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[1/2] PCI: rcar: Do not abort on too many inbound dma-ranges

Message ID 20190709011559.12379-1-marek.vasut@gmail.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show
Series [1/2] PCI: rcar: Do not abort on too many inbound dma-ranges | expand

Commit Message

Marek Vasut July 9, 2019, 1:15 a.m. UTC 
From: Marek Vasut <marek.vasut+renesas@gmail.com>

In case the "dma-ranges" DT property contains either too many ranges
or the range start address is unaligned in such a way that populating
the range into the controller requires multiple entries, a situation
may occur where all ranges cannot be loaded into the controller.

Currently, the driver refuses to probe in such a situation. Relax this
behavior, load as many ranges as possible and warn if some ranges do
not fit anymore.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-renesas-soc@vger.kernel.org
To: linux-pci@vger.kernel.org
---
 drivers/pci/controller/pcie-rcar.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Geert Uytterhoeven July 9, 2019, 6:58 a.m. UTC | #1 
Hi Marek,

On Tue, Jul 9, 2019 at 3:18 AM <marek.vasut@gmail.com> wrote:
> From: Marek Vasut <marek.vasut+renesas@gmail.com>
>
> In case the "dma-ranges" DT property contains either too many ranges
> or the range start address is unaligned in such a way that populating
> the range into the controller requires multiple entries, a situation
> may occur where all ranges cannot be loaded into the controller.
>
> Currently, the driver refuses to probe in such a situation. Relax this
> behavior, load as many ranges as possible and warn if some ranges do
> not fit anymore.
>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>

Thanks for your patch!

> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -1069,8 +1069,9 @@ static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
>                 idx += 2;
>
>                 if (idx > MAX_NR_INBOUND_MAPS) {
> -                       dev_err(pcie->dev, "Failed to map inbound regions!\n");
> -                       return -EINVAL;
> +                       dev_warn(pcie->dev,
> +                                "Too many inbound regions, not all are mapped.\n");
> +                       break;
>                 }
>         }
>         *index = idx;

The incremented idx is stored here.  Hence for each subsequent call to
rcar_pcie_inbound_ranges() from the loop in rcar_pcie_parse_map_dma_ranges(),
it will write to nonexisting registers.

It seems that can already happen now (but only for the last iteration,
just before it errors out), so probably you want to fix that first, by
moving the check to the start of the loop.

Gr{oetje,eeting}s,

                        Geert
diff mbox series

Patch

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index f6a669a9af41..938adff4148f 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -1069,8 +1069,9 @@  static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
 		idx += 2;
 
 		if (idx > MAX_NR_INBOUND_MAPS) {
-			dev_err(pcie->dev, "Failed to map inbound regions!\n");
-			return -EINVAL;
+			dev_warn(pcie->dev,
+				 "Too many inbound regions, not all are mapped.\n");
+			break;
 		}
 	}
 	*index = idx;