Re: [PATCH 1/1] PCI: dwc: Fix BAR0 wrong map to iATU6 after root complex reinit endpoint

Niklas Cassel
2023-12-19T10:07:20Z

On Mon, Dec 18, 2023 at 11:48:43PM -0500, Frank Li wrote:
> 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 s8. Initialize bar_to_atu as -1 to indicate it have
> not allocate atu to the bar.
>
> Reported-by: Niklas Cassel <Niklas.Cassel@wdc.com>
> Close: 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")
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>
> Notes:
> @Niklas:
> I have not test your case. I should be equal to previous's fix in
> mail list.

Hello Frank,

Thank you for sending a proper fix for this!

Personally, I slightly prefer your fix that saves the iatu index + 1, and
keeps 0 to mean unused. That way, you don't need the memset, and you don't
need to change the type to signed, but either way is fine by me, so:

Reviewed-by: Niklas Cassel <niklas.cassel@wdc.com>

>
> drivers/pci/controller/dwc/pcie-designware-ep.c | 11 ++++++++---
> drivers/pci/controller/dwc/pcie-designware.h | 2 +-
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index f6207989fc6ad..0ff5cd64f49b0 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -174,7 +174,7 @@ static int dw_pcie_ep_inbound_atu(struct dw_pcie_ep *ep, u8 func_no, int type,
> u32 free_win;
> struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>
> - if (!ep->bar_to_atu[bar])
> + if (ep->bar_to_atu[bar] < 0)
> free_win = find_first_zero_bit(ep->ib_window_map, pci->num_ib_windows);
> else
> free_win = ep->bar_to_atu[bar];
> @@ -228,14 +228,17 @@ 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];
> + s8 atu_index = ep->bar_to_atu[bar];
> +
> + if (atu_index < 0)
> + return;
>
> __dw_pcie_ep_reset_bar(pci, func_no, bar, epf_bar->flags);
>
> dw_pcie_disable_atu(pci, PCIE_ATU_REGION_DIR_IB, atu_index);
> clear_bit(atu_index, ep->ib_window_map);
> ep->epf_bar[bar] = NULL;
> - ep->bar_to_atu[bar] = 0;
> + ep->bar_to_atu[bar] = -1;
> }
>
> static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
> @@ -767,6 +770,8 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
> return -ENOMEM;
> ep->outbound_addr = addr;
>
> + memset(ep->bar_to_atu, -1, sizeof(ep->bar_to_atu));
> +
> epc = devm_pci_epc_create(dev, &epc_ops);
> if (IS_ERR(epc)) {
> dev_err(dev, "Failed to create epc device\n");
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 55ff76e3d3846..5879907c5cf25 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -362,7 +362,7 @@ struct dw_pcie_ep {
> phys_addr_t phys_base;
> size_t addr_size;
> size_t page_size;
> - u8 bar_to_atu[PCI_STD_NUM_BARS];
> + s8 bar_to_atu[PCI_STD_NUM_BARS];
> phys_addr_t *outbound_addr;
> unsigned long *ib_window_map;
> unsigned long *ob_window_map;
> --
> 2.34.1
>