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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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2dd9c11b9d
This patch leverages 'struct pci_host_bridge' from the PCI subsystem in order to free the pci_controller only after the last reference to its devices is dropped (avoiding an oops in pcibios_release_device() if the last reference is dropped after pcibios_free_controller()). The patch relies on pci_host_bridge.release_fn() (and .release_data), which is called automatically by the PCI subsystem when the root bus is released (i.e., the last reference is dropped). Those fields are set via pci_set_host_bridge_release() (e.g. in the platform-specific implementation of pcibios_root_bridge_prepare()). It introduces the 'pcibios_free_controller_deferred()' .release_fn() and it expects .release_data to hold a pointer to the pci_controller. The function implictly calls 'pcibios_free_controller()', so an user must *NOT* explicitly call it if using the new _deferred() callback. The functionality is enabled for pseries (although it isn't platform specific, and may be used by cxl). Details on not-so-elegant design choices: - Use 'pci_host_bridge.release_data' field as pointer to associated 'struct pci_controller' so *not* to 'pci_bus_to_host(bridge->bus)' in pcibios_free_controller_deferred(). That's because pci_remove_root_bus() sets 'host_bridge->bus = NULL' (so, if the last reference is released after pci_remove_root_bus() runs, which eventually reaches pcibios_free_controller_deferred(), that would hit a null pointer dereference). The cxl/vphb.c code calls pci_remove_root_bus(), and the cxl folks are interested in this fix. Test-case #1 (hold references) # ls -ld /sys/block/sd* | grep -m1 0021:01:00.0 <...> /sys/block/sdaa -> ../devices/pci0021:01/0021:01:00.0/<...> # ls -ld /sys/block/sd* | grep -m1 0021:01:00.1 <...> /sys/block/sdab -> ../devices/pci0021:01/0021:01:00.1/<...> # cat >/dev/sdaa & pid1=$! # cat >/dev/sdab & pid2=$! # drmgr -w 5 -d 1 -c phb -s 'PHB 33' -r Validating PHB DLPAR capability...yes. [ 594.306719] pci_hp_remove_devices: PCI: Removing devices on bus 0021:01 [ 594.306738] pci_hp_remove_devices: Removing 0021:01:00.0... ... [ 598.236381] pci_hp_remove_devices: Removing 0021:01:00.1... ... [ 611.972077] pci_bus 0021:01: busn_res: [bus 01-ff] is released [ 611.972140] rpadlpar_io: slot PHB 33 removed # kill -9 $pid1 # kill -9 $pid2 [ 632.918088] pcibios_free_controller_deferred: domain 33, dynamic 1 Test-case #2 (don't hold references) # drmgr -w 5 -d 1 -c phb -s 'PHB 33' -r Validating PHB DLPAR capability...yes. [ 916.357363] pci_hp_remove_devices: PCI: Removing devices on bus 0021:01 [ 916.357386] pci_hp_remove_devices: Removing 0021:01:00.0... ... [ 920.566527] pci_hp_remove_devices: Removing 0021:01:00.1... ... [ 933.955873] pci_bus 0021:01: busn_res: [bus 01-ff] is released [ 933.955977] pcibios_free_controller_deferred: domain 33, dynamic 1 [ 933.955999] rpadlpar_io: slot PHB 33 removed Suggested-By: Gavin Shan <gwshan@linux.vnet.ibm.com> Signed-off-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com> Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> Tested-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com> # cxl Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
177 lines
4.4 KiB
C
177 lines
4.4 KiB
C
/*
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* Copyright (C) 2001 Dave Engebretsen, IBM Corporation
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* Copyright (C) 2003 Anton Blanchard <anton@au.ibm.com>, IBM
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*
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* pSeries specific routines for PCI.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/init.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <linux/string.h>
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#include <asm/eeh.h>
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#include <asm/pci-bridge.h>
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#include <asm/prom.h>
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#include <asm/ppc-pci.h>
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#include "pseries.h"
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#if 0
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void pcibios_name_device(struct pci_dev *dev)
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{
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struct device_node *dn;
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/*
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* Add IBM loc code (slot) as a prefix to the device names for service
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*/
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dn = pci_device_to_OF_node(dev);
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if (dn) {
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const char *loc_code = of_get_property(dn, "ibm,loc-code",
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NULL);
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if (loc_code) {
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int loc_len = strlen(loc_code);
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if (loc_len < sizeof(dev->dev.name)) {
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memmove(dev->dev.name+loc_len+1, dev->dev.name,
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sizeof(dev->dev.name)-loc_len-1);
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memcpy(dev->dev.name, loc_code, loc_len);
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dev->dev.name[loc_len] = ' ';
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dev->dev.name[sizeof(dev->dev.name)-1] = '\0';
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}
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}
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}
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}
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DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, pcibios_name_device);
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#endif
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static void __init pSeries_request_regions(void)
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{
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if (!isa_io_base)
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return;
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request_region(0x20,0x20,"pic1");
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request_region(0xa0,0x20,"pic2");
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request_region(0x00,0x20,"dma1");
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request_region(0x40,0x20,"timer");
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request_region(0x80,0x10,"dma page reg");
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request_region(0xc0,0x20,"dma2");
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}
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void __init pSeries_final_fixup(void)
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{
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pSeries_request_regions();
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eeh_addr_cache_build();
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}
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/*
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* Assume the winbond 82c105 is the IDE controller on a
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* p610/p615/p630. We should probably be more careful in case
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* someone tries to plug in a similar adapter.
