wil6210: prevent deep sleep of 60G device in critical paths

In idle times 60G device can enter deep sleep and turn off
its XTAL clock.
Host access triggers the device power-up flow which will hold
the AHB during XTAL stabilization until device switches from
slow-clock to XTAL clock.
This behavior can stall the PCIe bus for some arbitrary period
of time.
In order to prevent this stall, host can vote for High Latency
Access Policy (HALP) before reading from PCIe bus.
This vote will wakeup the device from deep sleep and prevent
deep sleep until unvote is done.

Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

1 files changed, 72 insertions, 3 deletions

diff --git a/drivers/net/wireless/ath/wil6210/main.c b/drivers/net/wireless/ath/wil6210/main.c
index 261bdabccc83..f7ed65144742 100644
--- a/drivers/net/wireless/ath/wil6210/main.c
+++ b/drivers/net/wireless/ath/wil6210/main.c
@@ -23,6 +23,8 @@
 #include "wmi.h"
 #include "boot_loader.h"
 
+#define WAIT_FOR_HALP_VOTE_MS 100
+
 bool debug_fw; /* = false; */
 module_param(debug_fw, bool, S_IRUGO);
 MODULE_PARM_DESC(debug_fw, " do not perform card reset. For FW debug");
@@ -132,6 +134,14 @@ void wil_memcpy_fromio_32(void *dst, const volatile void __iomem *src,
 		*d++ = __raw_readl(s++);
 }
 
+void wil_memcpy_fromio_halp_vote(struct wil6210_priv *wil, void *dst,
+				 const volatile void __iomem *src, size_t count)
+{
+	wil_halp_vote(wil);
+	wil_memcpy_fromio_32(dst, src, count);
+	wil_halp_unvote(wil);
+}
+
 void wil_memcpy_toio_32(volatile void __iomem *dst, const void *src,
 			size_t count)
 {
@@ -142,6 +152,15 @@ void wil_memcpy_toio_32(volatile void __iomem *dst, const void *src,
 		__raw_writel(*s++, d++);
 }
 
+void wil_memcpy_toio_halp_vote(struct wil6210_priv *wil,
+			       volatile void __iomem *dst,
+			       const void *src, size_t count)
+{
+	wil_halp_vote(wil);
+	wil_memcpy_toio_32(dst, src, count);
+	wil_halp_unvote(wil);
+}
+
 static void wil_disconnect_cid(struct wil6210_priv *wil, int cid,
 			       u16 reason_code, bool from_event)
 __acquires(&sta->tid_rx_lock) __releases(&sta->tid_rx_lock)
@@ -474,9 +493,11 @@ int wil_priv_init(struct wil6210_priv *wil)
 	mutex_init(&wil->wmi_mutex);
 	mutex_init(&wil->probe_client_mutex);
 	mutex_init(&wil->p2p_wdev_mutex);
+	mutex_init(&wil->halp.lock);
 
 	init_completion(&wil->wmi_ready);
 	init_completion(&wil->wmi_call);
+	init_completion(&wil->halp.comp);
 
 	wil->bcast_vring = -1;
 	setup_timer(&wil->connect_timer, wil_connect_timer_fn, (ulong)wil);
@@ -572,11 +593,10 @@ static inline void wil_release_cpu(struct wil6210_priv *wil)
 static void wil_set_oob_mode(struct wil6210_priv *wil, bool enable)
 {
 	wil_info(wil, "%s: enable=%d\n", __func__, enable);
-	if (enable) {
+	if (enable)
 		wil_s(wil, RGF_USER_USAGE_6, BIT_USER_OOB_MODE);
-	} else {
+	else
 		wil_c(wil, RGF_USER_USAGE_6, BIT_USER_OOB_MODE);
-	}
 }
 
 static int wil_target_reset(struct wil6210_priv *wil)
@@ -888,6 +908,7 @@ int wil_reset(struct wil6210_priv *wil, bool load_fw)
 	wil->ap_isolate = 0;
 	reinit_completion(&wil->wmi_ready);
 	reinit_completion(&wil->wmi_call);
+	reinit_completion(&wil->halp.comp);
 
 	if (load_fw) {
 		wil_configure_interrupt_moderation(wil);
@@ -1078,3 +1099,51 @@ int wil_find_cid(struct wil6210_priv *wil, const u8 *mac)
 
 	return rc;
 }
+
+void wil_halp_vote(struct wil6210_priv *wil)
+{
+	unsigned long rc;
+	unsigned long to_jiffies = msecs_to_jiffies(WAIT_FOR_HALP_VOTE_MS);
+
+	mutex_lock(&wil->halp.lock);
+
+	wil_dbg_misc(wil, "%s: start, HALP ref_cnt (%d)\n", __func__,
+		     wil->halp.ref_cnt);
+
+	if (++wil->halp.ref_cnt == 1) {
+		wil6210_set_halp(wil);
+		rc = wait_for_completion_timeout(&wil->halp.comp, to_jiffies);
+		if (!rc)
+			wil_err(wil, "%s: HALP vote timed out\n", __func__);
+		else
+			wil_dbg_misc(wil,
+				     "%s: HALP vote completed after %d ms\n",
+				     __func__,
+				     jiffies_to_msecs(to_jiffies - rc));
+	}
+
+	wil_dbg_misc(wil, "%s: end, HALP ref_cnt (%d)\n", __func__,
+		     wil->halp.ref_cnt);
+
+	mutex_unlock(&wil->halp.lock);
+}
+
+void wil_halp_unvote(struct wil6210_priv *wil)
+{
+	WARN_ON(wil->halp.ref_cnt == 0);
+
+	mutex_lock(&wil->halp.lock);
+
+	wil_dbg_misc(wil, "%s: start, HALP ref_cnt (%d)\n", __func__,
+		     wil->halp.ref_cnt);
+
+	if (--wil->halp.ref_cnt == 0) {
+		wil6210_clear_halp(wil);
+		wil_dbg_misc(wil, "%s: HALP unvote\n", __func__);
+	}
+
+	wil_dbg_misc(wil, "%s: end, HALP ref_cnt (%d)\n", __func__,
+		     wil->halp.ref_cnt);
+
+	mutex_unlock(&wil->halp.lock);
+}