Messages in this thread Patch in this message | | | From | Frank Li <> | Subject | [PATCH v2 1/1] PCI: dwc: Fix index 0 incorrectly being interpreted as a free ATU slot | Date | Mon, 4 Mar 2024 17:46:16 -0500 |
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dw_pcie_ep_inbound_atu() { ... if (!ep->bar_to_atu[bar]) free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows); else free_win = ep->bar_to_atu[bar]; ... }
The atu index 0 is valid case for atu number. The find_first_zero_bit() will return 6 when second time call into this function if atu is 0. Suppose it should use branch 'free_win = ep->bar_to_atu[bar]'.
Change 'bar_to_atu' to free_win + 1. Initialize bar_to_atu as 0 to indicate it have not allocate atu to the bar.
Reported-by: Niklas Cassel <Niklas.Cassel@wdc.com> Closes: https://lore.kernel.org/linux-pci/ZXt2A+Fusfz3luQV@x1-carbon/T/#u Fixes: 4284c88fff0e ("PCI: designware-ep: Allow pci_epc_set_bar() update inbound map address") Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com> Signed-off-by: Frank Li <Frank.Li@nxp.com> ---
Notes: Change from v1 to v2 - update subject - use free_win + 1 solution - still leave MAX_IATU_IN as 256. I am not sure if there are platfrom have 256 ATU. Suppose it only use max 6 in current EP framework. - @Niklas, can you help test it. My platform become unstable today.
drivers/pci/controller/dwc/pcie-designware-ep.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c index 5befed2dc02b7..ba932bafdb230 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -139,7 +139,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type, if (!ep->bar_to_atu[bar]) free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows); else - free_win = ep->bar_to_atu[bar]; + free_win = ep->bar_to_atu[bar] - 1; if (free_win >= pci->num_ib_windows) { dev_err(pci->dev, "No free inbound window\n"); @@ -153,7 +153,11 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type, return ret; } - ep->bar_to_atu[bar] = free_win; + /* + * Always increment free_win before assignment, since value 0 is used to identify + * unallocated mapping. + */ + ep->bar_to_atu[bar] = free_win + 1; set_bit(free_win, ep->ib_window_map); return 0; @@ -190,7 +194,10 @@ static void dw_pcie_ep_clear_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, struct dw_pcie_ep *ep = epc_get_drvdata(epc); struct dw_pcie *pci = to_dw_pcie_from_ep(ep); enum pci_barno bar = epf_bar->barno; - u32 atu_index = ep->bar_to_atu[bar]; + u32 atu_index = ep->bar_to_atu[bar] - 1; + + if (!ep->bar_to_atu[bar]) + return; __dw_pcie_ep_reset_bar(pci, func_no, bar, epf_bar->flags); -- 2.34.1
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