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Date: Tue, 20 Oct 2015 08:48:00 -0500
From: Bjorn Helgaas <helgaas@...nel.org>
To: David Daney <ddaney.cavm@...il.com>
Cc: linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
Bjorn Helgaas <bhelgaas@...gle.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
Rafał Miłecki <zajec5@...il.com>,
linux-api@...r.kernel.org,
"Sean O. Stalley" <sean.stalley@...el.com>, yinghai@...nel.org,
rajatxjain@...il.com, gong.chen@...ux.intel.com,
David Daney <david.daney@...ium.com>
Subject: Re: [PATCH v5 2/4] PCI: Add support for Enhanced Allocation devices
On Tue, Oct 06, 2015 at 04:50:36PM -0700, David Daney wrote:
> From: "Sean O. Stalley" <sean.stalley@...el.com>
>
> Add support for devices using Enhanced Allocation entries instead of BARs.
> This patch allows the kernel to parse the EA Extended Capability structure
> in PCI configspace and claim the BAR-equivalent resources.
>
> Signed-off-by: Sean O. Stalley <sean.stalley@...el.com>
> [david.daney@...ium.com: Add more support/checking for Entry Properties,
> allow EA behind bridges, rewrite some error messages.]
> Signed-off-by: David Daney <david.daney@...ium.com>
> ---
> drivers/pci/pci.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> drivers/pci/pci.h | 1 +
> drivers/pci/probe.c | 3 +
> 3 files changed, 186 insertions(+)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 6a9a111..30a90d1 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -2148,6 +2148,188 @@ void pci_pm_init(struct pci_dev *dev)
> }
> }
>
> +static unsigned long pci_ea_set_flags(struct pci_dev *dev, u8 prop)
> +{
> + unsigned long flags = IORESOURCE_PCI_FIXED;
> +
> + switch (prop) {
> + case PCI_EA_P_MEM:
> + case PCI_EA_P_VIRT_MEM:
> + flags |= IORESOURCE_MEM;
> + break;
> + case PCI_EA_P_MEM_PREFETCH:
> + case PCI_EA_P_VIRT_MEM_PREFETCH:
> + flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;
> + break;
> + case PCI_EA_P_IO:
> + flags |= IORESOURCE_IO;
> + break;
> + default:
> + return 0;
> + }
> +
> + return flags;
> +}
> +
> +static struct resource *pci_ea_get_resource(struct pci_dev *dev, u8 bei,
> + u8 prop)
> +{
> + if (bei <= PCI_EA_BEI_BAR5 && prop <= PCI_EA_P_IO)
> + return &dev->resource[bei];
> + else if (bei == PCI_EA_BEI_ROM)
> + return &dev->resource[PCI_ROM_RESOURCE];
> + else
> + return NULL;
> +}
> +
> +/* Read an Enhanced Allocation (EA) entry */
> +static int pci_ea_read(struct pci_dev *dev, int offset)
> +{
> + struct resource *res;
> + int ent_offset = offset;
> + int ent_size;
> + resource_size_t start;
> + resource_size_t end;
> + unsigned long flags;
> + u32 dw0;
> + u32 base;
> + u32 max_offset;
> + u8 prop;
> + bool support_64 = (sizeof(resource_size_t) >= 8);
> +
> + pci_read_config_dword(dev, ent_offset, &dw0);
> + ent_offset += 4;
> +
> + /* Entry size field indicates DWORDs after 1st */
> + ent_size = ((dw0 & PCI_EA_ES) + 1) << 2;
> +
> + if (!(dw0 & PCI_EA_ENABLE)) /* Entry not enabled */
> + goto out;
> +
> + prop = PCI_EA_PP(dw0);
> + /*
> + * If the Property is in the reserved range, try the Secondary
> + * Property instead.
