[PATCH v7 4/4] PCI: Generic Configuration Access Mechanism support
Will Deacon
will.deacon at arm.com
Fri May 23 09:51:55 PDT 2014
From: Srikanth Thokala <sthokal at xilinx.com>
This patch adds support for a generic CAM and ECAM configuration
space accesses.
Signed-off-by: Srikanth Thokala <sthokal at xilinx.com>
Signed-off-by: Will Deacon <will.deacon at arm.com>
---
drivers/pci/Makefile | 2 +-
drivers/pci/pci-cfg.c | 162 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/pci.h | 34 +++++++++++
3 files changed, 197 insertions(+), 1 deletion(-)
create mode 100644 drivers/pci/pci-cfg.c
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index e04fe2d9df3b..37cfc3356e84 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -4,7 +4,7 @@
obj-y += access.o bus.o probe.o host-bridge.o remove.o pci.o \
pci-driver.o search.o pci-sysfs.o rom.o setup-res.o \
- irq.o vpd.o setup-bus.o vc.o
+ irq.o vpd.o setup-bus.o vc.o pci-cfg.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_SYSFS) += slot.o
diff --git a/drivers/pci/pci-cfg.c b/drivers/pci/pci-cfg.c
new file mode 100644
index 000000000000..2b15fe4c3c20
--- /dev/null
+++ b/drivers/pci/pci-cfg.c
@@ -0,0 +1,162 @@
+/*
+ * PCI generic configuration access mechanism
+ *
+ * Copyright (C) 2014 ARM Limited
+ * Copyright (c) 2014 Xilinx, Inc.
+ *
+ * Author: Will Deacon <will.deacon at arm.com>
+ *
+ * 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.
+ */
+
+#include <linux/of_pci.h>
+
+/* CAM definitions */
+#define PCI_CFG_CAM_BUS_NUM 16
+#define PCI_CFG_CAM_DEV_NUM 8
+
+/* ECAM definitions */
+#define PCI_CFG_ECAM_BUS_NUM 20
+#define PCI_CFG_ECAM_DEV_NUM 12
+
+/* Invalid device/function value */
+#define PCI_CFG_INVALID_DEVFN 0xFFFFFFFF
+
+/**
+ * pci_cfg_map_bus_cam - Get the CAM based configuration space address
+ * @bus: PCI Bus pointer
+ * @devfn: Device/Function
+ * @where: Offset from base
+ *
+ * Return: Configuration Space address
+ */
+static void __iomem *pci_cfg_map_bus_cam(struct pci_bus *bus,
+ unsigned int devfn,
+ int where)
+{
+ struct pci_sys_data *sys = bus->sysdata;
+ struct pci_cfg_windows *cfg = sys->private_data;
+ resource_size_t idx = bus->number - cfg->bus_range.start;
+
+ return cfg->win[idx] + ((devfn << PCI_CFG_CAM_DEV_NUM) | where);
+}
+
+/**
+ * pci_cfg_map_bus_ecam - Get the ECAM based configuration space address
+ * @bus: PCI bus pointer
+ * @devfn: Device/Function
+ * @where: Offset from base
+ *
+ * Return: Configuration space address
+ */
+static void __iomem *pci_cfg_map_bus_ecam(struct pci_bus *bus,
+ unsigned int devfn,
+ int where)
+{
+ struct pci_sys_data *sys = bus->sysdata;
+ struct pci_cfg_windows *cfg = sys->private_data;
+ resource_size_t idx = bus->number - cfg->bus_range.start;
+
+ return cfg->win[idx] + ((devfn << PCI_CFG_ECAM_DEV_NUM) | where);
+}
+
+/**
+ * pci_cfg_read - Read configuration space
+ * @bus: PCI bus pointer
+ * @devfn: Device/function
+ * @where: Offset from base
+ * @size: Byte/word/dword
+ * @val: Value to be read
+ *
+ * Return: PCIBIOS_SUCCESSFUL on success
+ * PCIBIOS_DEVICE_NOT_FOUND on failure
+ */
+static int pci_cfg_read(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, unsigned int *val)
+{
+ void __iomem *addr;
+ struct pci_sys_data *sys = bus->sysdata;
