[PATCH v3 2/2] pci, pci-thunder-pem: Add PCIe host driver for ThunderX processors.

David Daney
2016-01-08T23:59:13Z

Some Cavium ThunderX processors require quirky access methods for the
config space of the PCIe bridge. Add a driver to provide these config
space accessor functions. The pci-host-common code is used to
configure the PCI machinery.

Signed-off-by: David Daney <david.daney@cavium.com>
---
.../devicetree/bindings/pci/pci-thunder-pem.txt | 43 ++++
MAINTAINERS | 8 +
drivers/pci/host/Kconfig | 7 +
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pci-thunder-pem.c | 283 +++++++++++++++++++++
5 files changed, 342 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pci/pci-thunder-pem.txt
create mode 100644 drivers/pci/host/pci-thunder-pem.c

diff --git a/Documentation/devicetree/bindings/pci/pci-thunder-pem.txt b/Documentation/devicetree/bindings/pci/pci-thunder-pem.txt
new file mode 100644
index 0000000..f131fae
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/pci-thunder-pem.txt
@@ -0,0 +1,43 @@
+* ThunderX PEM PCIe host controller
+
+Firmware-initialized PCI host controller found on some Cavium
+ThunderX processors.
+
+The properties and their meanings are identical to those described in
+host-generic-pci.txt except as listed below.
+
+Properties of the host controller node that differ from
+host-generic-pci.txt:
+
+- compatible : Must be "cavium,pci-host-thunder-pem"
+
+- reg : Two entries: First the configuration space for down
+ stream devices base address and size, as accessed
+ from the parent bus. Second, the register bank of
+ the PEM device PCIe bridge.
+
+Example:
+
+ pci@87e0,c2000000 {
+ compatible = "cavium,pci-host-thunder-pem";
+ device_type = "pci";
+ msi-parent = <&its>;
+ msi-map = <0 &its 0x10000 0x10000>;
+ bus-range = <0x8f 0xc7>;
+ #size-cells = <2>;
+ #address-cells = <3>;
+
+ reg = <0x8880 0x8f000000 0x0 0x39000000>, /* Configuration space */
+ <0x87e0 0xc2000000 0x0 0x00010000>; /* PEM space */
+ ranges = <0x01000000 0x00 0x00020000 0x88b0 0x00020000 0x00 0x00010000>, /* I/O */
+ <0x03000000 0x00 0x10000000 0x8890 0x10000000 0x0f 0xf0000000>, /* mem64 */
+ <0x43000000 0x10 0x00000000 0x88a0 0x00000000 0x10 0x00000000>, /* mem64-pref */
+ <0x03000000 0x87e0 0xc2f00000 0x87e0 0xc2000000 0x00 0x00100000>; /* mem64 PEM BAR4 */
+
+ #interrupt-cells = <1>;
+ interrupt-map-mask = <0 0 0 7>;
+ interrupt-map = <0 0 0 1 &gic0 0 0 0 24 4>, /* INTA */
+ <0 0 0 2 &gic0 0 0 0 25 4>, /* INTB */
+ <0 0 0 3 &gic0 0 0 0 26 4>, /* INTC */
+ <0 0 0 4 &gic0 0 0 0 27 4>; /* INTD */
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index a3fc8b4..24a04cc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8249,6 +8249,14 @@ S: Maintained
F: Documentation/devicetree/bindings/pci/hisilicon-pcie.txt
F: drivers/pci/host/pcie-hisi.c

+PCIE DRIVER FOR CAVIUM THUNDERX
+M: David Daney <david.daney@cavium.com>
+L: linux-pci@vger.kernel.org
+L: linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+S: Supported
+F: Documentation/devicetree/bindings/pci/pci-thunder-pem.txt
+F: drivers/pci/host/pci-thunder-pem.c
+
PCMCIA SUBSYSTEM
P: Linux PCMCIA Team
L: linux-pcmcia@lists.infradead.org
diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index f171459..ad32f251 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -176,4 +176,11 @@ config PCI_HISI
help
Say Y here if you want PCIe controller support on HiSilicon HIP05 SoC

