[RFC PATCH v2 3/4] PCI: ACPI: Add a generic ACPI based host controller
Jayachandran C
jchandra at broadcom.com
Mon Dec 7 09:20:28 PST 2015
Add a simple ACPI based PCI host controller. This is done by
providing a simple implementation for pci_acpi_scan_root().
The MCFG table is parsed early and saved so that it can be
mapped when ACPI calls pci_acpi_scan_root.
This is enabled only for ARM64 now.
Signed-off-by: Jayachandran C <jchandra at broadcom.com>
---
drivers/pci/host/Kconfig | 7 ++
drivers/pci/host/Makefile | 1 +
drivers/pci/host/pci-host-acpi.c | 209 +++++++++++++++++++++++++++++++++++++++
3 files changed, 217 insertions(+)
create mode 100644 drivers/pci/host/pci-host-acpi.c
diff --git a/drivers/pci/host/Kconfig b/drivers/pci/host/Kconfig
index f131ba9..8321efc 100644
--- a/drivers/pci/host/Kconfig
+++ b/drivers/pci/host/Kconfig
@@ -53,6 +53,13 @@ config PCI_RCAR_GEN2_PCIE
help
Say Y here if you want PCIe controller support on R-Car Gen2 SoCs.
+config PCI_HOST_GENERIC_ACPI
+ bool "Generic ACPI PCI host controller"
+ depends on ARM64 && ACPI
+ help
+ Say Y here if you want to support a simple generic ACPI PCI host
+ controller.
+
config PCI_HOST_GENERIC
bool "Generic PCI host controller"
depends on (ARM || ARM64) && OF
diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
index 9d4d3c6..bc31852 100644
--- a/drivers/pci/host/Makefile
+++ b/drivers/pci/host/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
obj-$(CONFIG_PCI_TEGRA) += pci-tegra.o
obj-$(CONFIG_PCI_RCAR_GEN2) += pci-rcar-gen2.o
obj-$(CONFIG_PCI_RCAR_GEN2_PCIE) += pcie-rcar.o
+obj-$(CONFIG_PCI_HOST_GENERIC_ACPI) += pci-host-acpi.o
obj-$(CONFIG_PCI_HOST_GENERIC) += pci-host-generic.o
obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone-dw.o pci-keystone.o
diff --git a/drivers/pci/host/pci-host-acpi.c b/drivers/pci/host/pci-host-acpi.c
new file mode 100644
index 0000000..38fb589
--- /dev/null
+++ b/drivers/pci/host/pci-host-acpi.c
@@ -0,0 +1,209 @@
+/*
+ * Generic PCI host controller driver for ACPI based systems
+ *
+ * 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 Broadcom Corporation
+ *
+ * Based on drivers/pci/host/pci-host-generic.c
+ * Copyright (C) 2014 ARM Limited
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/acpi.h>
+#include <linux/pci-acpi.h>
+#include <linux/sfi_acpi.h>
+#include <linux/slab.h>
+
+#define PREFIX "pci-host-acpi:"
+#define MCFG_NAMELEN 32
+#define MCFG_SHIFT 20
+
+/* ECFG window for this root bus */
+struct gen_mcfg_window {
+ struct resource res;
+ unsigned int domain_nr;
+ unsigned int bus_start;
+ unsigned int bus_end;
+ char name[MCFG_NAMELEN];
+ void __iomem *win;
+};
+
+/* sysdata pointer is ->root_info */
+struct gen_acpi_pci {
+ struct acpi_pci_root_info root_info;
+ struct gen_mcfg_window cfg;
+};
+
+/* MCFG entries */
+struct mcfg_entry {
+ int segment;
+ int bus_start;
+ int bus_end;
+ u64 addr;
+};
+
+/* Globals */
+static struct mcfg_entries {
+ int size;
+ struct mcfg_entry *entries;
+} mcfg_sav;
+
+/* find mapping of a MCFG area */
+static void __iomem *gen_acpi_map_cfg_bus(struct pci_bus *bus,
+ unsigned int devfn, int where)
+{
+ struct gen_acpi_pci *pci = bus->sysdata;
+ struct gen_mcfg_window *cfg = &pci->cfg;
+
+ if (bus->number < cfg->bus_start || bus->number > cfg->bus_end)
+ return NULL;
+
+ return cfg->win + ((bus->number - cfg->bus_start) << MCFG_SHIFT) +
+ ((devfn << 12) | where);
+}
+
+/* Map the ECFG area for a root bus */