+ struct pci_cfg_windows *cfg = sys->private_data;
+
+ if (cfg->ops->is_valid_cfg_access) {
+ if (!cfg->ops->is_valid_cfg_access(bus, devfn)) {
+ *val = PCI_CFG_INVALID_DEVFN;
+ return PCIBIOS_DEVICE_NOT_FOUND;
+ }
+ }
+
+ addr = cfg->ops->map_bus(bus, devfn, where);
+
+ switch (size) {
+ case 1:
+ *val = readb(addr);
+ break;
+ case 2:
+ *val = readw(addr);
+ break;
+ default:
+ *val = readl(addr);
+ }
+
+ return PCIBIOS_SUCCESSFUL;
+}
+
+/**
+ * pci_cfg_write - Write configuration space
+ * @bus: PCI bus pointer
+ * @devfn: Device/function
+ * @where: Offset from base
+ * @size: Byte/word/dword
+ * @val: Value to write
+ *
+ * Return: PCIBIOS_SUCCESSFUL on success
+ * PCIBIOS_DEVICE_NOT_FOUND on failure
+ */
+static int pci_cfg_write(struct pci_bus *bus, unsigned int devfn,
+ int where, int size, unsigned int val)
+{
+ void __iomem *addr;
+ struct pci_sys_data *sys = bus->sysdata;
+ struct pci_cfg_windows *cfg = sys->private_data;
+
+ if (cfg->ops->is_valid_cfg_access)
+ if (!cfg->ops->is_valid_cfg_access(bus, devfn))
+ return PCIBIOS_DEVICE_NOT_FOUND;
+
+ addr = cfg->ops->map_bus(bus, devfn, where);
+
+ switch (size) {
+ case 1:
+ writeb(val, addr);
+ break;
+ case 2:
+ writew(val, addr);
+ break;
+ default:
+ writel(val, addr);
+ }
+
+ return PCIBIOS_SUCCESSFUL;
+}
+
+/* Generic PCI CAM/ECAM Configuration Bus Operations */
+
+struct pci_cfg_bus_ops pci_cfg_cam_bus_ops = {
+ .bus_shift = PCI_CFG_CAM_BUS_NUM,
+ .map_bus = pci_cfg_map_bus_cam,
+};
+EXPORT_SYMBOL_GPL(pci_cfg_cam_bus_ops);
+
+struct pci_cfg_bus_ops pci_cfg_ecam_bus_ops = {
+ .bus_shift = PCI_CFG_ECAM_BUS_NUM,
+ .map_bus = pci_cfg_map_bus_ecam,
+};
+EXPORT_SYMBOL_GPL(pci_cfg_ecam_bus_ops);
+
+struct pci_ops pci_cfg_ops = {
+ .read = pci_cfg_read,
+ .write = pci_cfg_write,
+};
+EXPORT_SYMBOL_GPL(pci_cfg_ops);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index aab57b4abe7f..6ebe21ebec1a 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1806,4 +1806,38 @@ static inline struct eeh_dev *pci_dev_to_eeh_dev(struct pci_dev *pdev)
*/
struct pci_dev *pci_find_upstream_pcie_bridge(struct pci_dev *pdev);
+/**
+ * struct pci_cfg_bus_ops - PCI bus configuration operations
+ * @bus_shift: Bus number
+ * @map_bus: Function pointer to get the configuration space address
+ * @is_valid_cfg_access: Function pointer to check for a valid device/function
+ */
+struct pci_cfg_bus_ops {
+ u32 bus_shift;
+ void __iomem *(*map_bus)(struct pci_bus *, unsigned int, int);
+ /*
+ * This function pointer is to check if we are addressing a valid
+ * device's function under a particular bus.
+ */
+ int (*is_valid_cfg_access)(struct pci_bus *, unsigned int);
+};
+
+/**
+ * struct pci_cfg_windows - PCI bus configuration memory windows
+ * @res: Configuration space resource
+ * @bus_range: Bus range
+ * @win: Configuration space memory windows
+ * @ops: PCI bus configuration operations
+ */
+struct pci_cfg_windows {
+ struct resource res;
+ struct resource bus_range;
+ void __iomem **win;
+ struct pci_cfg_bus_ops *ops;
+};
+
+extern struct pci_ops pci_cfg_ops;
+extern struct pci_cfg_bus_ops pci_cfg_ecam_bus_ops;
+extern struct pci_cfg_bus_ops pci_cfg_cam_bus_ops;
+
#endif /* LINUX_PCI_H */
--
1.9.2
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