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SubjectRe: [PATCH V4 15/23] acpi, mcfg: Implement two calls that might be used to inject/remove MCFG region.
On Thu, Feb 04, 2016 at 06:28:53PM +0100, Tomasz Nowicki wrote:
> Lets abstract two calls which allow to inject and remove MCFG regions
> which may come from DSDT table. These calls will be used for x86 and ARM64
> PCI host bridge driver in the later patches.
>
> Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
> Tested-by: Duc Dang <dhdang@apm.com>
> Tested-by: Dongdong Liu <liudongdong3@huawei.com>
> Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
> Tested-by: Graeme Gregory <graeme.gregory@linaro.org>
> Tested-by: Sinan Kaya <okaya@codeaurora.org>
> ---
> drivers/acpi/mcfg.c | 38 ++++++++++++++++++++++++++++++++++++++
> include/linux/pci-acpi.h | 9 +++++++++
> 2 files changed, 47 insertions(+)
>
> diff --git a/drivers/acpi/mcfg.c b/drivers/acpi/mcfg.c
> index 3e1e7be..dca4c4e 100644
> --- a/drivers/acpi/mcfg.c
> +++ b/drivers/acpi/mcfg.c
> @@ -10,6 +10,7 @@
> #include <linux/acpi.h>
> #include <linux/ecam.h>
> #include <linux/pci.h>
> +#include <linux/pci-acpi.h>
>
> #define PREFIX "MCFG: "
>
> @@ -77,6 +78,43 @@ int __init acpi_parse_mcfg(struct acpi_table_header *header)
> return 0;
> }
>
> +int pci_mmcfg_setup_map(struct acpi_pci_root_info *ci)
> +{
> + struct pci_mmcfg_region *cfg;
> + struct acpi_pci_root *root;
> + int seg, start, end, err;
> +
> + root = ci->root;
> + seg = root->segment;
> + start = root->secondary.start;
> + end = root->secondary.end;
> +
> + cfg = pci_mmconfig_lookup(seg, start);
> + if (cfg)
> + return 0;
> +
> + cfg = pci_mmconfig_alloc(seg, start, end, root->mcfg_addr);
> + if (!cfg)
> + return -ENOMEM;
> +
> + err = pci_mmconfig_inject(cfg);
> + return err;

When you integrate Jayachandran's patch this whole function will
become a pci_mmconfig_insert() and that's where hot_added should
be set.

> +}
> +
> +void pci_mmcfg_teardown_map(struct acpi_pci_root_info *ci)
> +{
> + struct acpi_pci_root *root = ci->root;
> + struct pci_mmcfg_region *cfg;
> +
> + cfg = pci_mmconfig_lookup(root->segment, root->secondary.start);
> + if (!cfg)
> + return;
> +
> + if (cfg->hot_added)

Move the hot_added check in pci_mmconfig_delete() (that does the look
up again), we do not want to carry out pci_mmconfig_lookup only to
check that flag here (and we miss rcu locking for the look-up BTW).

Thanks,
Lorenzo

> + pci_mmconfig_delete(root->segment, root->secondary.start,
> + root->secondary.end);
> +}
> +
> int __init __weak acpi_mcfg_check_entry(struct acpi_table_mcfg *mcfg,
> struct acpi_mcfg_allocation *cfg)
> {
> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> index a72e22d..65b91f3 100644
> --- a/include/linux/pci-acpi.h
> +++ b/include/linux/pci-acpi.h
> @@ -80,6 +80,15 @@ extern struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
> void acpi_pci_add_bus(struct pci_bus *bus);
> void acpi_pci_remove_bus(struct pci_bus *bus);
>
> +#ifdef CONFIG_PCI_MMCONFIG
> +int pci_mmcfg_setup_map(struct acpi_pci_root_info *ci);
> +void pci_mmcfg_teardown_map(struct acpi_pci_root_info *ci);
> +#else
> +static inline int pci_mmcfg_setup_map(struct acpi_pci_root_info *ci)
> +{ return 0; }
> +static inline void pci_mmcfg_teardown_map(struct acpi_pci_root_info *ci) { }
> +#endif
> +
> #ifdef CONFIG_ACPI_PCI_SLOT
> void acpi_pci_slot_init(void);
> void acpi_pci_slot_enumerate(struct pci_bus *bus);
> --
> 1.9.1
>

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