From: Vidya Sagar <vidyas@nvidia.com>
To: <lpieralisi@kernel.org>, <kw@linux.com>, <robh@kernel.org>,
<bhelgaas@google.com>, <thierry.reding@gmail.com>,
<jonathanh@nvidia.com>, <Sergey.Semin@baikalelectronics.ru>
Cc: <linux-pci@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <kthota@nvidia.com>,
<mmaddireddy@nvidia.com>, <vidyas@nvidia.com>,
<sagar.tv@gmail.com>
Subject: [PATCH V4] Revert "PCI: tegra194: Enable support for 256 Byte payload"
Date: Tue, 18 Jul 2023 08:22:21 +0530 [thread overview]
Message-ID: <20230718025221.4001329-1-vidyas@nvidia.com> (raw)
In-Reply-To: <20230619102604.3735001-1-vidyas@nvidia.com>
After commit 4fb8e46c1bc4 ("PCI: tegra194: Enable support for 256 Byte
payload"), we set MPS=256 for tegra194 Root Ports.
By default (CONFIG_PCIE_BUS_DEFAULT set and no "pci=pcie_bus_*"
parameter), Linux configures the MPS of every device to match the
upstream bridge, which is impossible if the Root Port has MPS=256
and a device only supports MPS=128.
This scenario results in uncorrectable Malformed TLP errors if the
Root Port sends TLPs with payloads larger than 128 bytes. These
errors can be avoided by using the "pci=pcie_bus_safe" parameter,
but it doesn't seem to be a good idea to always have this parameter
even for basic functionality to work.
Revert commit 4fb8e46c1bc4 ("PCI: tegra194: Enable support for 256 Byte
payload") so the Root Ports default to MPS=128, which all devices
support.
If peer-to-peer DMA is not required, one can use "pci=pcie_bus_perf"
to get the benefit of larger MPS settings.
[ rewrote commit message based on Bjorn's suggestion ]
Fixes: 4fb8e46c1bc4 ("PCI: tegra194: Enable support for 256 Byte payload")
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
---
V4:
* Rewrote commit message based on Bjorn's suggestion
V3:
* Fixed a build issue
V2:
* Addressed review comments from Bjorn
drivers/pci/controller/dwc/pcie-tegra194.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 4fdadc7b045f..a772faff14b5 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -900,11 +900,6 @@ static int tegra_pcie_dw_host_init(struct dw_pcie_rp *pp)
pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
PCI_CAP_ID_EXP);
- val_16 = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_DEVCTL);
- val_16 &= ~PCI_EXP_DEVCTL_PAYLOAD;
- val_16 |= PCI_EXP_DEVCTL_PAYLOAD_256B;
- dw_pcie_writew_dbi(pci, pcie->pcie_cap_base + PCI_EXP_DEVCTL, val_16);
-
val = dw_pcie_readl_dbi(pci, PCI_IO_BASE);
val &= ~(IO_BASE_IO_DECODE | IO_BASE_IO_DECODE_BIT8);
dw_pcie_writel_dbi(pci, PCI_IO_BASE, val);
@@ -1756,7 +1751,6 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
struct device *dev = pcie->dev;
u32 val;
int ret;
- u16 val_16;
if (pcie->ep_state == EP_STATE_ENABLED)
return;
@@ -1887,20 +1881,16 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
PCI_CAP_ID_EXP);
- val_16 = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_DEVCTL);
- val_16 &= ~PCI_EXP_DEVCTL_PAYLOAD;
- val_16 |= PCI_EXP_DEVCTL_PAYLOAD_256B;
- dw_pcie_writew_dbi(pci, pcie->pcie_cap_base + PCI_EXP_DEVCTL, val_16);
-
/* Clear Slot Clock Configuration bit if SRNS configuration */
if (pcie->enable_srns) {
+ u16 val_16;
+
val_16 = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base +
PCI_EXP_LNKSTA);
val_16 &= ~PCI_EXP_LNKSTA_SLC;
dw_pcie_writew_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA,
val_16);
}
-
clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
val = (ep->msi_mem_phys & MSIX_ADDR_MATCH_LOW_OFF_MASK);
--
2.25.1
next prev parent reply other threads:[~2023-07-18 2:52 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-08 9:36 [PATCH V1] Revert "PCI: tegra194: Enable support for 256 Byte payload" Vidya Sagar
2023-06-08 16:33 ` Bjorn Helgaas
2023-06-09 2:23 ` Vidya Sagar
2023-06-14 10:39 ` Jon Hunter
2023-06-19 1:42 ` [PATCH V2] " Vidya Sagar
2023-06-19 3:42 ` kernel test robot
2023-06-19 10:26 ` [PATCH V3] " Vidya Sagar
2023-06-27 10:48 ` Krzysztof Wilczyński
2023-07-13 21:39 ` Bjorn Helgaas
2023-07-18 2:33 ` Vidya Sagar
2023-07-18 11:09 ` Bjorn Helgaas
2023-07-19 11:01 ` Vidya Sagar
2023-07-19 14:57 ` Bjorn Helgaas
2023-07-18 2:52 ` Vidya Sagar [this message]
2023-07-21 8:23 ` [PATCH V4] " Jon Hunter
2023-07-21 10:35 ` Bjorn Helgaas
2023-07-28 12:44 ` Jon Hunter
2023-08-01 20:40 ` Bjorn Helgaas
2023-08-03 9:19 ` Vidya Sagar
2023-08-03 18:50 ` Krzysztof Wilczyński
2023-07-25 7:51 ` [PATCH V1] " Manivannan Sadhasivam
2023-07-25 8:19 ` Vidya Sagar
2023-07-25 8:30 ` Manivannan Sadhasivam
2023-07-25 9:21 ` Vidya Sagar
2023-07-25 10:03 ` Manivannan Sadhasivam
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230718025221.4001329-1-vidyas@nvidia.com \
--to=vidyas@nvidia.com \
--cc=Sergey.Semin@baikalelectronics.ru \
--cc=bhelgaas@google.com \
--cc=jonathanh@nvidia.com \
--cc=kthota@nvidia.com \
--cc=kw@linux.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=lpieralisi@kernel.org \
--cc=mmaddireddy@nvidia.com \
--cc=robh@kernel.org \
--cc=sagar.tv@gmail.com \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).