On Wed, Mar 13, 2013 at 5:27 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> From: Ram Pai <linuxram@xxxxxxxxxx>
>
> Currently pci_dev structure holds an array of 17 PCI resources; six base
> BARs, one ROM BAR, four BRIDGE BARs, six sriov BARs. This is wasteful.
> A bridge device just needs the 4 bridge resources. A non-bridge device
> just needs the six base resources and one ROM resource. The sriov
> resources are needed only if the device has SRIOV capability.
>
> The pci_dev structure needs to be re-organized to avoid unnecessary
> bloating. However too much code outside the pci-bus driver, assumes the
> internal details of the pci_dev structure, thus making it hard to
> re-organize the datastructure.
>
> As a first step this patch provides generic methods to access the
> resource structure of the pci_dev.
>
> Finally we can re-organize the resource structure in the pci_dev
> structure and correspondingly update the methods.
>
> -v2: Consolidated iterator interface as per Bjorn's suggestion.
> -v3: Add the idx back - Yinghai Lu
> -v7: Change to use bitmap for searching - Yinghai Lu
> -v8: Fix acpiphp module compiling error that is found by
> Steven Newbury <steve@xxxxxxxxxxxxxxx> - Yinghai Lu
>
> Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> ---
> drivers/pci/probe.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/pci.h | 24 ++++++++++++++++++++++++
> 2 files changed, 72 insertions(+)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 1df75f7..ac751a6 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -123,6 +123,54 @@ int pci_dev_resource_idx(struct pci_dev *dev, struct resource *res)
> return -1;
> }
>
> +static void __init_res_idx_mask(unsigned long *mask, int flag)
> +{
> + bitmap_zero(mask, PCI_NUM_RESOURCES);
> + if (flag & PCI_STD_RES)
> + bitmap_set(mask, PCI_STD_RESOURCES,
> + PCI_STD_RESOURCE_END - PCI_STD_RESOURCES + 1);
> + if (flag & PCI_ROM_RES)
> + bitmap_set(mask, PCI_ROM_RESOURCE, 1);
> +#ifdef CONFIG_PCI_IOV
> + if (flag & PCI_IOV_RES)
> + bitmap_set(mask, PCI_IOV_RESOURCES,
> + PCI_IOV_RESOURCE_END - PCI_IOV_RESOURCES + 1);
> +#endif
> + if (flag & PCI_BRIDGE_RES)
> + bitmap_set(mask, PCI_BRIDGE_RESOURCES,
> + PCI_BRIDGE_RESOURCE_END - PCI_BRIDGE_RESOURCES + 1);
> +}
> +
> +static DECLARE_BITMAP(res_idx_mask[1 << PCI_RES_BLOCK_NUM], PCI_NUM_RESOURCES);
> +static int __init pci_res_idx_mask_init(void)
> +{
> + int i;
> +
> + for (i = 0; i < (1 << PCI_RES_BLOCK_NUM); i++)
> + __init_res_idx_mask(res_idx_mask[i], i);
> +
> + return 0;
> +}
> +postcore_initcall(pci_res_idx_mask_init);
> +
> +static inline unsigned long *get_res_idx_mask(int flag)
> +{
> + return res_idx_mask[flag & ((1 << PCI_RES_BLOCK_NUM) - 1)];
> +}
> +
> +int pci_next_resource_idx(int i, int flag)
> +{
> + i++;
> + if (i < PCI_NUM_RESOURCES)
> + i = find_next_bit(get_res_idx_mask(flag), PCI_NUM_RESOURCES, i);
> +
> + if (i < PCI_NUM_RESOURCES)
> + return i;
> +
> + return -1;
> +}
> +EXPORT_SYMBOL(pci_next_resource_idx);
> +
> static u64 pci_size(u64 base, u64 maxbase, u64 mask)
> {
> u64 size = mask & maxbase; /* Find the significant bits */
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index aefff8b..127a856 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -341,6 +341,30 @@ struct pci_dev {
> struct resource *pci_dev_resource_n(struct pci_dev *dev, int n);
> int pci_dev_resource_idx(struct pci_dev *dev, struct resource *res);
>
> +#define PCI_STD_RES (1<<0)
> +#define PCI_ROM_RES (1<<1)
> +#define PCI_IOV_RES (1<<2)
> +#define PCI_BRIDGE_RES (1<<3)
> +#define PCI_RES_BLOCK_NUM 4
> +
> +#define PCI_ALL_RES (PCI_STD_RES | PCI_ROM_RES | PCI_BRIDGE_RES | PCI_IOV_RES)
> +#define PCI_NOSTD_RES (PCI_ALL_RES & ~PCI_STD_RES)
> +#define PCI_NOIOV_RES (PCI_ALL_RES & ~PCI_IOV_RES)
> +#define PCI_NOROM_RES (PCI_ALL_RES & ~PCI_ROM_RES)
> +#define PCI_NOBRIDGE_RES (PCI_ALL_RES & ~PCI_BRIDGE_RES)
> +#define PCI_STD_ROM_RES (PCI_STD_RES | PCI_ROM_RES)
> +#define PCI_STD_IOV_RES (PCI_STD_RES | PCI_IOV_RES)
> +#define PCI_STD_ROM_IOV_RES (PCI_STD_RES | PCI_ROM_RES | PCI_IOV_RES)
> +
> +int pci_next_resource_idx(int i, int flag);
> +
> +#define for_each_pci_resource(dev, res, i, flag) \
> + for (i = pci_next_resource_idx(-1, flag), \
> + res = pci_dev_resource_n(dev, i); \
> + res; \
> + i = pci_next_resource_idx(i, flag), \
> + res = pci_dev_resource_n(dev, i))
> +
> static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
> {
> #ifdef CONFIG_PCI_IOV
I think this turned out to be a disaster, with all the bitmaps and
helper functions. Filtering in the bodies of the
for_each_pci_resource() users has *got* to be better. That probably
requires a wrapper struct around the struct resource. Or possibly
having a wrapper struct with a "type" or "flags" field would make
filtering in for_each_pci_resources() itself cleaner to implement.
I think it would also help if we got rid of all the "PCI_NO*_RES"
definitions and just had the users explicitly specify what they *do*
want.
Bjorn
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