ath10k: allow setting coverage class

Unfortunately ath10k does not generally allow modifying the coverage class
with the stock firmware and Qualcomm has so far refused to implement this
feature so that it can be properly supported in ath10k. If we however know
the registers that need to be modified for proper operation with a higher
coverage class, then we can do these modifications from the driver.

This is a hack and might cause subtle problems but as it's not enabled by
default (only when user space changes the coverage class explicitly) it should
not cause new problems for existing setups. But still this should be considered
as an experimental feature and used with caution.

This patch implements the support for first generation cards (QCA9880, QCA9887
and so on) which are based on a core that is similar to ath9k. The registers
are modified in place and need to be re-written every time the firmware sets
them. To achieve this the register status is verified after certain WMI events
from the firmware.

The coverage class may not be modified temporarily right after the card
re-initializes the registers. This is for example the case during scanning.

Thanks to Sebastian Gottschall <s.gottschall@dd-wrt.com> for initially
working on a userspace support for this. This patch wouldn't have been
possible without this documentation.

Signed-off-by: Benjamin Berg <benjamin@sipsolutions.net>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fit.fraunhofer.de>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

1 files changed, 142 insertions, 0 deletions

diff --git a/drivers/net/wireless/ath/ath10k/hw.c b/drivers/net/wireless/ath/ath10k/hw.c
index 675e75d66db2..33fb26833cd0 100644
--- a/drivers/net/wireless/ath/ath10k/hw.c
+++ b/drivers/net/wireless/ath/ath10k/hw.c
@@ -17,11 +17,14 @@
 #include <linux/types.h>
 #include "core.h"
 #include "hw.h"
+#include "hif.h"
+#include "wmi-ops.h"
 
 const struct ath10k_hw_regs qca988x_regs = {
 	.rtc_soc_base_address		= 0x00004000,
 	.rtc_wmac_base_address		= 0x00005000,
 	.soc_core_base_address		= 0x00009000,
+	.wlan_mac_base_address		= 0x00020000,
 	.ce_wrapper_base_address	= 0x00057000,
 	.ce0_base_address		= 0x00057400,
 	.ce1_base_address		= 0x00057800,
@@ -48,6 +51,7 @@ const struct ath10k_hw_regs qca6174_regs = {
 	.rtc_soc_base_address			= 0x00000800,
 	.rtc_wmac_base_address			= 0x00001000,
 	.soc_core_base_address			= 0x0003a000,
+	.wlan_mac_base_address			= 0x00020000,
 	.ce_wrapper_base_address		= 0x00034000,
 	.ce0_base_address			= 0x00034400,
 	.ce1_base_address			= 0x00034800,
@@ -74,6 +78,7 @@ const struct ath10k_hw_regs qca99x0_regs = {
 	.rtc_soc_base_address			= 0x00080000,
 	.rtc_wmac_base_address			= 0x00000000,
 	.soc_core_base_address			= 0x00082000,
+	.wlan_mac_base_address			= 0x00030000,
 	.ce_wrapper_base_address		= 0x0004d000,
 	.ce0_base_address			= 0x0004a000,
 	.ce1_base_address			= 0x0004a400,
@@ -109,6 +114,7 @@ const struct ath10k_hw_regs qca99x0_regs = {
 const struct ath10k_hw_regs qca4019_regs = {
 	.rtc_soc_base_address                   = 0x00080000,
 	.soc_core_base_address                  = 0x00082000,
+	.wlan_mac_base_address                  = 0x00030000,
 	.ce_wrapper_base_address                = 0x0004d000,
 	.ce0_base_address                       = 0x0004a000,
 	.ce1_base_address                       = 0x0004a400,
@@ -220,7 +226,143 @@ void ath10k_hw_fill_survey_time(struct ath10k *ar, struct survey_info *survey,
 	survey->time_busy = CCNT_TO_MSEC(ar, rcc);
 }
 
