From b896681f1d5ab491f141f7b2a3c4e672163dc9a5 Mon Sep 17 00:00:00 2001 From: Michael Neuling Date: Wed, 11 Apr 2018 13:37:58 +1000 Subject: [PATCH] powerpc/eeh: Fix enabling bridge MMIO windows On boot we save the configuration space of PCIe bridges. We do this so when we get an EEH event and everything gets reset that we can restore them. Unfortunately we save this state before we've enabled the MMIO space on the bridges. Hence if we have to reset the bridge when we come back MMIO is not enabled and we end up taking an PE freeze when the driver starts accessing again. This patch forces the memory/MMIO and bus mastering on when restoring bridges on EEH. Ideally we'd do this correctly by saving the configuration space writes later, but that will have to come later in a larger EEH rewrite. For now we have this simple fix. The original bug can be triggered on a boston machine by doing: echo 0x8000000000000000 > /sys/kernel/debug/powerpc/PCI0001/err_injct_outbound On boston, this PHB has a PCIe switch on it. Without this patch, you'll see two EEH events, 1 expected and 1 the failure we are fixing here. The second EEH event causes the anything under the PHB to disappear (i.e. the i40e eth). With this patch, only 1 EEH event occurs and devices properly recover. Fixes: e90fcaed4a89 ("powerpc/eeh: Check PCIe link after reset") Cc: stable@vger.kernel.org # v3.11+ Reported-by: Pridhiviraj Paidipeddi Signed-off-by: Michael Neuling Acked-by: Russell Currey Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/eeh_pe.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c index 2d4956e97aa98..ee5a67d57aab8 100644 --- a/arch/powerpc/kernel/eeh_pe.c +++ b/arch/powerpc/kernel/eeh_pe.c @@ -807,7 +807,8 @@ static void eeh_restore_bridge_bars(struct eeh_dev *edev) eeh_ops->write_config(pdn, 15*4, 4, edev->config_space[15]); /* PCI Command: 0x4 */ - eeh_ops->write_config(pdn, PCI_COMMAND, 4, edev->config_space[1]); + eeh_ops->write_config(pdn, PCI_COMMAND, 4, edev->config_space[1] | + PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER); /* Check the PCIe link is ready */ eeh_bridge_check_link(edev); -- 2.39.5