[U-Boot] [PATCH v2 03/10] pci: xilinx: Add a driver for Xilinx AXI to PCIe bridge
Paul Burton
paul.burton at imgtec.com
Wed Jul 27 16:26:44 CEST 2016
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 at imgtec.com>
Reviewed-by: Simon Glass <sjg at chromium.org>
---
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),
+};
--
2.9.0
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