iwlwifi: support firmware reset handshake

There are some races in the hardware that can possibly lead to
a bus lockup later during a restart when we manage to kill the
firmware at a bad time (while it's accessing the bus).

To work around this, add support for a new handshake between
firmware and driver to ensure that the firmware is in a well-
known state before we kill it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201209231352.7756fcc9865c.I13de65e0ffcb4186dd4c1a465f66df2e98c9a947@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/fw/file.h b/drivers/net/wireless/intel/iwlwifi/fw/file.h
index 4c3a1a1..597bc88 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/fw/file.h
+++ b/drivers/net/wireless/intel/iwlwifi/fw/file.h
@@ -359,6 +359,8 @@ typedef unsigned int __bitwise iwl_ucode_tlv_capa_t;
  *     initiator and responder
  * @IWL_UCODE_TLV_CAPA_MLME_OFFLOAD: supports MLME offload
  * @IWL_UCODE_TLV_CAPA_PROTECTED_TWT: Supports protection of TWT action frames
+ * @IWL_UCODE_TLV_CAPA_FW_RESET_HANDSHAKE: Supports the firmware handshake in
+ *     reset flow
  *
  * @NUM_IWL_UCODE_TLV_CAPA: number of bits used
  */
@@ -404,6 +406,7 @@ enum iwl_ucode_tlv_capa {
        IWL_UCODE_TLV_CAPA_TAS_CFG                      = (__force iwl_ucode_tlv_capa_t)53,
        IWL_UCODE_TLV_CAPA_SESSION_PROT_CMD             = (__force iwl_ucode_tlv_capa_t)54,
        IWL_UCODE_TLV_CAPA_PROTECTED_TWT                = (__force iwl_ucode_tlv_capa_t)56,
+       IWL_UCODE_TLV_CAPA_FW_RESET_HANDSHAKE           = (__force iwl_ucode_tlv_capa_t)57,
 
        /* set 2 */
        IWL_UCODE_TLV_CAPA_EXTENDED_DTS_MEASURE         = (__force iwl_ucode_tlv_capa_t)64,

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-csr.h b/drivers/net/wireless/intel/iwlwifi/iwl-csr.h
index 1ebb35f..fe0c03c 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/iwl-csr.h
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-csr.h
@@ -583,6 +583,7 @@ enum msix_hw_int_causes {
        MSIX_HW_INT_CAUSES_REG_ALIVE            = BIT(0),
        MSIX_HW_INT_CAUSES_REG_WAKEUP           = BIT(1),
        MSIX_HW_INT_CAUSES_REG_IML              = BIT(1),
+       MSIX_HW_INT_CAUSES_REG_RESET_DONE       = BIT(2),
        MSIX_HW_INT_CAUSES_REG_CT_KILL          = BIT(6),
        MSIX_HW_INT_CAUSES_REG_RF_KILL          = BIT(7),
        MSIX_HW_INT_CAUSES_REG_PERIODIC         = BIT(8),

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-prph.h b/drivers/net/wireless/intel/iwlwifi/iwl-prph.h
index 33753b8..0b03fde 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/iwl-prph.h
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-prph.h
@@ -55,6 +55,7 @@
 /* Device NMI register and value for 9000 family and above hw's */
 #define UREG_NIC_SET_NMI_DRIVER 0x00a05c10
 #define UREG_NIC_SET_NMI_DRIVER_NMI_FROM_DRIVER BIT(24)
+#define UREG_NIC_SET_NMI_DRIVER_RESET_HANDSHAKE (BIT(24) | BIT(25))
 
 /* Shared registers (0x0..0x3ff, via target indirect or periphery */
 #define SHR_BASE       0x00a10000
@@ -399,6 +400,7 @@ enum {
 
 #define UREG_DOORBELL_TO_ISR6          0xA05C04
 #define UREG_DOORBELL_TO_ISR6_NMI_BIT  BIT(0)
+#define UREG_DOORBELL_TO_ISR6_RESET_HANDSHAKE (BIT(0) | BIT(1))
 #define UREG_DOORBELL_TO_ISR6_SUSPEND  BIT(18)
 #define UREG_DOORBELL_TO_ISR6_RESUME   BIT(19)
 #define UREG_DOORBELL_TO_ISR6_PNVM     BIT(20)

