[PATCH v4 7/9] x86, pci, ecam: mmconfig_64.c becomes default implementation for ECAM driver.
From: Rob Herring <hidden>
Date: 2015-03-11 15:37:54
Also in:
linux-acpi, linux-pci, lkml
On Wed, Mar 11, 2015 at 9:12 AM, Tomasz Nowicki [off-list ref] wrote:
Architectures which want to take advantage of ECAM generic goodness
This is not necessarily an architecture decision. It is likely per host.
should select CONFIG_PCI_ECAM_GENERIC. Otherwise, like x86 32bits machines, are obligated to provide own low-level ECAM calls. Signed-off-by: Tomasz Nowicki <redacted> ---
[...]
quoted hunk ↗ jump to hunk
diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c index c588234..796b6e7 100644 --- a/drivers/pci/ecam.c +++ b/drivers/pci/ecam.c@@ -23,6 +23,119 @@ static DEFINE_MUTEX(pci_mmcfg_lock); LIST_HEAD(pci_mmcfg_list); +#ifdef CONFIG_GENERIC_PCI_ECAM +static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, + unsigned int devfn) +{ + struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus); + + if (cfg && cfg->virt) + return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12)); + return NULL; +} + +int pci_mmcfg_read(unsigned int seg, unsigned int bus, + unsigned int devfn, int reg, int len, u32 *value) +{ + char __iomem *addr; + + /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ + if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) { +err: *value = -1; + return -EINVAL; + } + + rcu_read_lock();
What is the purpose of the rcu lock other than the old implementation had it?
+ addr = pci_dev_base(seg, bus, devfn);
The .map_bus op provides the same function if you restructure to use the generic accessors.
+ if (!addr) {
+ rcu_read_unlock();
+ goto err;
+ }
+
+ *value = pci_mmio_read(len, addr + reg);
+ rcu_read_unlock();
+
+ return 0;
+}
+
+int pci_mmcfg_write(unsigned int seg, unsigned int bus,
+ unsigned int devfn, int reg, int len, u32 value)
+{
+ char __iomem *addr;
+
+ /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
+ if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
+ return -EINVAL;
+
+ rcu_read_lock();
+ addr = pci_dev_base(seg, bus, devfn);
+ if (!addr) {
+ rcu_read_unlock();
+ return -EINVAL;
+ }
+
+ pci_mmio_write(len, addr + reg, value);
+ rcu_read_unlock();
+
+ return 0;
+}
+
+static void __iomem *mcfg_ioremap(struct pci_mmcfg_region *cfg)
+{
+ void __iomem *addr;
+ u64 start, size;
+ int num_buses;
+
+ start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
+ num_buses = cfg->end_bus - cfg->start_bus + 1;
+ size = PCI_MMCFG_BUS_OFFSET(num_buses);
+ addr = ioremap_nocache(start, size);
+ if (addr)
+ addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
+ return addr;
+}
+
+int __init pci_mmcfg_arch_init(void)Where would this be called for the case of the generic host and using DT? Rob