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PCI: tegra: Refactor configuration space mapping code 

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@nvidia.com>
[treding@nvidia.com: various cleanups, update commit message]
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
This commit is contained in:
Vidya Sagar 2017-12-20 21:36:07 +01:00 committed by Lorenzo Pieralisi
parent 1291a0d504
commit 1fd92928ba
1 changed files with 30 additions and 118 deletions
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148
drivers/pci/host/pci-tegra.c
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@ -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)
static unsigned int tegra_pcie_conf_offset(u8 bus, unsigned int devfn,
unsigned 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)
{
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;
}
@ -2347,7 +2260,6 @@ 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;