Commit b9ac0f9dc8ea ("PCI: dwc: Move dw_pcie_setup_rc() to DWC common
code") broke enumeration of downstream devices on Tegra:
In non working case (next-20201211):
0001:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad2 (rev a1)
0001:01:00.0 SATA controller: Marvell Technology Group Ltd. Device 9171 (rev 13)
0005:00:00.0 PCI bridge: NVIDIA Corporation Device 1ad0 (rev a1)
In working case (v5.10-rc7):
0001:00:00.0 PCI bridge: Molex Incorporated Device 1ad2 (rev a1)
0001:01:00.0 SATA controller: Marvell Technology Group Ltd. Device 9171 (rev 13)
0005:00:00.0 PCI bridge: Molex Incorporated Device 1ad0 (rev a1)
0005:01:00.0 PCI bridge: PLX Technology, Inc. Device 3380 (rev ab)
0005:02:02.0 PCI bridge: PLX Technology, Inc. Device 3380 (rev ab)
0005:03:00.0 USB controller: PLX Technology, Inc. Device 3380 (rev ab)
The problem seems to be dw_pcie_setup_rc() is now called twice before
and after the link up handling. The fix is to move Tegra's link up
handling to .start_link() function like other DWC drivers. Tegra is a
bit more complicated than others as it re-inits the whole DWC controller
to retry the link. With this, the initialization ordering is restored to
match the prior sequence.
Fixes: b9ac0f9dc8ea ("PCI: dwc: Move dw_pcie_setup_rc() to DWC common code")
Reported-by: Mian Yousaf Kaukab <ykaukab@xxxxxxx>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Thierry Reding <thierry.reding@xxxxxxxxx>
Cc: Jonathan Hunter <jonathanh@xxxxxxxxxx>
Cc: Vidya Sagar <vidyas@xxxxxxxxxx>
Cc: linux-tegra@xxxxxxxxxxxxxxx
Tested-by: Mian Yousaf Kaukab <ykaukab@xxxxxxx>
Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
---
Mian, One addition to what you tested. The resume hook also needs to
call start_link and that part was moved out of host_init.
Also, I noticed it looks like suspend/resume is broken for endpoint mode
as the hooks are for host mode only.
Bjorn, please apply this for v5.11.
---
drivers/pci/controller/dwc/pcie-tegra194.c | 55 ++++++++++++----------
1 file changed, 29 insertions(+), 26 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 5597b2a49598..6fa216e52d14 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -853,12 +853,14 @@ static void config_gen3_gen4_eq_presets(struct tegra_pcie_dw *pcie)
dw_pcie_writel_dbi(pci, GEN3_RELATED_OFF, val);
}
-static void tegra_pcie_prepare_host(struct pcie_port *pp)
+static int tegra_pcie_dw_host_init(struct pcie_port *pp)
{
struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
u32 val;
+ pp->bridge->ops = &tegra_pci_ops;
+
if (!pcie->pcie_cap_base)
pcie->pcie_cap_base = dw_pcie_find_capability(&pcie->pci,
PCI_CAP_ID_EXP);
@@ -907,10 +909,24 @@ static void tegra_pcie_prepare_host(struct pcie_port *pp)
dw_pcie_writel_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF, val);
}
- dw_pcie_setup_rc(pp);
-
clk_set_rate(pcie->core_clk, GEN4_CORE_CLK_FREQ);
+ return 0;
+}
+
+static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
+{
+ u32 val, offset, speed, tmp;
+ struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
+ struct pcie_port *pp = &pci->pp;
+ bool retry = true;
+
+ if (pcie->mode == DW_PCIE_EP_TYPE) {
+ enable_irq(pcie->pex_rst_irq);
+ return 0;
+ }
+
+retry_link:
/* Assert RST */
val = appl_readl(pcie, APPL_PINMUX);
val &= ~APPL_PINMUX_PEX_RST;
@@ -929,19 +945,10 @@ static void tegra_pcie_prepare_host(struct pcie_port *pp)
appl_writel(pcie, val, APPL_PINMUX);
msleep(100);
-}
-
-static int tegra_pcie_dw_host_init(struct pcie_port *pp)
-{
- struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
- struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
- u32 val, tmp, offset, speed;
-
- pp->bridge->ops = &tegra_pci_ops;
-
- tegra_pcie_prepare_host(pp);
if (dw_pcie_wait_for_link(pci)) {
+ if (!retry)
+ return 0;
/*
* There are some endpoints which can't get the link up if
* root port has Data Link Feature (DLF) enabled.
@@ -975,10 +982,11 @@ static int tegra_pcie_dw_host_init(struct pcie_port *pp)
val &= ~PCI_DLF_EXCHANGE_ENABLE;
dw_pcie_writel_dbi(pci, offset, val);
- tegra_pcie_prepare_host(pp);
+ tegra_pcie_dw_host_init(pp);
+ dw_pcie_setup_rc(pp);
- if (dw_pcie_wait_for_link(pci))
- return 0;
+ retry = false;
+ goto retry_link;
}
speed = dw_pcie_readw_dbi(pci, pcie->pcie_cap_base + PCI_EXP_LNKSTA) &
@@ -998,15 +1006,6 @@ static int tegra_pcie_dw_link_up(struct dw_pcie *pci)
return !!(val & PCI_EXP_LNKSTA_DLLLA);
}
-static int tegra_pcie_dw_start_link(struct dw_pcie *pci)
-{
- struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
-
- enable_irq(pcie->pex_rst_irq);
-
- return 0;
-}
-
static void tegra_pcie_dw_stop_link(struct dw_pcie *pci)
{
struct tegra_pcie_dw *pcie = to_tegra_pcie(pci);
@@ -2215,6 +2214,10 @@ static int tegra_pcie_dw_resume_noirq(struct device *dev)
goto fail_host_init;
}
+ ret = tegra_pcie_dw_start_link(&pcie->pci);
+ if (ret < 0)
+ goto fail_host_init;
+
/* Restore MSI interrupt vector */
dw_pcie_writel_dbi(&pcie->pci, PORT_LOGIC_MSI_CTRL_INT_0_EN,
pcie->msi_ctrl_int);
--
2.25.1
