[PATCH] ath10k: Disable PCI PS for QCA988X and QCA99X0

[<akolli@qti.qualcomm.com>]

From: Anilkumar Kolli <akolli@qti.qualcomm.com>

This patch disables PCI PS for QCA988X and QCA99X0, Since PCI PS is
validated for QCA6174, let it be enabled only for QCA6174. It would be
better to execute PCI PS related functions only for the supported devices.

PCI time out issue is observed with QCA99X0 on x86 platform, We will
disable PCI PS for QCA988X and QCA99X0 until PCI PS is properly implemented.

Taking and releasing ps_lock is causing higher CPU consumption. Michal Kazior
suggested ps_lock overhead to be reworked so that ath10k_pci_wake/sleep
functions are called less often, i.e. move the powersave logic up (only during
irq handling, tx path, submitting fw commands).

Signed-off-by: Anilkumar Kolli <akolli@qti.qualcomm.com>
---

 drivers/net/wireless/ath/ath10k/pci.c | 83 ++++++++++++++++++++++++++++++++++-
 drivers/net/wireless/ath/ath10k/pci.h |  6 +++
 2 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
index 1046ab6..36b6f34 100644
--- a/drivers/net/wireless/ath/ath10k/pci.c
+++ b/drivers/net/wireless/ath/ath10k/pci.c
@@ -465,12 +465,53 @@ static int ath10k_pci_wake_wait(struct ath10k *ar)
 	return -ETIMEDOUT;
 }
 
+static int ath10k_pci_force_wake(struct ath10k *ar)
+{
+	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&ar_pci->ps_lock, flags);
+
+	if (!ar_pci->ps_awake) {
+		iowrite32(PCIE_SOC_WAKE_V_MASK,
+				ar_pci->mem + PCIE_LOCAL_BASE_ADDRESS +
+				PCIE_SOC_WAKE_ADDRESS);
+
+		ret = ath10k_pci_wake_wait(ar);
+		if (ret == 0)
+			ar_pci->ps_awake = true;
+	}
+
+	spin_unlock_irqrestore(&ar_pci->ps_lock, flags);
+
+	return ret;
+}
+
+static void ath10k_pci_force_sleep(struct ath10k *ar)
+{
+	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
+	unsigned long flags;
+
+	spin_lock_irqsave(&ar_pci->ps_lock, flags);
+
+	iowrite32(PCIE_SOC_WAKE_RESET,
+			ar_pci->mem + PCIE_LOCAL_BASE_ADDRESS +
+			PCIE_SOC_WAKE_ADDRESS);
+	ar_pci->ps_awake = false;
+
+	spin_unlock_irqrestore(&ar_pci->ps_lock, flags);
+}
+
 static int ath10k_pci_wake(struct ath10k *ar)
 {
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	unsigned long flags;
 	int ret = 0;
 
+	if (ar_pci->pci_ps == 0)
+		return ret;
+
 	spin_lock_irqsave(&ar_pci->ps_lock, flags);
 
 	ath10k_dbg(ar, ATH10K_DBG_PCI_PS, "pci ps wake refcount %lu awake %d\n",
@@ -502,6 +543,9 @@ static void ath10k_pci_sleep(struct ath10k *ar)
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	unsigned long flags;
 
+	if (ar_pci->pci_ps == 0)
+		return;
+
 	spin_lock_irqsave(&ar_pci->ps_lock, flags);
 
 	ath10k_dbg(ar, ATH10K_DBG_PCI_PS, "pci ps sleep refcount %lu awake %d\n",
@@ -544,6 +588,11 @@ static void ath10k_pci_sleep_sync(struct ath10k *ar)
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	unsigned long flags;
 
+	if (ar_pci->pci_ps == 0) {
+		ath10k_pci_force_sleep(ar);
+		return;
+	}
+
 	del_timer_sync(&ar_pci->ps_timer);
 
 	spin_lock_irqsave(&ar_pci->ps_lock, flags);
@@ -2397,6 +2446,15 @@ static int ath10k_pci_hif_resume(struct ath10k *ar)
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	struct pci_dev *pdev = ar_pci->pdev;
 	u32 val;
+	int ret = 0;
+
+	if (ar_pci->pci_ps == 0) {
+		ret = ath10k_pci_force_wake(ar);
+		if (ret) {
+			ath10k_err(ar, "failed to wake up target: %d\n", ret);
+			return ret;
+		}
+	}
 