+config PCI_HOST_THUNDER_PEM
+ bool "Cavium Thunder PCIe controller to off-chip devices"
+ depends on OF && ARM64
+ select PCI_HOST_COMMON
+ help
+ Say Y here if you want PCIe support for CN88XX Cavium Thunder SoCs.
+
endmenu
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index ba2c51f..a068d10 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -21,3 +21,4 @@ obj-$(CONFIG_PCIE_IPROC_BCMA) += pcie-iproc-bcma.o
obj-$(CONFIG_PCIE_ALTERA) += pcie-altera.o
obj-$(CONFIG_PCIE_ALTERA_MSI) += pcie-altera-msi.o
obj-$(CONFIG_PCI_HISI) += pcie-hisi.o
+obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.o
diff --git a/drivers/pci/host/pci-thunder-pem.c b/drivers/pci/host/pci-thunder-pem.c
new file mode 100644
index 0000000..43fa6f5
--- /dev/null
+++ b/drivers/pci/host/pci-thunder-pem.c
@@ -0,0 +1,283 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright (C) 2015 Cavium, Inc.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+#include <linux/platform_device.h>
+
+#include "pci-host-common.h"
+
+#define PEM_CFG_WR 0x28
+#define PEM_CFG_RD 0x30
+
+struct thunder_pem_pci {
+ struct gen_pci gen_pci;
+ u32 ea_entry[3];
+ void __iomem *pem_reg_base;
+};
+
+static int thunder_pem_config_read(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 *val)
+{
+ int r;
+ struct thunder_pem_pci *pem_pci;
+ struct gen_pci *pci = bus->sysdata;
+
+ pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci);
+
+ /*
+ * The first device on the bus in the PEM PCIe bridge.
+ * Special case its config access.
+ */
+ if (bus->number == pci->cfg.bus_range->start) {
+ u64 read_val;
+
+ if (devfn != 0 || where >= 2048) {
+ *val = ~0;
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ }
+
+ /*
+ * 32-bit accesses only. Write the address to the low
+ * order bits of PEM_CFG_RD, then trigger the read by
+ * reading back. The config data lands in the upper
+ * 32-bits of PEM_CFG_RD.
+ */
+ read_val = where & ~3ull;
+ writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val >>= 32;
+
+ /*
+ * The config space contains some garbage, fix it up.
+ * Also synthesize an EA capability for the BAR used
+ * by MSI-X.
+ */
+ switch (where & ~3u) {
+ case 0x40:
+ read_val &= 0xffff00ff;
+ read_val |= 0x00007000; /* Skip MSI CAP */
+ break;
+ case 0x70: /* Express Cap */
+ /* PME interrupt on vector 2*/
+ read_val |= (2u << 25);
+ break;
+ case 0xb0: /* MSI-X Cap */
+ /* TableSize=4, Next Cap is EA */
+ read_val &= 0xc00000ff;
+ read_val |= 0x0003bc00;
+ break;
+ case 0xb4:
+ /* Table offset=0, BIR=0 */
+ read_val = 0x00000000;
+ break;
+ case 0xb8:
+ /* BPA offset=0xf0000, BIR=0 */
+ read_val = 0x000f0000;
+ break;
+ case 0xbc:
+ /* EA, 1 entry, no next Cap */
+ read_val = 0x00010014;
+ break;
+ case 0xc0:
+ /* DW2 for type-1 */
+ read_val = 0x00000000;
+ break;
+ case 0xc4:
+ /* Entry BEI=0, PP=0x00, SP=0xff, ES=3 */
+ read_val = 0x80ff0003;
+ break;
+ case 0xc8:
+ read_val = pem_pci->ea_entry[0];
+ break;
+ case 0xcc:
+ read_val = pem_pci->ea_entry[1];
+ break;
+ case 0xd0:
+ read_val = pem_pci->ea_entry[2];
+ break;
+ default:
+ break;
+ }
+ read_val >>= (8 * (where & 3));
+ switch (size) {
+ case 1:
+ read_val &= 0xff;
+ break;
+ case 2:
+ read_val &= 0xffff;
+ break;
+ default:
+ break;
+ }
+ *val = read_val;
+ return PCIBIOS_SUCCESSFUL;
+ }
+ if (bus->number < pci->cfg.bus_range->start ||
+ bus->number > pci->cfg.bus_range->end)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ r = pci_generic_config_read(bus, devfn, where, size, val);
+ return r;
+}
+
+static int thunder_pem_config_write(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, u32 val)
+{
+ struct gen_pci *pci = bus->sysdata;
+ struct thunder_pem_pci *pem_pci;
+
+ pem_pci = container_of(pci, struct thunder_pem_pci, gen_pci);
+
+ /*
+ * The first device on the bus in the PEM PCIe bridge.
