This patch adds a driver for the Xilinx AXI bridge for PCI express, an IP block which can be used on some generations of Xilinx FPGAs. This is mostly a case of implementing PCIe ECAM specification, but with some quirks about what devices are valid to access.
Signed-off-by: Paul Burton paul.burton@imgtec.com Reviewed-by: Simon Glass sjg@chromium.org
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Changes in v2: - Clean up error returns & documentation
drivers/pci/Kconfig | 7 ++ drivers/pci/Makefile | 1 + drivers/pci/pcie_xilinx.c | 219 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 227 insertions(+) create mode 100644 drivers/pci/pcie_xilinx.c
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 26aa2b0..1f9ea66 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -38,4 +38,11 @@ config PCI_TEGRA with a total of 5 lanes. Some boards require this for Ethernet support to work (e.g. beaver, jetson-tk1).
+config PCI_XILINX + bool "Xilinx AXI Bridge for PCI Express" + depends on DM_PCI + help + Enable support for the Xilinx AXI bridge for PCI express, an IP block + which can be used on some generations of Xilinx FPGAs. + endmenu diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index f8be9bf..9583e91 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -31,3 +31,4 @@ obj-$(CONFIG_PCI_TEGRA) += pci_tegra.o obj-$(CONFIG_TSI108_PCI) += tsi108_pci.o obj-$(CONFIG_WINBOND_83C553) += w83c553f.o obj-$(CONFIG_PCIE_LAYERSCAPE) += pcie_layerscape.o +obj-$(CONFIG_PCI_XILINX) += pcie_xilinx.o diff --git a/drivers/pci/pcie_xilinx.c b/drivers/pci/pcie_xilinx.c new file mode 100644 index 0000000..9fe02be --- /dev/null +++ b/drivers/pci/pcie_xilinx.c @@ -0,0 +1,219 @@ +/* + * Xilinx AXI Bridge for PCI Express Driver + * + * Copyright (C) 2016 Imagination Technologies + * + * SPDX-License-Identifier: GPL-2.0 + */ + +#include <common.h> +#include <dm.h> +#include <pci.h> + +#include <asm/io.h> + +/** + * struct xilinx_pcie - Xilinx PCIe controller state + * @hose: The parent classes PCI controller state + * @cfg_base: The base address of memory mapped configuration space + */ +struct xilinx_pcie { + struct pci_controller hose; + void *cfg_base; +}; + +/* Register definitions */ +#define XILINX_PCIE_REG_PSCR 0x144 +#define XILINX_PCIE_REG_PSCR_LNKUP BIT(11) + +/** + * pcie_xilinx_link_up() - Check whether the PCIe link is up + * @pcie: Pointer to the PCI controller state + * + * Checks whether the PCIe link for the given device is up or down. + * + * Return: true if the link is up, else false + */ +static bool pcie_xilinx_link_up(struct xilinx_pcie *pcie) +{ + uint32_t pscr = __raw_readl(pcie->cfg_base + XILINX_PCIE_REG_PSCR); + + return pscr & XILINX_PCIE_REG_PSCR_LNKUP; +} + +/** + * pcie_xilinx_config_address() - Calculate the address of a config access + * @pcie: Pointer to the PCI controller state + * @bdf: Identifies the PCIe device to access + * @offset: The offset into the device's configuration space + * @paddress: Pointer to the pointer to write the calculates address to + * + * Calculates the address that should be accessed to perform a PCIe + * configuration space access for a given device identified by the PCIe + * controller device @pcie and the bus, device & function numbers in @bdf. If + * access to the device is not valid then the function will return an error + * code. Otherwise the address to access will be written to the pointer pointed + * to by @paddress. + * + * Return: 0 on success, else -ENODEV + */ +static int pcie_xilinx_config_address(struct xilinx_pcie *pcie, pci_dev_t bdf, + uint offset, void **paddress) +{ + unsigned int bus = PCI_BUS(bdf); + unsigned int dev = PCI_DEV(bdf); + unsigned int func = PCI_FUNC(bdf); + void *addr; + + if ((bus > 0) && !pcie_xilinx_link_up(pcie)) + return -ENODEV; + + /* + * Busses 0 (host-PCIe bridge) & 1 (its immediate