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PCI: dwc: Group DBI registers writes requiring unlocking 

Some of DesignWare core's DBI registers (a.k.a configuration space
registers) are write-protected with a lock without enabling which they
are read-only by default.

These write-protected registers are implementation specific. Tegra194's
BAR-0 register which is at offset 0x10 in the configuration space is an
example. Current implementation in dw_pcie_setup_rc() API attempts to
unlock those write-protected registers whenever they are updated and
lock them back again for writing.

Group all write-protected registers writes so that locking and unlocking
is performed once to avoid bloating the code with multiple unlock/lock
sequences for all those write-protected registers.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Acked-by: Jingoo Han <jingoohan1@gmail.com>
This commit is contained in:
Vidya Sagar 2019-08-13 17:06:17 +05:30 committed by Lorenzo Pieralisi
parent 8c7e96d3fe
commit 3924bc2fd1
1 changed files with 8 additions and 6 deletions
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14
drivers/pci/controller/dwc/pcie-designware-host.c
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@ -628,6 +628,12 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
u32 val, ctrl, num_ctrls;
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
/*
* Enable DBI read-only registers for writing/updating configuration.
* Write permission gets disabled towards the end of this function.
*/
dw_pcie_dbi_ro_wr_en(pci);
dw_pcie_setup(pci);
if (!pp->ops->msi_host_init) {
@ -650,12 +656,10 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_1, 0x00000000);
/* Setup interrupt pins */
dw_pcie_dbi_ro_wr_en(pci);
val = dw_pcie_readl_dbi(pci, PCI_INTERRUPT_LINE);
val &= 0xffff00ff;
val |= 0x00000100;
dw_pcie_writel_dbi(pci, PCI_INTERRUPT_LINE, val);
dw_pcie_dbi_ro_wr_dis(pci);
/* Setup bus numbers */
val = dw_pcie_readl_dbi(pci, PCI_PRIMARY_BUS);
@ -687,15 +691,13 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
dw_pcie_wr_own_conf(pp, PCI_BASE_ADDRESS_0, 4, 0);
/* Enable write permission for the DBI read-only register */
dw_pcie_dbi_ro_wr_en(pci);
/* Program correct class for RC */
dw_pcie_wr_own_conf(pp, PCI_CLASS_DEVICE, 2, PCI_CLASS_BRIDGE_PCI);
/* Better disable write permission right after the update */
dw_pcie_dbi_ro_wr_dis(pci);
dw_pcie_rd_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, &val);
val |= PORT_LOGIC_SPEED_CHANGE;
dw_pcie_wr_own_conf(pp, PCIE_LINK_WIDTH_SPEED_CONTROL, 4, val);
dw_pcie_dbi_ro_wr_dis(pci);
}
EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);