> + */
> + if (prop > PCI_EA_P_BRIDGE_IO && prop < PCI_EA_P_MEM_RESERVED)
> + prop = PCI_EA_SP(dw0);
> + if (prop > PCI_EA_P_BRIDGE_IO)
> + goto out;
> +
> + res = pci_ea_get_resource(dev, PCI_EA_BEI(dw0), prop);
> + if (!res) {
> + dev_err(&dev->dev, "Unsupported EA entry BEI: %u\n",
> + PCI_EA_BEI(dw0));
> + goto out;
> + }
> +
> + flags = pci_ea_set_flags(dev, prop);
> + if (!flags) {
> + dev_err(&dev->dev, "Unsupported EA properties: %u\n", prop);
> + goto out;
> + }
> +
> + /* Read Base */
> + pci_read_config_dword(dev, ent_offset, &base);
> + start = (base & PCI_EA_FIELD_MASK);
> + ent_offset += 4;
> +
> + /* Read MaxOffset */
> + pci_read_config_dword(dev, ent_offset, &max_offset);
> + ent_offset += 4;
> +
> + /* Read Base MSBs (if 64-bit entry) */
> + if (base & PCI_EA_IS_64) {
> + u32 base_upper;
> +
> + pci_read_config_dword(dev, ent_offset, &base_upper);
> + ent_offset += 4;
> +
> + flags |= IORESOURCE_MEM_64;
> +
> + /* entry starts above 32-bit boundary, can't use */
> + if (!support_64 && base_upper)
> + goto out;
> +
> + if (support_64)
> + start |= ((u64)base_upper << 32);
> + }
> +
> + dev_dbg(&dev->dev,
> + "EA (%u,%u) start = %pa\n", PCI_EA_BEI(dw0), prop, &start);
> +
> + end = start + (max_offset | 0x03);
> +
> + /* Read MaxOffset MSBs (if 64-bit entry) */
> + if (max_offset & PCI_EA_IS_64) {
> + u32 max_offset_upper;
> +
> + pci_read_config_dword(dev, ent_offset, &max_offset_upper);
> + ent_offset += 4;
> +
> + flags |= IORESOURCE_MEM_64;
> +
> + /* entry too big, can't use */
> + if (!support_64 && max_offset_upper)
> + goto out;
> +
> + if (support_64)
> + end += ((u64)max_offset_upper << 32);
> + }
> +
> + dev_dbg(&dev->dev,
> + "EA (%u,%u) end = %pa\n", PCI_EA_BEI(dw0), prop, &end);
> +
> + if (end < start) {
> + dev_err(&dev->dev, "EA Entry crosses address boundary\n");
> + goto out;
> + }
> +
> + if (ent_size != ent_offset - offset) {
> + dev_err(&dev->dev,
> + "EA Entry Size (%d) does not match length read (%d)\n",
> + ent_size, ent_offset - offset);
> + goto out;
> + }
> +
> + res->name = pci_name(dev);
> + res->start = start;
> + res->end = end;
> + res->flags = flags;
This is similar to reading a BAR from a normal device; can you print what
we found so it looks similar in dmesg, e.g., similar to what
__pci_read_base() does? Note that "dev_dbg" is not equivalent to
dev_printk(KERN_DEBUG). I want the output in dmesg all the time, without
having to enable something via dyndbg.
> +
> +out:
> + return offset + ent_size;
> +}
> +
> +/* Enhanced Allocation Initalization */
> +void pci_ea_init(struct pci_dev *dev)
> +{
> + int ea;
> + u8 num_ent;
> + int offset;
> + int i;
> +
> + /* find PCI EA capability in list */
> + ea = pci_find_capability(dev, PCI_CAP_ID_EA);
> + if (!ea)
> + return;
> +
> + /* determine the number of entries */
> + pci_bus_read_config_byte(dev->bus, dev->devfn, ea + PCI_EA_NUM_ENT,
> + &num_ent);
> + num_ent &= PCI_EA_NUM_ENT_MASK;
> +
> + offset = ea + PCI_EA_FIRST_ENT;
> +
> + /* Skip DWORD 2 for type 1 functions */
> + if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
> + offset += 4;
> +
> + /* parse each EA entry */
> + for (i = 0; i < num_ent; ++i)
> + offset = pci_ea_read(dev, offset);
> +}
> +
> static void pci_add_saved_cap(struct pci_dev *pci_dev,
> struct pci_cap_saved_state *new_cap)
> {
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 24ba9dc..a160733 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -78,6 +78,7 @@ bool pci_dev_keep_suspended(struct pci_dev *dev);
> void pci_config_pm_runtime_get(struct pci_dev *dev);
> void pci_config_pm_runtime_put(struct pci_dev *dev);
> void pci_pm_init(struct pci_dev *dev);
> +void pci_ea_init(struct pci_dev *dev);
> void pci_allocate_cap_save_buffers(struct pci_dev *dev);
> void pci_free_cap_save_buffers(struct pci_dev *dev);
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 8361d27..4c4af78 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1597,6 +1597,9 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
>
> static void pci_init_capabilities(struct pci_dev *dev)
> {
> + /* Enhanced Allocation */
> + pci_ea_init(dev);
> +
> /* MSI/MSI-X list */
> pci_msi_init_pci_dev(dev);
>
> --
> 1.9.1
>
> --
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