+ * Special case its config access.
+ */
+ if (bus->number == pci->cfg.bus_range->start) {
+ u64 write_val, read_val;
+
+ if (devfn != 0 || where >= 2048)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ /*
+ * 32-bit accesses only. If the write is for a size
+ * smaller than 32-bits, we must first read the 32-bit
+ * value and merge in the desired bits and then write
+ * the whole 32-bits back out.
+ */
+ switch (size) {
+ case 1:
+ read_val = where & ~3ull;
+ writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val >>= 32;
+ read_val &= ~(0xff << (8 * (where & 3)));
+ val = (val & 0xff) << (8 * (where & 3));
+ val |= (u32)read_val;
+ break;
+ case 2:
+ read_val = where & ~3ull;
+ writeq(read_val, pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val = readq(pem_pci->pem_reg_base + PEM_CFG_RD);
+ read_val >>= 32;
+ read_val &= ~(0xffff << (8 * (where & 3)));
+ val = (val & 0xffff) << (8 * (where & 3));
+ val |= (u32)read_val;
+ break;
+ default:
+ break;
+
+ }
+ /*
+ * Low order bits are the config address, the high
+ * order 32 bits are the data to be written.
+ */
+ write_val = where & ~3ull;
+ write_val |= (((u64)val) << 32);
+ writeq(write_val, pem_pci->pem_reg_base + PEM_CFG_WR);
+ return PCIBIOS_SUCCESSFUL;
+ }
+ if (bus->number < pci->cfg.bus_range->start ||
+ bus->number > pci->cfg.bus_range->end)
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ return pci_generic_config_write(bus, devfn, where, size, val);
+}
+
+static void __iomem *map_cfg_bus_thunder_pem(struct pci_bus *bus,
+ unsigned int devfn,
+ int where)
+{
+ struct gen_pci *pci = bus->sysdata;
+ resource_size_t idx = bus->number - pci->cfg.bus_range->start;
+
+ return pci->cfg.win[idx] + ((devfn << 16) | where);
+}
+
+static struct gen_pci_cfg_bus_ops thunder_pem_bus_ops = {
+ .bus_shift = 24,
+ .ops = {
+ .map_bus = map_cfg_bus_thunder_pem,
+ .read = thunder_pem_config_read,
+ .write = thunder_pem_config_write,
+ }
+};
+
+static const struct of_device_id thunder_pem_of_match[] = {
+ { .compatible = "cavium,pci-host-thunder-pem",
+ .data = &thunder_pem_bus_ops },
+
+ { },
+};
+MODULE_DEVICE_TABLE(of, thunder_pem_of_match);
+
+static int thunder_pem_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ const struct of_device_id *of_id;
+ resource_size_t bar4_start;
+ struct resource *res_pem;
+ struct thunder_pem_pci *pem_pci;
+
+ pem_pci = devm_kzalloc(dev, sizeof(*pem_pci), GFP_KERNEL);
+ if (!pem_pci)
+ return -ENOMEM;
+
+ of_id = of_match_node(thunder_pem_of_match, dev->of_node);
+ pem_pci->gen_pci.cfg.ops = (struct gen_pci_cfg_bus_ops *)of_id->data;
+
+ /*
+ * The second register range is the PEM bridge to the PCIe
+ * bus. It has a different config access method than those
+ * devices behind the bridge.
+ */
+ res_pem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!res_pem) {
+ dev_err(dev, "missing \"reg[1]\"property\n");
+ return -EINVAL;
+ }
+
+ pem_pci->pem_reg_base = devm_ioremap(dev, res_pem->start, 0x10000);
+ if (!pem_pci->pem_reg_base)
+ return -ENOMEM;
+
+ /*
+ * The MSI-X BAR for the PEM and AER interrupts is located at
+ * a fixed offset from the PEM register base. Generate a
+ * fragment of the synthesized Enhanced Allocation capability
+ * structure here for the BAR.
+ */
+ bar4_start = res_pem->start + 0xf00000;
+ pem_pci->ea_entry[0] = (u32)bar4_start | 2;
+ pem_pci->ea_entry[1] = (u32)(res_pem->end - bar4_start) & ~3u;
+ pem_pci->ea_entry[2] = (u32)(bar4_start >> 32);
+
+ return pci_host_common_probe(pdev, &pem_pci->gen_pci);
+}
+
+static struct platform_driver thunder_pem_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = thunder_pem_of_match,
+ },
+ .probe = thunder_pem_probe,
+};
+module_platform_driver(thunder_pem_driver);
+
+MODULE_DESCRIPTION("Thunder PEM PCIe host driver");
+MODULE_LICENSE("GPL v2");
--
1.8.3.1