host_bridge(bus);
- struct tegra_pcie *pcie = pci_host_bridge_priv(host);
- struct tegra_pcie_bus *b;
-
- b = tegra_pcie_bus_alloc(pcie, bus->number);
- if (IS_ERR(b))
- return PTR_ERR(b);
-
- list_add_tail(&b->list, &pcie->buses);
-
- return 0;
-}
-
-static void tegra_pcie_remove_bus(struct pci_bus *child)
-{
- struct pci_host_bridge *host = pci_find_host_bridge(child);
- struct tegra_pcie *pcie = pci_host_bridge_priv(host);
- struct tegra_pcie_bus *bus, *tmp;
-
- list_for_each_entry_safe(bus, tmp, &pcie->buses, list) {
- if (bus->nr == child->number) {
- vunmap(bus->area->addr);
- list_del(&bus->list);
- kfree(bus);
- break;
- }
- }
+ return ((where & 0xf00) << 16) | (bus << 16) | (PCI_SLOT(devfn) << 11) |
+ (PCI_FUNC(devfn) << 8) | (where & 0xff);
}
static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus,
@@ -464,7 +381,6 @@ static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus,
{
struct pci_host_bridge *host = pci_find_host_bridge(bus);
struct tegra_pcie *pcie = pci_host_bridge_priv(host);
- struct device *dev = pcie->dev;
void __iomem *addr = NULL;
if (bus->number == 0) {
@@ -478,19 +394,17 @@ static void __iomem *tegra_pcie_map_bus(struct pci_bus *bus,
}
}
} else {
- struct tegra_pcie_bus *b;
+ unsigned int offset;
+ u32 base;
- list_for_each_entry(b, &pcie->buses, list)
- if (b->nr == bus->number)
- addr = (void __iomem *)b->area->addr;
+ offset = tegra_pcie_conf_offset(bus->number, devfn, where);
- if (!addr) {
- dev_err(dev, "failed to map cfg. space for bus %u\n",
- bus->number);
- return NULL;
- }
+ /* move 4 KiB window to offset within the FPCI region */
+ base = 0xfe100000 + ((offset & ~(SZ_4K - 1)) >> 8);
+ afi_writel(pcie, base, AFI_FPCI_BAR0);
- addr += tegra_pcie_conf_offset(devfn, where);
+ /* move to correct offset within the 4 KiB page */
+ addr = pcie->cfg + (offset & (SZ_4K - 1));
}
return addr;
@@ -517,8 +431,6 @@ static int tegra_pcie_config_write(struct pci_bus *bus, unsigned int devfn,
}
static struct pci_ops tegra_pcie_ops = {
- .add_bus = tegra_pcie_add_bus,
- .remove_bus = tegra_pcie_remove_bus,
.map_bus = tegra_pcie_map_bus,
.read = tegra_pcie_config_read,
.write = tegra_pcie_config_write,
@@ -743,12 +655,9 @@ static void tegra_pcie_setup_translations(struct tegra_pcie *pcie)
u32 fpci_bar, size, axi_address;
/* Bar 0: type 1 extended configuration space */
- fpci_bar = 0xfe100000;
- size = resource_size(pcie->cs);
- axi_address = pcie->cs->start;
- afi_writel(pcie, axi_address, AFI_AXI_BAR0_START);
+ size = resource_size(&pcie->cs);
+ afi_writel(pcie, pcie->cs.start, AFI_AXI_BAR0_START);
afi_writel(pcie, size >> 12, AFI_AXI_BAR0_SZ);
- afi_writel(pcie, fpci_bar, AFI_FPCI_BAR0);
/* Bar 1: downstream IO bar */
fpci_bar = 0xfdfc0000;
@@ -1353,10 +1262,14 @@ static int tegra_pcie_get_resources(struct tegra_pcie *pcie)
goto poweroff;
}
- pcie->cs = devm_request_mem_region(dev, res->start,
- resource_size(res), res->name);
- if (!pcie->cs) {
- err = -EADDRNOTAVAIL;
+ pcie->cs = *res;
+
+ /* constrain configuration space to 4 KiB */
+ pcie->cs.end = pcie->cs.start + SZ_4K - 1;
+
+ pcie->cfg = devm_ioremap_resource(dev, &pcie->cs);
+ if (IS_ERR(pcie->cfg)) {
+ err = PTR_ERR(pcie->cfg);
goto poweroff;
}
@@ -2376,7 +2289,6 @@ static int tegra_pcie_probe(struct platform_device *pdev)
pcie = pci_host_bridge_priv(host);
pcie->soc = of_device_get_match_data(dev);
- INIT_LIST_HEAD(&pcie->buses);
INIT_LIST_HEAD(&pcie->ports);
pcie->dev = dev;
--
2.15.1
--
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