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*/
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static void fixup_winbond_82c105(struct pci_dev* dev)
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{
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int i;
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unsigned int reg;
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if (!machine_is(pseries))
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return;
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printk("Using INTC for W82c105 IDE controller.\n");
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pci_read_config_dword(dev, 0x40, ®);
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/* Enable LEGIRQ to use INTC instead of ISA interrupts */
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pci_write_config_dword(dev, 0x40, reg | (1<<11));
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for (i = 0; i < DEVICE_COUNT_RESOURCE; ++i) {
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/* zap the 2nd function of the winbond chip */
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if (dev->resource[i].flags & IORESOURCE_IO
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&& dev->bus->number == 0 && dev->devfn == 0x81)
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dev->resource[i].flags &= ~IORESOURCE_IO;
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if (dev->resource[i].start == 0 && dev->resource[i].end) {
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dev->resource[i].flags = 0;
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dev->resource[i].end = 0;
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}
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}
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}
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DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_WINBOND, PCI_DEVICE_ID_WINBOND_82C105,
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fixup_winbond_82c105);
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int pseries_root_bridge_prepare(struct pci_host_bridge *bridge)
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{
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struct device_node *dn, *pdn;
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struct pci_bus *bus;
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u32 pcie_link_speed_stats[2];
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int rc;
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bus = bridge->bus;
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/* Rely on the pcibios_free_controller_deferred() callback. */
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pci_set_host_bridge_release(bridge, pcibios_free_controller_deferred,
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(void *) pci_bus_to_host(bus));
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dn = pcibios_get_phb_of_node(bus);
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if (!dn)
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return 0;
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for (pdn = dn; pdn != NULL; pdn = of_get_next_parent(pdn)) {
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rc = of_property_read_u32_array(pdn,
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"ibm,pcie-link-speed-stats",
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&pcie_link_speed_stats[0], 2);
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if (!rc)
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break;
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}
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of_node_put(pdn);
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if (rc) {
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pr_debug("no ibm,pcie-link-speed-stats property\n");
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return 0;
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}
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switch (pcie_link_speed_stats[0]) {
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case 0x01:
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bus->max_bus_speed = PCIE_SPEED_2_5GT;
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break;
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case 0x02:
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bus->max_bus_speed = PCIE_SPEED_5_0GT;
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break;
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case 0x04:
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bus->max_bus_speed = PCIE_SPEED_8_0GT;
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break;
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default:
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bus->max_bus_speed = PCI_SPEED_UNKNOWN;
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break;
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}
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switch (pcie_link_speed_stats[1]) {
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case 0x01:
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bus->cur_bus_speed = PCIE_SPEED_2_5GT;
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break;
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case 0x02:
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bus->cur_bus_speed = PCIE_SPEED_5_0GT;
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break;
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case 0x04:
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bus->cur_bus_speed = PCIE_SPEED_8_0GT;
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break;
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default:
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bus->cur_bus_speed = PCI_SPEED_UNKNOWN;
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break;
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}
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return 0;
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}
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