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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-09-19 17:45:07 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-09-20 16:12:54 +1000
commit82ba129baeb1ff72e75d93e70534ba50312153f3 (patch)
treedcd3e60d80f8102c670cb3e6cd3d2e0c7c9deb57 /arch/powerpc/platforms/powernv/pci.c
parentc1a2562ac5edcb3965760f4a37368122d85657af (diff)
downloadvexpress-lsk-82ba129baeb1ff72e75d93e70534ba50312153f3.tar.gz
powerpc/powernv: Handle PCI-X/PCIe reset delay
The firmware doesn't wait after lifting the PCI reset. However it does timestamp it in the device tree. We use that to ensure we wait long enough (3s is our current arbitrary setting) from that timestamp to actually probing the bus. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/platforms/powernv/pci.c')
-rw-r--r--arch/powerpc/platforms/powernv/pci.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c
index 5c175519cf9..85bb66d7f93 100644
--- a/arch/powerpc/platforms/powernv/pci.c
+++ b/arch/powerpc/platforms/powernv/pci.c
@@ -35,6 +35,8 @@
#include "powernv.h"
#include "pci.h"
+/* Delay in usec */
+#define PCI_RESET_DELAY_US 3000000
#define cfg_dbg(fmt...) do { } while(0)
//#define cfg_dbg(fmt...) printk(fmt)
@@ -354,6 +356,35 @@ static void __devinit pnv_pci_dma_dev_setup(struct pci_dev *pdev)
pnv_pci_dma_fallback_setup(hose, pdev);
}
+static int pnv_pci_probe_mode(struct pci_bus *bus)
+{
+ struct pci_controller *hose = pci_bus_to_host(bus);
+ const __be64 *tstamp;
+ u64 now, target;
+
+
+ /* We hijack this as a way to ensure we have waited long
+ * enough since the reset was lifted on the PCI bus
+ */
+ if (bus != hose->bus)
+ return PCI_PROBE_NORMAL;
+ tstamp = of_get_property(hose->dn, "reset-clear-timestamp", NULL);
+ if (!tstamp || !*tstamp)
+ return PCI_PROBE_NORMAL;
+
+ now = mftb() / tb_ticks_per_usec;
+ target = (be64_to_cpup(tstamp) / tb_ticks_per_usec)
+ + PCI_RESET_DELAY_US;
+
+ pr_devel("pci %04d: Reset target: 0x%llx now: 0x%llx\n",
+ hose->global_number, target, now);
+
+ if (now < target)
+ msleep((target - now + 999) / 1000);
+
+ return PCI_PROBE_NORMAL;
+}
+
void __init pnv_pci_init(void)
{
struct device_node *np;
@@ -384,6 +415,7 @@ void __init pnv_pci_init(void)
ppc_md.pci_dma_dev_setup = pnv_pci_dma_dev_setup;
ppc_md.tce_build = pnv_tce_build;
ppc_md.tce_free = pnv_tce_free;
+ ppc_md.pci_probe_mode = pnv_pci_probe_mode;
set_pci_dma_ops(&dma_iommu_ops);
/* Configure MSIs */