 	/* Suspend/Resume resets the PCI configuration space, so we have to
 	 * re-disable the RETRY_TIMEOUT register (0x41) to keep PCI Tx retries
@@ -2407,7 +2465,7 @@ static int ath10k_pci_hif_resume(struct ath10k *ar)
 	if ((val & 0x0000ff00) != 0)
 		pci_write_config_dword(pdev, 0x40, val & 0xffff00ff);
 
-	return 0;
+	return ret;
 }
 #endif
 
@@ -2501,6 +2559,16 @@ static irqreturn_t ath10k_pci_interrupt_handler(int irq, void *arg)
 {
 	struct ath10k *ar = arg;
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
+	int ret;
+
+	if (ar_pci->pci_ps == 0) {
+		ret = ath10k_pci_force_wake(ar);
+		if (ret) {
+			ath10k_warn(ar, "failed to wake device up on irq: \
+					%d\n", ret);
+			return IRQ_NONE;
+		}
+	}
 
 	if (ar_pci->num_msi_intrs == 0) {
 		if (!ath10k_pci_irq_pending(ar))
@@ -2908,17 +2976,21 @@ static int ath10k_pci_probe(struct pci_dev *pdev,
 	struct ath10k_pci *ar_pci;
 	enum ath10k_hw_rev hw_rev;
 	u32 chip_id;
+	bool pci_ps;
 
 	switch (pci_dev->device) {
 	case QCA988X_2_0_DEVICE_ID:
 		hw_rev = ATH10K_HW_QCA988X;
+		pci_ps = false;
 		break;
 	case QCA6164_2_1_DEVICE_ID:
 	case QCA6174_2_1_DEVICE_ID:
 		hw_rev = ATH10K_HW_QCA6174;
+		pci_ps = true;
 		break;
 	case QCA99X0_2_0_DEVICE_ID:
 		hw_rev = ATH10K_HW_QCA99X0;
+		pci_ps = false;
 		break;
 	default:
 		WARN_ON(1);
@@ -2939,6 +3011,7 @@ static int ath10k_pci_probe(struct pci_dev *pdev,
 	ar_pci->dev = &pdev->dev;
 	ar_pci->ar = ar;
 	ar->dev_id = pci_dev->device;
+	ar_pci->pci_ps = pci_ps;
 
 	if (pdev->subsystem_vendor || pdev->subsystem_device)
 		scnprintf(ar->spec_board_id, sizeof(ar->spec_board_id),
@@ -2970,6 +3043,14 @@ static int ath10k_pci_probe(struct pci_dev *pdev,
 	ath10k_pci_ce_deinit(ar);
 	ath10k_pci_irq_disable(ar);
 
+	if (ar_pci->pci_ps == 0) {
+		ret = ath10k_pci_force_wake(ar);
+		if (ret) {
+			ath10k_warn(ar, "failed to wake up device : %d\n", ret);
+			goto err_free_pipes;
+		}
+	}
+
 	ret = ath10k_pci_init_irq(ar);
 	if (ret) {
 		ath10k_err(ar, "failed to init irqs: %d\n", ret);
diff --git a/drivers/net/wireless/ath/ath10k/pci.h b/drivers/net/wireless/ath/ath10k/pci.h
index 8d364fb..faba10d 100644
--- a/drivers/net/wireless/ath/ath10k/pci.h
+++ b/drivers/net/wireless/ath/ath10k/pci.h
@@ -221,6 +221,12 @@ struct ath10k_pci {
 	 * powersave register state changes.
 	 */
 	bool ps_awake;
+
+	/* pci power save, disable for QCA988X and QCA99X0.
+	 * Writing 'false' to this variable avoids frequent locking
+	 * on MMIO read/write.
+	 */
+	bool pci_ps;
 };
 
 static inline struct ath10k_pci *ath10k_pci_priv(struct ath10k *ar)
-- 
1.9.1