[PATCH v1 3/3] PCI: brcmstb: Allow setting the completion timeout
Stefan Wahren
stefan.wahren at i2se.com
Thu Apr 6 08:59:18 PDT 2023
Hi Jim,
Am 06.04.23 um 14:46 schrieb Jim Quinlan:
> Since the STB PCIe HW will cause a CPU abort on a completion timeout abort,
> we might as well extend the timeout limit. Further, different devices and
> systems may requires a larger or smaller amount for L1SS exit.
>
> Signed-off-by: Jim Quinlan <jim2101024 at gmail.com>
> ---
> drivers/pci/controller/pcie-brcmstb.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index 129eee7bdbc1..92d78f4dfaae 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -1080,6 +1080,29 @@ static void brcm_config_clkreq(struct brcm_pcie *pcie)
> writel(clkreq_set, pcie->base + PCIE_MISC_HARD_PCIE_HARD_DEBUG);
> }
>
> +static void brcm_config_completion_timeout(struct brcm_pcie *pcie)
> +{
> + /* TIMEOUT register is two registers before RGR1_SW_INIT_1 */
> + const unsigned int REG_OFFSET = PCIE_RGR1_SW_INIT_1(pcie) - 8;
> + u32 timeout, timeout_msec = 1000;
> + u64 tmp64;
> + int ret;
> +
> + ret = of_property_read_u32(pcie->np, "brcm,completion-abort-msecs",
> + &timeout_msec);
> +
> + if (ret && ret != -EINVAL)
> + dev_err(pcie->dev, "bad 'brcm,completion-abort-msecs' prop\n");
i'm not sure about the error behavior. If we want to proceed with
defaults in such a case, i would make this a warning and mention the
used defaults.
> +
> + /* Each unit in timeout register is 1/216,000,000 seconds */
> + tmp64 = (u64)216000 * timeout_msec;
> +
> + /* Clamp the requested value before writing it */
> + timeout = tmp64 > 0xffffffff ? 0xffffffff : tmp64;
> + timeout = timeout < 0xffff ? 0xffff : timeout;
Personally i'm not a huge fan of silently clamping wrong DT values.
Best regards
> + writel(timeout, pcie->base + REG_OFFSET);
> +}
> +
> static int brcm_pcie_start_link(struct brcm_pcie *pcie)
> {
> struct device *dev = pcie->dev;
> @@ -1110,6 +1133,7 @@ static int brcm_pcie_start_link(struct brcm_pcie *pcie)
> return -ENODEV;
> }
>
> + brcm_config_completion_timeout(pcie);
> brcm_config_clkreq(pcie);
>
> if (pcie->gen)
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