6.15-stable review patch. If anyone has any objections, please let me know.
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From: Ping-Ke Shih pkshih@realtek.com
[ Upstream commit a70cf04b08f44f41bce14659aa7012674b15d9de ]
To support 36-bit DMA, configure chip proprietary bit via PCI config API or chip DBI interface. However, the PCI device mmap isn't set yet and the DBI is also inaccessible via mmap, so only if the bit can be accessible via PCI config API, chip can support 36-bit DMA. Otherwise, fallback to 32-bit DMA.
With NULL mmap address, kernel throws trace:
BUG: unable to handle page fault for address: 0000000000001090 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: Oops: 0002 [#1] PREEMPT SMP PTI CPU: 1 UID: 0 PID: 71 Comm: irq/26-pciehp Tainted: G OE 6.14.2-061402-generic #202504101348 Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE RIP: 0010:rtw89_pci_ops_write16+0x12/0x30 [rtw89_pci] RSP: 0018:ffffb0ffc0acf9d8 EFLAGS: 00010206 RAX: ffffffffc158f9c0 RBX: ffff94865e702020 RCX: 0000000000000000 RDX: 0000000000000718 RSI: 0000000000001090 RDI: ffff94865e702020 RBP: ffffb0ffc0acf9d8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000015 R13: 0000000000000719 R14: ffffb0ffc0acfa1f R15: ffffffffc1813060 FS: 0000000000000000(0000) GS:ffff9486f3480000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000001090 CR3: 0000000090440001 CR4: 00000000000626f0 Call Trace: <TASK> rtw89_pci_read_config_byte+0x6d/0x120 [rtw89_pci] rtw89_pci_cfg_dac+0x5b/0xb0 [rtw89_pci] rtw89_pci_probe+0xa96/0xbd0 [rtw89_pci] ? __pfx___device_attach_driver+0x10/0x10 ? __pfx___device_attach_driver+0x10/0x10 local_pci_probe+0x47/0xa0 pci_call_probe+0x5d/0x190 pci_device_probe+0xa7/0x160 really_probe+0xf9/0x370 ? pm_runtime_barrier+0x55/0xa0 __driver_probe_device+0x8c/0x140 driver_probe_device+0x24/0xd0 __device_attach_driver+0xcd/0x170 bus_for_each_drv+0x99/0x100 __device_attach+0xb4/0x1d0 device_attach+0x10/0x20 pci_bus_add_device+0x59/0x90 pci_bus_add_devices+0x31/0x80 pciehp_configure_device+0xaa/0x170 pciehp_enable_slot+0xd6/0x240 pciehp_handle_presence_or_link_change+0xf1/0x180 pciehp_ist+0x162/0x1c0 irq_thread_fn+0x24/0x70 irq_thread+0xef/0x1c0 ? __pfx_irq_thread_fn+0x10/0x10 ? __pfx_irq_thread_dtor+0x10/0x10 ? __pfx_irq_thread+0x10/0x10 kthread+0xfc/0x230 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x47/0x70 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK>
Fixes: 1fd4b3fe52ef ("wifi: rtw89: pci: support 36-bit PCI DMA address") Reported-by: Bitterblue Smith rtl8821cerfe2@gmail.com Closes: https://lore.kernel.org/linux-wireless/ccaf49b6-ff41-4917-90f1-f53cadaaa0da@... Closes: https://github.com/openwrt/openwrt/issues/17025 Signed-off-by: Ping-Ke Shih pkshih@realtek.com Link: https://patch.msgid.link/20250506015356.7995-1-pkshih@realtek.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/realtek/rtw89/pci.c | 34 ++++++++++++++++-------- 1 file changed, 23 insertions(+), 11 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtw89/pci.c b/drivers/net/wireless/realtek/rtw89/pci.c index c2fe5a898dc71..b5cdc18f802a9 100644 --- a/drivers/net/wireless/realtek/rtw89/pci.c +++ b/drivers/net/wireless/realtek/rtw89/pci.c @@ -3105,17 +3105,26 @@ static bool rtw89_pci_is_dac_compatible_bridge(struct rtw89_dev *rtwdev) return false; }
-static void rtw89_pci_cfg_dac(struct rtw89_dev *rtwdev) +static int rtw89_pci_cfg_dac(struct rtw89_dev *rtwdev, bool force) { struct rtw89_pci *rtwpci = (struct rtw89_pci *)rtwdev->priv; + struct pci_dev *pdev = rtwpci->pdev; + int ret; + u8 val;
- if (!rtwpci->enable_dac) - return; + if (!rtwpci->enable_dac && !force) + return 0;
if (!rtw89_pci_chip_is_manual_dac(rtwdev)) - return; + return 0;
- rtw89_pci_config_byte_set(rtwdev, RTW89_PCIE_L1_CTRL, RTW89_PCIE_BIT_EN_64BITS); + /* Configure DAC only via PCI config API, not DBI interfaces */ + ret = pci_read_config_byte(pdev, RTW89_PCIE_L1_CTRL, &val); + if (ret) + return ret; + + val |= RTW89_PCIE_BIT_EN_64BITS; + return pci_write_config_byte(pdev, RTW89_PCIE_L1_CTRL, val); }
static int rtw89_pci_setup_mapping(struct rtw89_dev *rtwdev, @@ -3133,13 +3142,16 @@ static int rtw89_pci_setup_mapping(struct rtw89_dev *rtwdev, }
if (!rtw89_pci_is_dac_compatible_bridge(rtwdev)) - goto no_dac; + goto try_dac_done;
ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(36)); if (!ret) { - rtwpci->enable_dac = true; - rtw89_pci_cfg_dac(rtwdev); - } else { + ret = rtw89_pci_cfg_dac(rtwdev, true); + if (!ret) { + rtwpci->enable_dac = true; + goto try_dac_done; + } + ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32)); if (ret) { rtw89_err(rtwdev, @@ -3147,7 +3159,7 @@ static int rtw89_pci_setup_mapping(struct rtw89_dev *rtwdev, goto err_release_regions; } } -no_dac: +try_dac_done:
resource_len = pci_resource_len(pdev, bar_id); rtwpci->mmap = pci_iomap(pdev, bar_id, resource_len); @@ -4302,7 +4314,7 @@ static void rtw89_pci_l2_hci_ldo(struct rtw89_dev *rtwdev) void rtw89_pci_basic_cfg(struct rtw89_dev *rtwdev, bool resume) { if (resume) - rtw89_pci_cfg_dac(rtwdev); + rtw89_pci_cfg_dac(rtwdev, false);
rtw89_pci_disable_eq(rtwdev); rtw89_pci_filter_out(rtwdev);