diff options
| author | Christian Bruel <christian.bruel@foss.st.com> | 2025-11-14 08:45:52 +0100 |
|---|---|---|
| committer | Bjorn Helgaas <bhelgaas@google.com> | 2025-11-17 14:32:51 -0600 |
| commit | fa81d6099007728cae39c6f937d83903bbddab5e (patch) | |
| tree | a90d5bbd392d9a2b05dd44b4b017a4b9cdda11b3 /drivers/pci/controller/dwc | |
| parent | 3a8660878839faadb4f1a6dd72c3179c1df56787 (diff) | |
PCI: stm32: Fix LTSSM EP race with start link
If the host has deasserted PERST# and started link training before the link
is started on EP side, enabling LTSSM before the endpoint registers are
initialized in the perst_irq handler results in probing incorrect values.
Thus, wait for the PERST# level-triggered interrupt to start link training
at the end of initialization and cleanup the stm32_pcie_[start stop]_link
functions.
Fixes: 151f3d29baf4 ("PCI: stm32-ep: Add PCIe Endpoint support for STM32MP25")
Signed-off-by: Christian Bruel <christian.bruel@foss.st.com>
[mani: added fixes tag]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: wrap line]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20251114-perst_ep-v1-1-e7976317a890@foss.st.com
Diffstat (limited to 'drivers/pci/controller/dwc')
| -rw-r--r-- | drivers/pci/controller/dwc/pcie-stm32-ep.c | 39 |
1 files changed, 8 insertions, 31 deletions
diff --git a/drivers/pci/controller/dwc/pcie-stm32-ep.c b/drivers/pci/controller/dwc/pcie-stm32-ep.c index 3400c7cd2d88..faa6433a784f 100644 --- a/drivers/pci/controller/dwc/pcie-stm32-ep.c +++ b/drivers/pci/controller/dwc/pcie-stm32-ep.c @@ -37,36 +37,9 @@ static void stm32_pcie_ep_init(struct dw_pcie_ep *ep) dw_pcie_ep_reset_bar(pci, bar); } -static int stm32_pcie_enable_link(struct dw_pcie *pci) -{ - struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci); - - regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR, - STM32MP25_PCIECR_LTSSM_EN, - STM32MP25_PCIECR_LTSSM_EN); - - return dw_pcie_wait_for_link(pci); -} - -static void stm32_pcie_disable_link(struct dw_pcie *pci) -{ - struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci); - - regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR, STM32MP25_PCIECR_LTSSM_EN, 0); -} - static int stm32_pcie_start_link(struct dw_pcie *pci) { struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci); - int ret; - - dev_dbg(pci->dev, "Enable link\n"); - - ret = stm32_pcie_enable_link(pci); - if (ret) { - dev_err(pci->dev, "PCIe cannot establish link: %d\n", ret); - return ret; - } enable_irq(stm32_pcie->perst_irq); @@ -77,11 +50,7 @@ static void stm32_pcie_stop_link(struct dw_pcie *pci) { struct stm32_pcie *stm32_pcie = to_stm32_pcie(pci); - dev_dbg(pci->dev, "Disable link\n"); - disable_irq(stm32_pcie->perst_irq); - - stm32_pcie_disable_link(pci); } static int stm32_pcie_raise_irq(struct dw_pcie_ep *ep, u8 func_no, @@ -152,6 +121,9 @@ static void stm32_pcie_perst_assert(struct dw_pcie *pci) dev_dbg(dev, "PERST asserted by host\n"); + regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR, + STM32MP25_PCIECR_LTSSM_EN, 0); + pci_epc_deinit_notify(ep->epc); stm32_pcie_disable_resources(stm32_pcie); @@ -192,6 +164,11 @@ static void stm32_pcie_perst_deassert(struct dw_pcie *pci) pci_epc_init_notify(ep->epc); + /* Enable link training */ + regmap_update_bits(stm32_pcie->regmap, SYSCFG_PCIECR, + STM32MP25_PCIECR_LTSSM_EN, + STM32MP25_PCIECR_LTSSM_EN); + return; err_disable_resources: |