[PATCH AUTOSEL 5.9 07/39] iwlwifi: pcie: set LTR to avoid completion timeout

Sasha Levin
2020-12-03T13:30:21Z

From: Johannes Berg <johannes.berg@intel.com>

[ Upstream commit edb625208d84aef179e3f16590c1c582fc5fdae6 ]

On some platforms, the preset values aren't correct and then we may
get a completion timeout in the firmware. Change the LTR configuration
to avoid that. The firmware will do some more complex reinit of this
later, but for the boot process we use ~250usec.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20201107104557.d83d591c05ba.I42885c9fb500bc08b9a4c07c4ff3d436cc7a3c84@changeid
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/intel/iwlwifi/iwl-csr.h | 10 ++++++++++
.../intel/iwlwifi/pcie/ctxt-info-gen3.c | 20 +++++++++++++++++++
2 files changed, 30 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-csr.h b/drivers/net/wireless/intel/iwlwifi/iwl-csr.h
index cb9e8e189a1a4..1d48c7d7fffd4 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-csr.h
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-csr.h
@@ -147,6 +147,16 @@
#define CSR_MAC_SHADOW_REG_CTL2 (CSR_BASE + 0x0AC)
#define CSR_MAC_SHADOW_REG_CTL2_RX_WAKE 0xFFFF

+/* LTR control (since IWL_DEVICE_FAMILY_22000) */
+#define CSR_LTR_LONG_VAL_AD (CSR_BASE + 0x0D4)
+#define CSR_LTR_LONG_VAL_AD_NO_SNOOP_REQ 0x80000000
+#define CSR_LTR_LONG_VAL_AD_NO_SNOOP_SCALE 0x1c000000
+#define CSR_LTR_LONG_VAL_AD_NO_SNOOP_VAL 0x03ff0000
+#define CSR_LTR_LONG_VAL_AD_SNOOP_REQ 0x00008000
+#define CSR_LTR_LONG_VAL_AD_SNOOP_SCALE 0x00001c00
+#define CSR_LTR_LONG_VAL_AD_SNOOP_VAL 0x000003ff
+#define CSR_LTR_LONG_VAL_AD_SCALE_USEC 2
+
/* GIO Chicken Bits (PCI Express bus link power management) */
#define CSR_GIO_CHICKEN_BITS (CSR_BASE+0x100)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/ctxt-info-gen3.c b/drivers/net/wireless/intel/iwlwifi/pcie/ctxt-info-gen3.c
index 1ab1366004159..0fc2a6e49f9ee 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/ctxt-info-gen3.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/ctxt-info-gen3.c
@@ -252,6 +252,26 @@ int iwl_pcie_ctxt_info_gen3_init(struct iwl_trans *trans,

iwl_set_bit(trans, CSR_CTXT_INFO_BOOT_CTRL,
CSR_AUTO_FUNC_BOOT_ENA);
+
+ if (trans->trans_cfg->device_family == IWL_DEVICE_FAMILY_AX210) {
+ /*
+ * The firmware initializes this again later (to a smaller
+ * value), but for the boot process initialize the LTR to
+ * ~250 usec.
+ */
+ u32 val = CSR_LTR_LONG_VAL_AD_NO_SNOOP_REQ |
+ u32_encode_bits(CSR_LTR_LONG_VAL_AD_SCALE_USEC,
+ CSR_LTR_LONG_VAL_AD_NO_SNOOP_SCALE) |
+ u32_encode_bits(250,
+ CSR_LTR_LONG_VAL_AD_NO_SNOOP_VAL) |
+ CSR_LTR_LONG_VAL_AD_SNOOP_REQ |
+ u32_encode_bits(CSR_LTR_LONG_VAL_AD_SCALE_USEC,
+ CSR_LTR_LONG_VAL_AD_SNOOP_SCALE) |
+ u32_encode_bits(250, CSR_LTR_LONG_VAL_AD_SNOOP_VAL);
+
+ iwl_write32(trans, CSR_LTR_LONG_VAL_AD, val);
+ }
+
if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_AX210)
iwl_write_umac_prph(trans, UREG_CPU_INIT_RUN, 1);
else
--
2.27.0