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PCI: dwc: Always cache the maximum link speed value in dw_pcie::max_link_speed

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Currently, the dw_pcie::max_link_speed has a valid value only if the
controller driver restricts the maximum link speed in the driver or if
the platform does so in the devicetree using the 'max-link-speed'
property.

But having the maximum supported link speed of the platform would be
helpful for the vendor drivers to configure any link specific settings.

So in the case of non-valid value in dw_pcie::max_link_speed, just cache
the hardware default value from Link Capability register.

While at it, remove the 'max_link_speed' argument to the
dw_pcie_link_set_max_speed() function since the value can be
retrieved within the function.

Link: https://lore.kernel.org/linux-pci/20240911-pci-qcom-gen4-stability-v7-2-743f5c1fd027@linaro.org
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
This commit is contained in:
Manivannan Sadhasivam 2024-09-11 20:56:27 +05:30 committed by Krzysztof Wilczyński
parent 2cebf68a24
commit 19a69cbd9d
No known key found for this signature in database
GPG Key ID: 7C64768D3DE334E7
1 changed files with 14 additions and 4 deletions
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18
drivers/pci/controller/dwc/pcie-designware.c
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@ -689,16 +689,27 @@ void dw_pcie_upconfig_setup(struct dw_pcie *pci)
}
EXPORT_SYMBOL_GPL(dw_pcie_upconfig_setup);
static void dw_pcie_link_set_max_speed(struct dw_pcie *pci, u32 max_link_speed)
static void dw_pcie_link_set_max_speed(struct dw_pcie *pci)
{
u32 cap, ctrl2, link_speed;
u8 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP);
cap = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCAP);
/*
* Even if the platform doesn't want to limit the maximum link speed,
* just cache the hardware default value so that the vendor drivers can
* use it to do any link specific configuration.
*/
if (pci->max_link_speed < 1) {
pci->max_link_speed = FIELD_GET(PCI_EXP_LNKCAP_SLS, cap);
return;
}
ctrl2 = dw_pcie_readl_dbi(pci, offset + PCI_EXP_LNKCTL2);
ctrl2 &= ~PCI_EXP_LNKCTL2_TLS;
switch (pcie_link_speed[max_link_speed]) {
switch (pcie_link_speed[pci->max_link_speed]) {
case PCIE_SPEED_2_5GT:
link_speed = PCI_EXP_LNKCTL2_TLS_2_5GT;
break;
@ -1060,8 +1071,7 @@ void dw_pcie_setup(struct dw_pcie *pci)
{
u32 val;
if (pci->max_link_speed > 0)
dw_pcie_link_set_max_speed(pci, pci->max_link_speed);
dw_pcie_link_set_max_speed(pci);
/* Configure Gen1 N_FTS */
if (pci->n_fts[0]) {