Re: [PATCH] PCI: spacemit: Ignore PERST# bit for controllers

From: "Troy Mitchell" <troy.mitchell@linux.spacemit.com>
To: "Ali Tariq" <alitariq45892@gmail.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
	"Manivannan Sadhasivam" <mani@kernel.org>,
	linux-pci@vger.kernel.org
Cc: "Rob Herring" <robh@kernel.org>, "Yixun Lan" <dlan@kernel.org>,
	"Troy Mitchell" <troy.mitchell@linux.spacemit.com>,
	"Ping-Ke Shih" <pkshih@realtek.com>,
	"Anirudh Srinivasan" <asrinivasan@oss.tenstorrent.com>,
	"Alex Elder" <elder@riscstar.com>,
	"Vladimir Oltean" <vladimir.oltean@nxp.com>,
	"Uwe Kleine-König (The Capable Hub)"
	<u.kleine-koenig@baylibre.com>,
	"Pengpeng Hou" <pengpeng@iscas.ac.cn>,
	"open list:RISC-V SPACEMIT SoC Support"
	<linux-riscv@lists.infradead.org>,
	"open list:RISC-V SPACEMIT SoC Support"
	<spacemit@lists.linux.dev>,
	"open list" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] PCI: spacemit: Ignore PERST# bit for controllers
Date: Wed, 04 Nov 2026 14:14:14 +0000	[thread overview]
Message-ID: <DMMHM7OIO97H.2SHNC575QC4PY@linux.spacemit.com> (raw)
In-Reply-To: <20261104140750.761330-1-alitariq45892@gmail.com>

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On Wed Nov 4, 2026 at 2:07 PM GMT, Ali Tariq wrote:
> The k1_pcie_init() does not set PCIE_IGNORE_PERSTN bit of the
> control logic register, which causes controller to reset itself once
> PERST# signal is asserted even when acting as host.
> On Orange Pi RV2 (SpacemiT K1), this resets the controller and wipes
> the IDs. k1_pcie_deinit() leaves PERST# asserted, so when k1_pcie_init()
> runs again, its first DBI access hangs the CPU.
>
> Set PCIE_IGNORE_PERSTN bit of the control logic register of APMU
> in k1_pcie_init() before enabling resources so controllers
> dont end up resetting themselves when PERST# signal is asserted.
>
> Fixes: ff64e078e45f ("PCI: spacemit: Add SpacemiT PCIe host driver")
> Signed-off-by: Ali Tariq <alitariq45892@gmail.com>
> ---
> Hang log: https://kernelci.cloud-v.co/scheduler/job/420
> Fixed Log: https://kernelci.cloud-v.co/scheduler/job/430
> ---
>  drivers/pci/controller/dwc/pcie-spacemit-k1.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/drivers/pci/controller/dwc/pcie-spacemit-k1.c b/drivers/pci/controller/dwc/pcie-spacemit-k1.c
> index 92a71ea90ac3..af6028e8825a 100644
> --- a/drivers/pci/controller/dwc/pcie-spacemit-k1.c
> +++ b/drivers/pci/controller/dwc/pcie-spacemit-k1.c
> @@ -47,6 +47,7 @@
>  
>  #define PCIE_CONTROL_LOGIC			0x0004
>  #define PCIE_SOFT_RESET			BIT(0)
> +#define PCIE_IGNORE_PERSTN		BIT(2)	/* 1: ignore PERST# */
A similar but earlier patch can be found here [1]

Link: https://lore.kernel.org/all/20260924-spacemit-k1-pcie-fix-v1-1-002b5c1ba9fc@linux.spacemit.com/ [1]

-- 
Troy Mitchell


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