+static int gen_acpi_pci_map_mcfg(struct acpi_pci_root *root,
+ struct gen_acpi_pci *pci)
+{
+ struct gen_mcfg_window *cfg = &pci->cfg;
+ struct acpi_device *device = root->device;
+ void __iomem *vaddr;
+
+ /* if there is info from _CBA, use that, otherwise use MCFG table */
+ if (root->mcfg_addr) {
+ cfg->bus_start = root->secondary.start;
+ cfg->bus_end = root->secondary.end;
+ cfg->res.start = root->mcfg_addr;
+ } else {
+ struct mcfg_entry *e = mcfg_sav.entries;
+ int i, n = mcfg_sav.size;
+
+ for (i = 0; i < n; i++, e++)
+ if (e->segment == root->segment)
+ break;
+ if (i >= n)
+ return -ENODEV;
+ cfg->bus_start = e->bus_start;
+ cfg->bus_end = e->bus_end;
+ cfg->res.start = e->addr;
+ }
+
+ cfg->res.flags = IORESOURCE_MEM;
+ cfg->res.name = cfg->name;
+ cfg->res.end = cfg->res.start +
+ ((cfg->bus_end - cfg->bus_start + 1) << MCFG_SHIFT) - 1;
+ snprintf(cfg->name, MCFG_NAMELEN, "PCI MMCONFIG %04x [bus %02x-%02x]",
+ root->segment, cfg->bus_start, cfg->bus_end);
+
+ /* map ECFG space for the bus range */
+ vaddr = devm_ioremap_resource(&device->dev, &cfg->res);
+ if (IS_ERR(vaddr))
+ return PTR_ERR(vaddr);
+
+ cfg->win = vaddr;
+ return 0;
+}
+
+static struct pci_ops gen_acpi_pci_ops = {
+ .map_bus = gen_acpi_map_cfg_bus,
+ .read = pci_generic_config_read,
+ .write = pci_generic_config_write,
+};
+
+static struct acpi_pci_root_ops pci_acpi_root_ops = {
+ .pci_ops = &gen_acpi_pci_ops,
+};
+
+struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
+{
+ struct acpi_device *device = root->device;
+ struct gen_acpi_pci *pci;
+ struct pci_bus *bus, *child;
+ int err;
+
+ /* allocate acpi_info/sysdata */
+ pci = devm_kzalloc(&device->dev, sizeof(*pci), GFP_KERNEL);
+ if (!pci) {
+ dev_err(&device->dev,
+ "pci_bus %04x:%02x: ignored (out of memory)\n",
+ root->segment, (int)root->secondary.start);
+ return NULL;
+ }
+
+ err = gen_acpi_pci_map_mcfg(root, pci);
+ if (err) {
+ dev_err(&device->dev, "MCFG lookup for domain %d failed",
+ root->segment);
+ return NULL;
+ }
+ bus = acpi_pci_root_create(root, &pci_acpi_root_ops,
+ &pci->root_info, pci);
+ if (!bus) {
+ dev_err(&device->dev, "Scanning rootbus failed");
+ return NULL;
+ }
+
+ list_for_each_entry(child, &bus->children, node)
+ pcie_bus_configure_settings(child);
+
+ return bus;
+}
+
+/* save MCFG entries */
+static __init int handle_mcfg(struct acpi_table_header *header)
+{
+ struct acpi_table_mcfg *mcfg;
+ struct acpi_mcfg_allocation *mptr;
+ struct mcfg_entry *e;
+ int i, n;
+
+ if (!header)
+ return -EINVAL;
+
+ mcfg = (struct acpi_table_mcfg *)header;
+ mptr = (struct acpi_mcfg_allocation *) &mcfg[1];
+ n = (header->length - sizeof(*mcfg)) / sizeof(*mptr);
+ if (n <= 0 || n > 255) {
+ pr_err(PREFIX " MCFG has incorrect entries (%d).\n", n);
+ return -EINVAL;
+ }
+ mcfg_sav.entries = e = kcalloc(n, sizeof(*e), GFP_KERNEL);
+ if (e == NULL)
+ return -ENOMEM;
+ mcfg_sav.size = n;
+ for (i = 0; i < n; i++, e++, mptr++) {
+ e->segment = mptr->pci_segment;
+ e->bus_start = mptr->start_bus_number;
+ e->bus_end = mptr->end_bus_number;
+ e->addr = mptr->address;
+ }
+ return 0;
+}
+
+void __init pci_mmcfg_late_init(void)
+{
+ int err;
+
+ err = acpi_sfi_table_parse(ACPI_SIG_MCFG, handle_mcfg);
+ if (err) {
+ pr_err(PREFIX " Failed to parse MCFG (%d)\n", err);
+ mcfg_sav.size = -1;
+ } else {
+ pr_info(PREFIX " MCFG table at %p, %d entries.\n",
+ mcfg_sav.entries, mcfg_sav.size);
+ }
+}
--
1.9.1
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