From: Bjorn Helgaas <helgaas@kernel.org>
To: Jim Quinlan <james.quinlan@broadcom.com>
Cc: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Rob Herring <robh@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Florian Fainelli <f.fainelli@gmail.com>,
"maintainer:BROADCOM BCM7XXX ARM ARCHITECTURE"
<bcm-kernel-feedback-list@broadcom.com>,
"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE"
<linux-rpi-kernel@lists.infradead.org>,
"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE"
<linux-arm-kernel@lists.infradead.org>,
"open list:PCI NATIVE HOST BRIDGE AND ENDPOINT DRIVERS"
<linux-pci@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/5] PCI: brcmstb: enable CRS
Date: Thu, 30 Apr 2020 15:32:52 -0500 [thread overview]
Message-ID: <20200430203252.GA62266@bjorn-Precision-5520> (raw)
In-Reply-To: <20200430185522.4116-3-james.quinlan@broadcom.com>
On Thu, Apr 30, 2020 at 02:55:20PM -0400, Jim Quinlan wrote:
> From: Jim Quinlan <jquinlan@broadcom.com>
>
> Configuration Retry Request Status is off by default on this
> PCIe controller. Turn it on.
Are you talking about CRS itself, i.e., the ability of a Root Port to
deal with Completions with Configuration Retry Request Status? That
really shouldn't be switchable in the hardware since it's a required
feature for all PCIe devices.
Or are you talking about CRS Software Visibility, which is controlled
by a bit in the PCIe Root Control register? That *should* be managed
by the PCI core in pci_enable_crs(). Does that generic method of
controlling it not work for this device?
It looks like maybe the latter, since the generic:
#define PCI_EXP_RTCTL_CRSSVE 0x0010
matches your new PCIE_RC_CFG_PCIE_ROOT_CAP_CONTROL_RC_CRS_EN_MASK.
If pci_enable_crs() doesn't work on this device, it sounds like a
hardware defect that we need to work around, but I'm not sure that
just enabling it unconditionally here is the right thing.
> Signed-off-by: Jim Quinlan <jquinlan@broadcom.com>
> ---
> drivers/pci/controller/pcie-brcmstb.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> index 5b0dec5971b8..2bc913c0262c 100644
> --- a/drivers/pci/controller/pcie-brcmstb.c
> +++ b/drivers/pci/controller/pcie-brcmstb.c
> @@ -34,6 +34,9 @@
> #define BRCM_PCIE_CAP_REGS 0x00ac
>
> /* Broadcom STB PCIe Register Offsets */
> +#define PCIE_RC_CFG_PCIE_ROOT_CAP_CONTROL 0x00c8
> +#define PCIE_RC_CFG_PCIE_ROOT_CAP_CONTROL_RC_CRS_EN_MASK 0x10
> +
> #define PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1 0x0188
> #define PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1_ENDIAN_MODE_BAR2_MASK 0xc
> #define PCIE_RC_CFG_VENDOR_SPCIFIC_REG1_LITTLE_ENDIAN 0x0
> @@ -827,6 +830,12 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> pci_speed_string(pcie_link_speed[cls]), nlw,
> ssc_good ? "(SSC)" : "(!SSC)");
>
> + /* Enable configuration request retry (CRS) */
> + tmp = readl(base + PCIE_RC_CFG_PCIE_ROOT_CAP_CONTROL);
> + u32p_replace_bits(&tmp, 1,
> + PCIE_RC_CFG_PCIE_ROOT_CAP_CONTROL_RC_CRS_EN_MASK);
> + writel(tmp, base + PCIE_RC_CFG_PCIE_ROOT_CAP_CONTROL);
> +
> /* PCIe->SCB endian mode for BAR */
> tmp = readl(base + PCIE_RC_CFG_VENDOR_VENDOR_SPECIFIC_REG1);
> u32p_replace_bits(&tmp, PCIE_RC_CFG_VENDOR_SPCIFIC_REG1_LITTLE_ENDIAN,
> --
> 2.17.1
>
next prev parent reply other threads:[~2020-04-30 20:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 18:55 [PATCH 1/5] PCI: brcmstb: don't clk_put() a managed clock Jim Quinlan
2020-04-30 18:55 ` [PATCH 2/5] PCI: brcmstb: fix window register offset from 4 to 8 Jim Quinlan
2020-04-30 19:07 ` Florian Fainelli
2020-04-30 20:43 ` Bjorn Helgaas
2020-04-30 18:55 ` [PATCH 3/5] PCI: brcmstb: enable CRS Jim Quinlan
2020-04-30 19:19 ` Florian Fainelli
2020-04-30 20:32 ` Bjorn Helgaas [this message]
2020-04-30 21:00 ` Jim Quinlan
2020-04-30 18:55 ` [PATCH 4/5] dt-bindings: PCI: brcmstb: New prop 'brcm,aspm-en-l0s' Jim Quinlan
2020-04-30 19:20 ` Florian Fainelli
2020-04-30 18:55 ` [PATCH 5/5] PCI: brcmstb: disable L0s component of ASPM by default Jim Quinlan
2020-04-30 19:21 ` Florian Fainelli
2020-04-30 20:40 ` Bjorn Helgaas
2020-04-30 21:17 ` Jim Quinlan
2020-04-30 19:05 ` [PATCH 1/5] PCI: brcmstb: don't clk_put() a managed clock Florian Fainelli
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