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Message-ID: <AM6PR04MB5781A68E3511D6ACCAA192E3844A0@AM6PR04MB5781.eurprd04.prod.outlook.com>
Date: Wed, 13 Mar 2019 14:51:48 +0000
From: "Z.q. Hou" <zhiqiang.hou@....com>
To: "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"bhelgaas@...gle.com" <bhelgaas@...gle.com>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"mark.rutland@....com" <mark.rutland@....com>,
"l.subrahmanya@...iveil.co.in" <l.subrahmanya@...iveil.co.in>,
"shawnguo@...nel.org" <shawnguo@...nel.org>,
Leo Li <leoyang.li@....com>,
"lorenzo.pieralisi@....com" <lorenzo.pieralisi@....com>,
"catalin.marinas@....com" <catalin.marinas@....com>,
"will.deacon@....com" <will.deacon@....com>
CC: Mingkai Hu <mingkai.hu@....com>,
"M.h. Lian" <minghuan.lian@....com>,
Xiaowei Bao <xiaowei.bao@....com>
Subject: RE: [PATCHv4 26/28] PCI: mobiveil: ls_pcie_g4: add Workaround for
A-011451
Hi All,
Please ignore this patch, rev1.0 will not be production.
Thanks,
Zhiqiang
> -----Original Message-----
> From: Z.q. Hou
> Sent: 2019年3月11日 17:34
> To: linux-pci@...r.kernel.org; linux-arm-kernel@...ts.infradead.org;
> devicetree@...r.kernel.org; linux-kernel@...r.kernel.org;
> bhelgaas@...gle.com; robh+dt@...nel.org; mark.rutland@....com;
> l.subrahmanya@...iveil.co.in; shawnguo@...nel.org; Leo Li
> <leoyang.li@....com>; lorenzo.pieralisi@....com;
> catalin.marinas@....com; will.deacon@....com
> Cc: Mingkai Hu <mingkai.hu@....com>; M.h. Lian
> <minghuan.lian@....com>; Xiaowei Bao <xiaowei.bao@....com>; Z.q. Hou
> <zhiqiang.hou@....com>
> Subject: [PATCHv4 26/28] PCI: mobiveil: ls_pcie_g4: add Workaround for
> A-011451
>
> From: Hou Zhiqiang <Zhiqiang.Hou@....com>
>
> When LX2 PCIe controller is sending multiple split completions and ACK
> latency expires indicating that ACK should be send at priority.
> But because of large number of split completions and FC update DLLP, the
> controller does not give priority to ACK transmission. This results into ACK
> latency timer timeout error at the link partner and the pending TLPs are
> replayed by the link partner again.
>
> Workaround:
> 1. Reduce the ACK latency timeout value to a very small value.
> 2. Restrict the number of completions from the LX2 PCIe controller
> to 1, by changing the Max Read Request Size (MRRS) of link partner
> to the same value as Max Packet size (MPS).
>
> This patch implemented part 1, the part 2 can be set by kernel parameter
> 'pci=pcie_bus_perf'
>
> This ERRATA is only for LX2160A Rev1.0, and it will be fixed in Rev2.0.
>
> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@....com>
> ---
> V4:
> - no change
>
> .../pci/controller/mobiveil/pci-layerscape-gen4.c | 15 +++++++++++++++
> drivers/pci/controller/mobiveil/pcie-mobiveil.h | 4 ++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> index d2c5dbbd5e3c..20ce146788ca 100644
> --- a/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> +++ b/drivers/pci/controller/mobiveil/pci-layerscape-gen4.c
> @@ -82,12 +82,27 @@ static bool ls_pcie_g4_is_bridge(struct ls_pcie_g4
> *pcie)
> return header_type == PCI_HEADER_TYPE_BRIDGE; }
>
> +static void workaround_A011451(struct ls_pcie_g4 *pcie) {
> + struct mobiveil_pcie *mv_pci = pcie->pci;
> + u32 val;
> +
> + /* Set ACK latency timeout */
> + val = csr_readl(mv_pci, GPEX_ACK_REPLAY_TO);
> + val &= ~(ACK_LAT_TO_VAL_MASK << ACK_LAT_TO_VAL_SHIFT);
> + val |= (4 << ACK_LAT_TO_VAL_SHIFT);
> + csr_writel(mv_pci, val, GPEX_ACK_REPLAY_TO); }
> +
> static int ls_pcie_g4_host_init(struct mobiveil_pcie *pci) {
> struct ls_pcie_g4 *pcie = to_ls_pcie_g4(pci);
>
> pcie->rev = csr_readb(pci, PCI_REVISION_ID);
>
> + if (pcie->rev == REV_1_0)
> + workaround_A011451(pcie);
> +
> return 0;
> }
>
> diff --git a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
> b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
> index ab43de5e4b2b..f0e2e4ae09b5 100644
> --- a/drivers/pci/controller/mobiveil/pcie-mobiveil.h
> +++ b/drivers/pci/controller/mobiveil/pcie-mobiveil.h
> @@ -85,6 +85,10 @@
> #define PAB_AXI_AMAP_PEX_WIN_H(win) PAB_REG_ADDR(0x0bac,
> win)
> #define PAB_INTP_AXI_PIO_CLASS 0x474
>
> +#define GPEX_ACK_REPLAY_TO 0x438
> +#define ACK_LAT_TO_VAL_MASK 0x1fff
> +#define ACK_LAT_TO_VAL_SHIFT 0
> +
> #define PAB_PEX_AMAP_CTRL(win) PAB_REG_ADDR(0x4ba0, win)
> #define AMAP_CTRL_EN_SHIFT 0
> #define AMAP_CTRL_TYPE_SHIFT 1
> --
> 2.17.1
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