+/* The firmware does not support setting the coverage class. Instead this
+ * function monitors and modifies the corresponding MAC registers.
+ */
+static void ath10k_hw_qca988x_set_coverage_class(struct ath10k *ar,
+						 s16 value)
+{
+	u32 slottime_reg;
+	u32 slottime;
+	u32 timeout_reg;
+	u32 ack_timeout;
+	u32 cts_timeout;
+	u32 phyclk_reg;
+	u32 phyclk;
+	u64 fw_dbglog_mask;
+	u32 fw_dbglog_level;
+
+	mutex_lock(&ar->conf_mutex);
+
+	/* Only modify registers if the core is started. */
+	if ((ar->state != ATH10K_STATE_ON) &&
+	    (ar->state != ATH10K_STATE_RESTARTED))
+		goto unlock;
+
+	/* Retrieve the current values of the two registers that need to be
+	 * adjusted.
+	 */
+	slottime_reg = ath10k_hif_read32(ar, WLAN_MAC_BASE_ADDRESS +
+					     WAVE1_PCU_GBL_IFS_SLOT);
+	timeout_reg = ath10k_hif_read32(ar, WLAN_MAC_BASE_ADDRESS +
+					    WAVE1_PCU_ACK_CTS_TIMEOUT);
+	phyclk_reg = ath10k_hif_read32(ar, WLAN_MAC_BASE_ADDRESS +
+					   WAVE1_PHYCLK);
+	phyclk = MS(phyclk_reg, WAVE1_PHYCLK_USEC) + 1;
+
+	if (value < 0)
+		value = ar->fw_coverage.coverage_class;
+
+	/* Break out if the coverage class and registers have the expected
+	 * value.
+	 */
+	if (value == ar->fw_coverage.coverage_class &&
+	    slottime_reg == ar->fw_coverage.reg_slottime_conf &&
+	    timeout_reg == ar->fw_coverage.reg_ack_cts_timeout_conf &&
+	    phyclk_reg == ar->fw_coverage.reg_phyclk)
+		goto unlock;
+
+	/* Store new initial register values from the firmware. */
+	if (slottime_reg != ar->fw_coverage.reg_slottime_conf)
+		ar->fw_coverage.reg_slottime_orig = slottime_reg;
+	if (timeout_reg != ar->fw_coverage.reg_ack_cts_timeout_conf)
+		ar->fw_coverage.reg_ack_cts_timeout_orig = timeout_reg;
+	ar->fw_coverage.reg_phyclk = phyclk_reg;
+
+	/* Calculat new value based on the (original) firmware calculation. */
+	slottime_reg = ar->fw_coverage.reg_slottime_orig;
+	timeout_reg = ar->fw_coverage.reg_ack_cts_timeout_orig;
+
+	/* Do some sanity checks on the slottime register. */
+	if (slottime_reg % phyclk) {
+		ath10k_warn(ar,
+			    "failed to set coverage class: expected integer microsecond value in register\n");
+
+		goto store_regs;
+	}
+
+	slottime = MS(slottime_reg, WAVE1_PCU_GBL_IFS_SLOT);
+	slottime = slottime / phyclk;
+	if (slottime != 9 && slottime != 20) {
+		ath10k_warn(ar,
+			    "failed to set coverage class: expected slot time of 9 or 20us in HW register. It is %uus.\n",
+			    slottime);
+
+		goto store_regs;
+	}
+
+	/* Recalculate the register values by adding the additional propagation
+	 * delay (3us per coverage class).
+	 */
+
+	slottime = MS(slottime_reg, WAVE1_PCU_GBL_IFS_SLOT);
+	slottime += value * 3 * phyclk;
+	slottime = min_t(u32, slottime, WAVE1_PCU_GBL_IFS_SLOT_MAX);
+	slottime = SM(slottime, WAVE1_PCU_GBL_IFS_SLOT);
+	slottime_reg = (slottime_reg & ~WAVE1_PCU_GBL_IFS_SLOT_MASK) | slottime;
+
+	/* Update ack timeout (lower halfword). */
+	ack_timeout = MS(timeout_reg, WAVE1_PCU_ACK_CTS_TIMEOUT_ACK);
+	ack_timeout += 3 * value * phyclk;
+	ack_timeout = min_t(u32, ack_timeout, WAVE1_PCU_ACK_CTS_TIMEOUT_MAX);
+	ack_timeout = SM(ack_timeout, WAVE1_PCU_ACK_CTS_TIMEOUT_ACK);
+
+	/* Update cts timeout (upper halfword). */
+	cts_timeout = MS(timeout_reg, WAVE1_PCU_ACK_CTS_TIMEOUT_CTS);
+	cts_timeout += 3 * value * phyclk;
+	cts_timeout = min_t(u32, cts_timeout, WAVE1_PCU_ACK_CTS_TIMEOUT_MAX);
+	cts_timeout = SM(cts_timeout, WAVE1_PCU_ACK_CTS_TIMEOUT_CTS);
+
+	timeout_reg = ack_timeout | cts_timeout;
+
+	ath10k_hif_write32(ar,
+			   WLAN_MAC_BASE_ADDRESS + WAVE1_PCU_GBL_IFS_SLOT,
+			   slottime_reg);
+	ath10k_hif_write32(ar,
+			   WLAN_MAC_BASE_ADDRESS + WAVE1_PCU_ACK_CTS_TIMEOUT,
+			   timeout_reg);
+
+	/* Ensure we have a debug level of WARN set for the case that the
+	 * coverage class is larger than 0. This is important as we need to
+	 * set the registers again if the firmware does an internal reset and
+	 * this way we will be notified of the event.
+	 */
+	fw_dbglog_mask = ath10k_debug_get_fw_dbglog_mask(ar);
+	fw_dbglog_level = ath10k_debug_get_fw_dbglog_level(ar);
+
+	if (value > 0) {
+		if (fw_dbglog_level > ATH10K_DBGLOG_LEVEL_WARN)
+			fw_dbglog_level = ATH10K_DBGLOG_LEVEL_WARN;
+		fw_dbglog_mask = ~0;
+	}
+
+	ath10k_wmi_dbglog_cfg(ar, fw_dbglog_mask, fw_dbglog_level);
+
+store_regs:
+	/* After an error we will not retry setting the coverage class. */
+	spin_lock_bh(&ar->data_lock);
+	ar->fw_coverage.coverage_class = value;
+	spin_unlock_bh(&ar->data_lock);
+
+	ar->fw_coverage.reg_slottime_conf = slottime_reg;
+	ar->fw_coverage.reg_ack_cts_timeout_conf = timeout_reg;
+
+unlock:
+	mutex_unlock(&ar->conf_mutex);
+}
+
 const struct ath10k_hw_ops qca988x_ops = {
+	.set_coverage_class = ath10k_hw_qca988x_set_coverage_class,
 };
 
 static int ath10k_qca99x0_rx_desc_get_l3_pad_bytes(struct htt_rx_desc *rxd)