ARM: Introduce pci_common_exit()

In order to support building PCI host drivers as modules, functionality
is required to undo the steps performed by pci_common_init(). The PCI
core provides much of the functionality already, so add a function that
can be called by drivers to wrap the ARM specific bits.
This patch does a number of things to achieve this: it adds a .nr field
to struct pci_sys_data to keep track of the controller number that was
used to initialize it during pci_common_init(). That field is passed to
the new .teardown() callback during cleanup to undo what .setup() did.
Furthermore the list of pci_sys_data structures setup can optionally be
returned via the hw_pci structure's .sys field. If a driver initializes
it, then it is assumed to be an empty list that pci_common_init() will
append to. Otherwise the old behaviour of keeping a local list only is
preserved.
If a driver wants to support unloading, then it needs access to this
list and pass it to pci_common_exit(). This will iterate over the list,
call the new .teardown() callback and remove the root bus associated
with each entry.

vidyas: make similar change for ARM64
based on http://git-master/r/#/c/449135/

Bug 1496843

Change-Id: I1091c287a0e2da82e423abe6870c3a5eb63fa695
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Reviewed-on: http://git-master/r/454900
GVS: Gerrit_Virtual_Submit
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>

diff --git a/arch/arm64/include/asm/mach/pci.h b/arch/arm64/include/asm/mach/pci.h
index 27347e9dc3787f5d65b1fed56b71201055c5c397..2094ede134ce5ac27c4e449570f640b93f109316 100644 (file)
--- a/arch/arm64/include/asm/mach/pci.h
+++ b/arch/arm64/include/asm/mach/pci.h
@@ -25,6 +25,7 @@ struct hw_pci {
        struct pci_ops  *ops;
        int             nr_controllers;
        void            **private_data;
+       struct list_head *sys;
        int             (*setup)(int nr, struct pci_sys_data *);
        struct pci_bus *(*scan)(int nr, struct pci_sys_data *);
        void            (*preinit)(void);
@@ -38,6 +39,7 @@ struct hw_pci {
                                          resource_size_t align);
        void            (*add_bus)(struct pci_bus *bus);
        void            (*remove_bus)(struct pci_bus *bus);
+       void            (*teardown)(int nr, struct pci_sys_data *);
 };
 
 /*
@@ -49,6 +51,7 @@ struct pci_sys_data {
 #endif
        struct list_head node;
        int             busnr;          /* primary bus number                   */
+       int             nr;             /* controller number                    */
        u64             mem_offset;     /* bus->cpu memory mapping offset       */
        unsigned long   io_offset;      /* bus->cpu IO mapping offset           */
        struct pci_bus  *bus;           /* PCI bus                              */
@@ -67,6 +70,7 @@ struct pci_sys_data {
                                          resource_size_t align);
        void            (*add_bus)(struct pci_bus *bus);
        void            (*remove_bus)(struct pci_bus *bus);
+       void            (*teardown)(int nr, struct pci_sys_data *);
        void            *private_data;  /* platform controller private data     */
 };
 
@@ -84,6 +88,8 @@ static inline void pci_common_init(struct hw_pci *hw)
        pci_common_init_dev(NULL, hw);
 }
 
+void pci_common_exit(struct list_head *head);
+
 /*
  * Setup early fixed I/O mapping.
  */

diff --git a/arch/arm64/kernel/bios32.c b/arch/arm64/kernel/bios32.c
index 4c917e0dcb88aa28eaf788f036a47690cfdb164d..0bb0ba2b0c7385116b8178d7f51161b2b0a787ea 100644 (file)
--- a/arch/arm64/kernel/bios32.c
+++ b/arch/arm64/kernel/bios32.c
@@ -482,11 +482,13 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
                sys->domain  = hw->domain;
 #endif
                sys->busnr   = busnr;
+               sys->nr      = nr;
                sys->swizzle = hw->swizzle;
                sys->map_irq = hw->map_irq;
                sys->align_resource = hw->align_resource;
                sys->add_bus = hw->add_bus;
                sys->remove_bus = hw->remove_bus;
+               sys->teardown = hw->teardown;
                INIT_LIST_HEAD(&sys->resources);
 
                if (hw->private_data)
@@ -524,18 +526,24 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
 void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
 {
        struct pci_sys_data *sys;
-       LIST_HEAD(head);
+       struct list_head *head;
+       LIST_HEAD(list);
+
+       if (hw->sys)
+               head = hw->sys;
+       else
+               head = &list;
 
        pci_add_flags(PCI_REASSIGN_ALL_RSRC);
        if (hw->preinit)
                hw->preinit();
-       pcibios_init_hw(parent, hw, &head);
+       pcibios_init_hw(parent, hw, head);
        if (hw->postinit)
                hw->postinit();
 
        pci_fixup_irqs(pcibios_swizzle, pcibios_map_irq);
 
-       list_for_each_entry(sys, &head, node) {
+       list_for_each_entry(sys, head, node) {
                struct pci_bus *bus = sys->bus;
 
                if (!pci_has_flag(PCI_PROBE_ONLY)) {
@@ -561,7 +569,7 @@ void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
                pci_bus_add_devices(bus);
        }
 
-       list_for_each_entry(sys, &head, node) {
+       list_for_each_entry(sys, head, node) {
                struct pci_bus *bus = sys->bus;
 
                /* Configure PCI Express settings */
@@ -574,6 +582,24 @@ void pci_common_init_dev(struct device *parent, struct hw_pci *hw)
        }
 }
 
+void pci_common_exit(struct list_head *head)
+{
+       struct pci_sys_data *sys, *tmp;
+
+       list_for_each_entry_safe(sys, tmp, head, node) {
+               pci_stop_root_bus(sys->bus);
+               pci_remove_root_bus(sys->bus);
+               list_del(&sys->node);
+
+               release_resource(&sys->io_res);
+
+               if (sys->teardown)
+                       sys->teardown(sys->nr, sys);
+
+               kfree(sys);
+       }
+}
+
 #ifndef CONFIG_PCI_HOST_ITE8152
 void pcibios_set_master(struct pci_dev *dev)
 {