child) are + * limited to a single device each. + */ + if ((bus < 2) && (dev > 0)) + return -ENODEV; + + addr = pcie->cfg_base; + addr += bus << 20; + addr += dev << 15; + addr += func << 12; + addr += offset; + *paddress = addr; + + return 0; +} + +/** + * pcie_xilinx_read_config() - Read from configuration space + * @pcie: Pointer to the PCI controller state + * @bdf: Identifies the PCIe device to access + * @offset: The offset into the device's configuration space + * @valuep: A pointer at which to store the read value + * @size: Indicates the size of access to perform + * + * Read a value of size @size from offset @offset within the configuration + * space of the device identified by the bus, device & function numbers in @bdf + * on the PCI bus @bus. + * + * Return: 0 on success, else -ENODEV or -EINVAL + */ +static int pcie_xilinx_read_config(struct udevice *bus, pci_dev_t bdf, + uint offset, ulong *valuep, + enum pci_size_t size) +{ + struct xilinx_pcie *pcie = dev_get_priv(bus); + void *address; + int err; + + err = pcie_xilinx_config_address(pcie, bdf, offset, &address); + if (err < 0) { + *valuep = pci_get_ff(size); + return 0; + } + + switch (size) { + case PCI_SIZE_8: + *valuep = __raw_readb(address); + return 0; + case PCI_SIZE_16: + *valuep = __raw_readw(address); + return 0; + case PCI_SIZE_32: + *valuep = __raw_readl(address); + return 0; + default: + return -EINVAL; + } +} + +/** + * pcie_xilinx_write_config() - Write to configuration space + * @pcie: Pointer to the PCI controller state + * @bdf: Identifies the PCIe device to access + * @offset: The offset into the device's configuration space + * @value: The value to write + * @size: Indicates the size of access to perform + * + * Write the value @value of size @size from offset @offset within the + * configuration space of the device identified by the bus, device & function + * numbers in @bdf on the PCI bus @bus. + * + * Return: 0 on success, else -ENODEV or -EINVAL + */ +static int pcie_xilinx_write_config(struct udevice *bus, pci_dev_t bdf, + uint offset, ulong value, + enum pci_size_t size) +{ + struct xilinx_pcie *pcie = dev_get_priv(bus); + void *address; + int err; + + err = pcie_xilinx_config_address(pcie, bdf, offset, &address); + if (err < 0) + return 0; + + switch (size) { + case PCI_SIZE_8: + __raw_writeb(value, address); + return 0; + case PCI_SIZE_16: + __raw_writew(value, address); + return 0; + case PCI_SIZE_32: + __raw_writel(value, address); + return 0; + default: + return -EINVAL; + } +} + +/** + * pcie_xilinx_ofdata_to_platdata() - Translate from DT to device state + * @dev: A pointer to the device being operated on + * + * Translate relevant data from the device tree pertaining to device @dev into + * state that the driver will later make use of. This state is stored in the + * device's private data structure. + * + * Return: 0 on success, else -EINVAL + */ +static int pcie_xilinx_ofdata_to_platdata(struct udevice *dev) +{ + struct xilinx_pcie *pcie = dev_get_priv(dev); + struct fdt_resource reg_res; + DECLARE_GLOBAL_DATA_PTR; + int err; + + err = fdt_get_resource(gd->fdt_blob, dev->of_offset, "reg", + 0, ®_res); + if (err < 0) { + error(""reg" resource not found\n"); + return err; + } + + pcie->cfg_base = ioremap_nocache(reg_res.start, + fdt_resource_size(®_res)); + + return 0; +} + +static const struct dm_pci_ops pcie_xilinx_ops = { + .read_config = pcie_xilinx_read_config, + .write_config = pcie_xilinx_write_config, +}; + +static const struct udevice_id pcie_xilinx_ids[] = { + { .compatible = "xlnx,axi-pcie-host-1.00.a" }, + { } +}; + +U_BOOT_DRIVER(pcie_xilinx) = { + .name = "pcie_xilinx", + .id = UCLASS_PCI, + .of_match = pcie_xilinx_ids, + .ops = &pcie_xilinx_ops, + .ofdata_to_platdata = pcie_xilinx_ofdata_to_platdata, + .priv_auto_alloc_size = sizeof(struct xilinx_pcie), +};