diff mbox series

pci: loongson: Workaround MIPS firmware MRRS settings

Message ID 20230718133259.2867432-1-jiaxun.yang@flygoat.com (mailing list archive)
State Superseded
Delegated to: Krzysztof Wilczyński
Headers show
Series pci: loongson: Workaround MIPS firmware MRRS settings | expand

Commit Message

Jiaxun Yang July 18, 2023, 1:32 p.m. UTC 
This is a partial revert of commit 8b3517f88ff2 ("PCI:
loongson: Prevent LS7A MRRS increases") for MIPS based Loongson.

There are many MIPS based Loongson systems in wild that
shipped with firmware which does not set maximum MRRS properly.

Limiting MRRS to 256 for all as MIPS Loongson comes with higher
MRRS support is considered rare.

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217680
Fixes: 8b3517f88ff2 ("PCI: loongson: Prevent LS7A MRRS increases")
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
 drivers/pci/controller/pci-loongson.c | 38 +++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

Comments

Huacai Chen July 18, 2023, 2:46 p.m. UTC | #1 
Hi, Jiaxun,

On Tue, Jul 18, 2023 at 9:33 PM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>
> This is a partial revert of commit 8b3517f88ff2 ("PCI:
> loongson: Prevent LS7A MRRS increases") for MIPS based Loongson.
>
> There are many MIPS based Loongson systems in wild that
> shipped with firmware which does not set maximum MRRS properly.
>
> Limiting MRRS to 256 for all as MIPS Loongson comes with higher
> MRRS support is considered rare.
>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217680
> Fixes: 8b3517f88ff2 ("PCI: loongson: Prevent LS7A MRRS increases")
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> ---
>  drivers/pci/controller/pci-loongson.c | 38 +++++++++++++++++++++++++++
>  1 file changed, 38 insertions(+)
>
> diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
> index fe0f732f6e43..1cc3a5535dac 100644
> --- a/drivers/pci/controller/pci-loongson.c
> +++ b/drivers/pci/controller/pci-loongson.c
> @@ -108,6 +108,44 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
>  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
>                         DEV_LS7A_PCIE_PORT6, loongson_mrrs_quirk);
>
> +#ifdef CONFIG_MIPS
> +static void loongson_firmware_mrrs_quirk(struct pci_dev *pdev)
From my point of view, loongson_old_mrrs_quirk() may be better.

Huacai

> +{
> +       struct pci_bus *bus = pdev->bus;
> +       struct pci_dev *bridge;
> +       static const struct pci_device_id bridge_devids[] = {
> +               { PCI_VDEVICE(LOONGSON, DEV_LS2K_PCIE_PORT0) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT0) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT1) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT2) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT3) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT4) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT5) },
> +               { PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT6) },
> +               { 0, },
> +       };
> +
> +       /* look for the matching bridge */
> +       while (!pci_is_root_bus(bus)) {
> +               bridge = bus->self;
> +               bus = bus->parent;
> +               /*
> +                * There are still some wild MIPS Loongson firmware won't
> +                * set MRRS properly. Limiting MRRS to 256 as MIPS Loongson
> +                * comes with higher MRRS support is considered rare.
> +                */
> +               if (pci_match_id(bridge_devids, bridge)) {
> +                       if (pcie_get_readrq(pdev) > 256) {
> +                               pci_info(pdev, "limiting MRRS to 256\n");
> +                               pcie_set_readrq(pdev, 256);
> +                       }
> +                       break;
> +               }
> +       }
> +}
> +DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_firmware_mrrs_quirk);
> +#endif
> +
>  static void loongson_pci_pin_quirk(struct pci_dev *pdev)
>  {
>         pdev->pin = 1 + (PCI_FUNC(pdev->devfn) & 3);
> --
> 2.39.2
>
Jiaxun Yang July 19, 2023, 8:24 a.m. UTC | #2 
在 2023/7/18 22:46, Huacai Chen 写道:
> Hi, Jiaxun,
>
> On Tue, Jul 18, 2023 at 9:33 PM Jiaxun Yang <jiaxun.yang@flygoat.com> wrote:
>> This is a partial revert of commit 8b3517f88ff2 ("PCI:
>> loongson: Prevent LS7A MRRS increases") for MIPS based Loongson.
>>
>> There are many MIPS based Loongson systems in wild that
>> shipped with firmware which does not set maximum MRRS properly.
>>
>> Limiting MRRS to 256 for all as MIPS Loongson comes with higher
>> MRRS support is considered rare.
>>
>> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217680
>> Fixes: 8b3517f88ff2 ("PCI: loongson: Prevent LS7A MRRS increases")
>> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
>> ---
>>   drivers/pci/controller/pci-loongson.c | 38 +++++++++++++++++++++++++++
>>   1 file changed, 38 insertions(+)
>>
>> diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
>> index fe0f732f6e43..1cc3a5535dac 100644
>> --- a/drivers/pci/controller/pci-loongson.c
>> +++ b/drivers/pci/controller/pci-loongson.c
>> @@ -108,6 +108,44 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
>>   DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
>>                          DEV_LS7A_PCIE_PORT6, loongson_mrrs_quirk);
>>
>> +#ifdef CONFIG_MIPS
>> +static void loongson_firmware_mrrs_quirk(struct pci_dev *pdev)
>  From my point of view, loongson_old_mrrs_quirk() may be better.

Make sense to me, will rename in v2.

Thanks
- Jiaxun
diff mbox series

Patch

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index fe0f732f6e43..1cc3a5535dac 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -108,6 +108,44 @@  DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
 			DEV_LS7A_PCIE_PORT6, loongson_mrrs_quirk);
 
+#ifdef CONFIG_MIPS
+static void loongson_firmware_mrrs_quirk(struct pci_dev *pdev)
+{
+	struct pci_bus *bus = pdev->bus;
+	struct pci_dev *bridge;
+	static const struct pci_device_id bridge_devids[] = {
+		{ PCI_VDEVICE(LOONGSON, DEV_LS2K_PCIE_PORT0) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT0) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT1) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT2) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT3) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT4) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT5) },
+		{ PCI_VDEVICE(LOONGSON, DEV_LS7A_PCIE_PORT6) },
+		{ 0, },
+	};
+
+	/* look for the matching bridge */
+	while (!pci_is_root_bus(bus)) {
+		bridge = bus->self;
+		bus = bus->parent;
+		/*
+		 * There are still some wild MIPS Loongson firmware won't
+		 * set MRRS properly. Limiting MRRS to 256 as MIPS Loongson
+		 * comes with higher MRRS support is considered rare.
+		 */
+		if (pci_match_id(bridge_devids, bridge)) {
+			if (pcie_get_readrq(pdev) > 256) {
+				pci_info(pdev, "limiting MRRS to 256\n");
+				pcie_set_readrq(pdev, 256);
+			}
+			break;
+		}
+	}
+}
+DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, loongson_firmware_mrrs_quirk);
+#endif
+
 static void loongson_pci_pin_quirk(struct pci_dev *pdev)
 {
 	pdev->pin = 1 + (PCI_FUNC(pdev->devfn) & 3);