Patch "wifi: rtw89: pci: early chips only enable 36-bit DMA on specific PCI hosts" has been added to the 6.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    wifi: rtw89: pci: early chips only enable 36-bit DMA on specific PCI hosts

to the 6.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wifi-rtw89-pci-early-chips-only-enable-36-bit-dma-on.patch
and it can be found in the queue-6.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit dadb29fa3c79754f559b7d7ad70b0186fe5f7c21
Author: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
Date:   Tue Sep 24 10:16:33 2024 +0800

    wifi: rtw89: pci: early chips only enable 36-bit DMA on specific PCI hosts
    
    [ Upstream commit aa70ff0945fea2ed14046273609d04725f222616 ]
    
    The early chips including RTL8852A, RTL8851B, RTL8852B and RTL8852BT have
    interoperability problems of 36-bit DMA with some PCI hosts. Rollback
    to 32-bit DMA by default, and only enable 36-bit DMA for tested platforms.
    
    Since all Intel platforms we have can work correctly, add the vendor ID to
    white list. Otherwise, list vendor/device ID of bridge we have tested.
    
    Fixes: 1fd4b3fe52ef ("wifi: rtw89: pci: support 36-bit PCI DMA address")
    Reported-by: Marcel Weißenbach <mweissenbach@xxxxxxxxx>
    Closes: https://lore.kernel.org/linux-wireless/20240918073237.Horde.VLueh0_KaiDw-9asEEcdM84@xxxxxxxxx/T/#m07c5694df1acb173a42e1a0bab7ac22bd231a2b8
    Signed-off-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
    Tested-by: Marcel Weißenbach <mweissenbach@xxxxxxxxx>
    Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxx>
    Link: https://patch.msgid.link/20240924021633.19861-1-pkshih@xxxxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/wireless/realtek/rtw89/pci.c b/drivers/net/wireless/realtek/rtw89/pci.c
index 02afeb3acce46..5aef7fa378788 100644
--- a/drivers/net/wireless/realtek/rtw89/pci.c
+++ b/drivers/net/wireless/realtek/rtw89/pci.c
@@ -3026,24 +3026,54 @@ static void rtw89_pci_declaim_device(struct rtw89_dev *rtwdev,
 	pci_disable_device(pdev);
 }
 
-static void rtw89_pci_cfg_dac(struct rtw89_dev *rtwdev)
+static bool rtw89_pci_chip_is_manual_dac(struct rtw89_dev *rtwdev)
 {
-	struct rtw89_pci *rtwpci = (struct rtw89_pci *)rtwdev->priv;
 	const struct rtw89_chip_info *chip = rtwdev->chip;
 
-	if (!rtwpci->enable_dac)
-		return;
-
 	switch (chip->chip_id) {
 	case RTL8852A:
 	case RTL8852B:
 	case RTL8851B:
 	case RTL8852BT:
-		break;
+		return true;
 	default:
-		return;
+		return false;
+	}
+}
+
+static bool rtw89_pci_is_dac_compatible_bridge(struct rtw89_dev *rtwdev)
+{
+	struct rtw89_pci *rtwpci = (struct rtw89_pci *)rtwdev->priv;
+	struct pci_dev *bridge = pci_upstream_bridge(rtwpci->pdev);
+
+	if (!rtw89_pci_chip_is_manual_dac(rtwdev))
+		return true;
+
+	if (!bridge)
+		return false;
+
+	switch (bridge->vendor) {
+	case PCI_VENDOR_ID_INTEL:
+		return true;
+	case PCI_VENDOR_ID_ASMEDIA:
+		if (bridge->device == 0x2806)
+			return true;
+		break;
 	}
 
+	return false;
+}
+
+static void rtw89_pci_cfg_dac(struct rtw89_dev *rtwdev)
+{
+	struct rtw89_pci *rtwpci = (struct rtw89_pci *)rtwdev->priv;
+
+	if (!rtwpci->enable_dac)
+		return;
+
+	if (!rtw89_pci_chip_is_manual_dac(rtwdev))
+		return;
+
 	rtw89_pci_config_byte_set(rtwdev, RTW89_PCIE_L1_CTRL, RTW89_PCIE_BIT_EN_64BITS);
 }
 
@@ -3061,6 +3091,9 @@ static int rtw89_pci_setup_mapping(struct rtw89_dev *rtwdev,
 		goto err;
 	}
 
+	if (!rtw89_pci_is_dac_compatible_bridge(rtwdev))
+		goto no_dac;
+
 	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(36));
 	if (!ret) {
 		rtwpci->enable_dac = true;
@@ -3073,6 +3106,7 @@ static int rtw89_pci_setup_mapping(struct rtw89_dev *rtwdev,
 			goto err_release_regions;
 		}
 	}
+no_dac:
 
 	resource_len = pci_resource_len(pdev, bar_id);
 	rtwpci->mmap = pci_iomap(pdev, bar_id, resource_len);