linux/drivers/pci/host/pcie-iproc-platform.c
Ray Jui 3bc2b23488 PCI: iproc: Add iProc PCIe MSI support
Add PCIe MSI support for both PAXB and PAXC interfaces on all iProc-based
platforms.

The iProc PCIe MSI support deploys an event queue-based implementation.
Each event queue is serviced by a GIC interrupt and can support up to 64
MSI vectors.  Host memory is allocated for the event queues, and each event
queue consists of 64 word-sized entries.  MSI data is written to the lower
16-bit of each entry, whereas the upper 16-bit of the entry is reserved for
the controller for internal processing.

Each event queue is tracked by a head pointer and tail pointer.  Head
pointer indicates the next entry in the event queue to be processed by
the driver and is updated by the driver after processing is done.
The controller uses the tail pointer as the next MSI data insertion
point.  The controller ensures MSI data is flushed to host memory before
updating the tail pointer and then triggering the interrupt.

MSI IRQ affinity is supported by evenly distributing the interrupts to each
CPU core.  MSI vector is moved from one GIC interrupt to another in order
to steer to the target CPU.

Therefore, the actual number of supported MSI vectors is:

  M * 64 / N

where M denotes the number of GIC interrupts (event queues), and N denotes
the number of CPU cores.

This iProc event queue-based MSI support should not be used with newer
platforms with integrated MSI support in the GIC (e.g., giv2m or
gicv3-its).

[bhelgaas: fold in Kconfig fixes from Arnd Bergmann <arnd@arndb.de>]
Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Anup Patel <anup.patel@broadcom.com>
Reviewed-by: Vikram Prakash <vikramp@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
2016-01-06 18:04:35 -06:00

149 lines
3.7 KiB
C

/*
* Copyright (C) 2015 Broadcom Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/phy/phy.h>
#include "pcie-iproc.h"
static const struct of_device_id iproc_pcie_of_match_table[] = {
{
.compatible = "brcm,iproc-pcie",
.data = (int *)IPROC_PCIE_PAXB,
}, {
.compatible = "brcm,iproc-pcie-paxc",
.data = (int *)IPROC_PCIE_PAXC,
},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, iproc_pcie_of_match_table);
static int iproc_pcie_pltfm_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id;
struct iproc_pcie *pcie;
struct device_node *np = pdev->dev.of_node;
struct resource reg;
resource_size_t iobase = 0;
LIST_HEAD(res);
int ret;
of_id = of_match_device(iproc_pcie_of_match_table, &pdev->dev);
if (!of_id)
return -EINVAL;
pcie = devm_kzalloc(&pdev->dev, sizeof(struct iproc_pcie), GFP_KERNEL);
if (!pcie)
return -ENOMEM;
pcie->dev = &pdev->dev;
pcie->type = (enum iproc_pcie_type)of_id->data;
platform_set_drvdata(pdev, pcie);
ret = of_address_to_resource(np, 0, &reg);
if (ret < 0) {
dev_err(pcie->dev, "unable to obtain controller resources\n");
return ret;
}
pcie->base = devm_ioremap(pcie->dev, reg.start, resource_size(&reg));
if (!pcie->base) {
dev_err(pcie->dev, "unable to map controller registers\n");
return -ENOMEM;
}
pcie->base_addr = reg.start;
if (of_property_read_bool(np, "brcm,pcie-ob")) {
u32 val;
ret = of_property_read_u32(np, "brcm,pcie-ob-axi-offset",
&val);
if (ret) {
dev_err(pcie->dev,
"missing brcm,pcie-ob-axi-offset property\n");
return ret;
}
pcie->ob.axi_offset = val;
ret = of_property_read_u32(np, "brcm,pcie-ob-window-size",
&val);
if (ret) {
dev_err(pcie->dev,
"missing brcm,pcie-ob-window-size property\n");
return ret;
}
pcie->ob.window_size = (resource_size_t)val * SZ_1M;
if (of_property_read_bool(np, "brcm,pcie-ob-oarr-size"))
pcie->ob.set_oarr_size = true;
pcie->need_ob_cfg = true;
}
/* PHY use is optional */
pcie->phy = devm_phy_get(&pdev->dev, "pcie-phy");
if (IS_ERR(pcie->phy)) {
if (PTR_ERR(pcie->phy) == -EPROBE_DEFER)
return -EPROBE_DEFER;
pcie->phy = NULL;
}
ret = of_pci_get_host_bridge_resources(np, 0, 0xff, &res, &iobase);
if (ret) {
dev_err(pcie->dev,
"unable to get PCI host bridge resources\n");
return ret;
}
pcie->map_irq = of_irq_parse_and_map_pci;
ret = iproc_pcie_setup(pcie, &res);
if (ret)
dev_err(pcie->dev, "PCIe controller setup failed\n");
pci_free_resource_list(&res);
return ret;
}
static int iproc_pcie_pltfm_remove(struct platform_device *pdev)
{
struct iproc_pcie *pcie = platform_get_drvdata(pdev);
return iproc_pcie_remove(pcie);
}
static struct platform_driver iproc_pcie_pltfm_driver = {
.driver = {
.name = "iproc-pcie",
.of_match_table = of_match_ptr(iproc_pcie_of_match_table),
},
.probe = iproc_pcie_pltfm_probe,
.remove = iproc_pcie_pltfm_remove,
};
module_platform_driver(iproc_pcie_pltfm_driver);
MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
MODULE_DESCRIPTION("Broadcom iPROC PCIe platform driver");
MODULE_LICENSE("GPL v2");