ath11k: pci: disable ASPM L0sLs before downloading firmware

Sometimes QCA6390 doesn't switch to amss state as device enters
L1ss state, so disable L0sL1s during firmware downloading.
Driver recovers the ASPM to default value in start callback
or powerdown callback.

Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1
Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1608218530-15426-1-git-send-email-kvalo@codeaurora.org

drivers/net/wireless/ath/ath11k/pci.c

@@ -886,6 +886,32 @@ static void ath11k_pci_free_region(struct ath11k_pci *ab_pci)
 		pci_disable_device(pci_dev);
 }
 
+static void ath11k_pci_aspm_disable(struct ath11k_pci *ab_pci)
+{
+	struct ath11k_base *ab = ab_pci->ab;
+
+	pcie_capability_read_word(ab_pci->pdev, PCI_EXP_LNKCTL,
+				  &ab_pci->link_ctl);
+
+	ath11k_dbg(ab, ATH11K_DBG_PCI, "pci link_ctl 0x%04x L0s %d L1 %d\n",
+		   ab_pci->link_ctl,
+		   u16_get_bits(ab_pci->link_ctl, PCI_EXP_LNKCTL_ASPM_L0S),
+		   u16_get_bits(ab_pci->link_ctl, PCI_EXP_LNKCTL_ASPM_L1));
+
+	/* disable L0s and L1 */
+	pcie_capability_write_word(ab_pci->pdev, PCI_EXP_LNKCTL,
+				   ab_pci->link_ctl & ~PCI_EXP_LNKCTL_ASPMC);
+
+	set_bit(ATH11K_PCI_ASPM_RESTORE, &ab_pci->flags);
+}
+
+static void ath11k_pci_aspm_restore(struct ath11k_pci *ab_pci)
+{
+	if (test_and_clear_bit(ATH11K_PCI_ASPM_RESTORE, &ab_pci->flags))
+		pcie_capability_write_word(ab_pci->pdev, PCI_EXP_LNKCTL,
+					   ab_pci->link_ctl);
+}
+
 static int ath11k_pci_power_up(struct ath11k_base *ab)
 {
 	struct ath11k_pci *ab_pci = ath11k_pci_priv(ab);
@@ -895,6 +921,11 @@ static int ath11k_pci_power_up(struct ath11k_base *ab)
 	clear_bit(ATH11K_PCI_FLAG_INIT_DONE, &ab_pci->flags);
 	ath11k_pci_sw_reset(ab_pci->ab, true);
 
+	/* Disable ASPM during firmware download due to problems switching
+	 * to AMSS state.
+	 */
+	ath11k_pci_aspm_disable(ab_pci);
+
 	ret = ath11k_mhi_start(ab_pci);
 	if (ret) {
 		ath11k_err(ab, "failed to start mhi: %d\n", ret);
@@ -908,6 +939,9 @@ static void ath11k_pci_power_down(struct ath11k_base *ab)
 {
 	struct ath11k_pci *ab_pci = ath11k_pci_priv(ab);
 
+	/* restore aspm in case firmware bootup fails */
+	ath11k_pci_aspm_restore(ab_pci);
+
 	ath11k_pci_force_wake(ab_pci->ab);
 	ath11k_mhi_stop(ab_pci);
 	clear_bit(ATH11K_PCI_FLAG_INIT_DONE, &ab_pci->flags);
@@ -965,6 +999,8 @@ static int ath11k_pci_start(struct ath11k_base *ab)
 
 	set_bit(ATH11K_PCI_FLAG_INIT_DONE, &ab_pci->flags);
 
+	ath11k_pci_aspm_restore(ab_pci);
+
 	ath11k_pci_ce_irqs_enable(ab);
 	ath11k_ce_rx_post_buf(ab);
 

drivers/net/wireless/ath/ath11k/pci.h

@@ -63,6 +63,7 @@ struct ath11k_msi_config {
 enum ath11k_pci_flags {
 	ATH11K_PCI_FLAG_INIT_DONE,
 	ATH11K_PCI_FLAG_IS_MSI_64,
+	ATH11K_PCI_ASPM_RESTORE,
 };
 
 struct ath11k_pci {
@@ -80,6 +81,7 @@ struct ath11k_pci {
 
 	/* enum ath11k_pci_flags */
 	unsigned long flags;
+	u16 link_ctl;
 };
 
 static inline struct ath11k_pci *ath11k_pci_priv(struct ath11k_base *ab)