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PCI: imx6: Do not switch speed if Gen2 is disabled

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Save a bit of time and avoid going through link speed change procedure in
configuration where link max speed is limited to Gen1 in DT.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Cc: yurovsky@gmail.com
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Dong Aisheng <dongas86@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
This commit is contained in:
Andrey Smirnov 2017-03-28 08:42:52 -07:00 committed by Bjorn Helgaas
parent e6dcd87fff
commit 93b226f9c6
1 changed files with 26 additions and 26 deletions
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52
drivers/pci/dwc/pci-imx6.c
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@ -533,40 +533,40 @@ static int imx6_pcie_establish_link(struct imx6_pcie *imx6_pcie)
tmp &= ~PCIE_RC_LCR_MAX_LINK_SPEEDS_MASK;
tmp |= PCIE_RC_LCR_MAX_LINK_SPEEDS_GEN2;
dw_pcie_writel_dbi(pci, PCIE_RC_LCR, tmp);
} else {
dev_info(dev, "Link: Gen2 disabled\n");
}
/*
* Start Directed Speed Change so the best possible speed both link
* partners support can be negotiated.
*/
tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
tmp |= PORT_LOGIC_SPEED_CHANGE;
dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);
if (imx6_pcie->variant != IMX7D) {
/*
* On i.MX7, DIRECT_SPEED_CHANGE behaves differently
* from i.MX6 family when no link speed transition
* occurs and we go Gen1 -> yep, Gen1. The difference
* is that, in such case, it will not be cleared by HW
* which will cause the following code to report false
* failure.
* Start Directed Speed Change so the best possible
* speed both link partners support can be negotiated.
*/
tmp = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
tmp |= PORT_LOGIC_SPEED_CHANGE;
dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, tmp);
ret = imx6_pcie_wait_for_speed_change(imx6_pcie);
if (imx6_pcie->variant != IMX7D) {
/*
* On i.MX7, DIRECT_SPEED_CHANGE behaves differently
* from i.MX6 family when no link speed transition
* occurs and we go Gen1 -> yep, Gen1. The difference
* is that, in such case, it will not be cleared by HW
* which will cause the following code to report false
* failure.
*/
ret = imx6_pcie_wait_for_speed_change(imx6_pcie);
if (ret) {
dev_err(dev, "Failed to bring link up!\n");
goto err_reset_phy;
}
}
/* Make sure link training is finished as well! */
ret = imx6_pcie_wait_for_link(imx6_pcie);
if (ret) {
dev_err(dev, "Failed to bring link up!\n");
goto err_reset_phy;
}
}
/* Make sure link training is finished as well! */
ret = imx6_pcie_wait_for_link(imx6_pcie);
if (ret) {
dev_err(dev, "Failed to bring link up!\n");
goto err_reset_phy;
} else {
dev_info(dev, "Link: Gen2 disabled\n");
}
tmp = dw_pcie_readl_dbi(pci, PCIE_RC_LCSR);