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-trans.h b/drivers/net/wireless/intel/iwlwifi/iwl-trans.h
index 2c9dd3f..2d65bb8 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/iwl-trans.h
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-trans.h
@@ -380,6 +380,7 @@ struct iwl_hcmd_arr {
  * @command_groups_size: number of command groups, to avoid illegal access
  * @cb_data_offs: offset inside skb->cb to store transport data at, must have
  *     space for at least two pointers
+ * @fw_reset_handshake: firmware supports reset flow handshake
  */
 struct iwl_trans_config {
        struct iwl_op_mode *op_mode;
@@ -397,6 +398,7 @@ struct iwl_trans_config {
        int command_groups_size;
 
        u8 cb_data_offs;
+       bool fw_reset_handshake;
 };
 
 struct iwl_trans_dump_data {

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
index 4d7a3ff..fc5e66b 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/ops.c
@@ -728,6 +728,9 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
                 sizeof(mvm->hw->wiphy->fw_version),
                 "%s", fw->fw_version);
 
+       trans_cfg.fw_reset_handshake = fw_has_capa(&mvm->fw->ucode_capa,
+                                                  IWL_UCODE_TLV_CAPA_FW_RESET_HANDSHAKE);
+
        /* Configure transport layer */
        iwl_trans_configure(mvm->trans, &trans_cfg);
 

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
index 309dec9..a528d3d 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/internal.h
@@ -406,6 +406,10 @@ struct iwl_trans_pcie {
 
        void *base_rb_stts;
        dma_addr_t base_rb_stts_dma;
+
+       bool fw_reset_handshake;
+       bool fw_reset_done;
+       wait_queue_head_t fw_reset_waitq;
 };
 
 static inline struct iwl_trans_pcie *

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index e82356a..37bbd9a 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -2242,6 +2242,12 @@ irqreturn_t iwl_pcie_irq_msix_handler(int irq, void *dev_id)
                iwl_pcie_irq_handle_error(trans);
        }
 
+       if (inta_hw & MSIX_HW_INT_CAUSES_REG_RESET_DONE) {
+               IWL_DEBUG_ISR(trans, "Reset flow completed\n");
+               trans_pcie->fw_reset_done = true;
+               wake_up(&trans_pcie->fw_reset_waitq);
+       }
+
        iwl_pcie_clear_irq(trans, entry);
 
        lock_map_release(&trans->sync_cmd_lockdep_map);

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
index c25a2fb..c602b81 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans-gen2.c
@@ -88,6 +88,28 @@ static void iwl_pcie_gen2_apm_stop(struct iwl_trans *trans, bool op_mode_leave)
        iwl_clear_bit(trans, CSR_GP_CNTRL, CSR_GP_CNTRL_REG_FLAG_INIT_DONE);
 }
 
+static void iwl_trans_pcie_fw_reset_handshake(struct iwl_trans *trans)
+{
+       struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
+       int ret;
+
+       trans_pcie->fw_reset_done = false;
+
+       if (trans->trans_cfg->device_family < IWL_DEVICE_FAMILY_AX210)
+               iwl_write_umac_prph(trans, UREG_NIC_SET_NMI_DRIVER,
+                                   UREG_NIC_SET_NMI_DRIVER_RESET_HANDSHAKE);
+       else
+               iwl_write_umac_prph(trans, UREG_DOORBELL_TO_ISR6,
+                                   UREG_DOORBELL_TO_ISR6_RESET_HANDSHAKE);
+
+       /* wait 200ms */
+       ret = wait_event_timeout(trans_pcie->fw_reset_waitq,
+                                trans_pcie->fw_reset_done, HZ / 5);
+       if (!ret)
+               IWL_ERR(trans,
+                       "firmware didn't ACK the reset - continue anyway\n");
+}
+
 void _iwl_trans_pcie_gen2_stop_device(struct iwl_trans *trans)
 {
        struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
@@ -97,6 +119,10 @@ void _iwl_trans_pcie_gen2_stop_device(struct iwl_trans *trans)
        if (trans_pcie->is_down)
                return;
 
+       if (trans_pcie->fw_reset_handshake &&
+           trans->state >= IWL_TRANS_FW_STARTED)
+               iwl_trans_pcie_fw_reset_handshake(trans);
+
        trans_pcie->is_down = true;
 
        /* tell the device to stop sending interrupts */

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 2928634..285e0d5 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -1048,6 +1048,7 @@ static struct iwl_causes_list causes_list[] = {
        {MSIX_FH_INT_CAUSES_FH_ERR,             CSR_MSIX_FH_INT_MASK_AD, 0x5},
        {MSIX_HW_INT_CAUSES_REG_ALIVE,          CSR_MSIX_HW_INT_MASK_AD, 0x10},
        {MSIX_HW_INT_CAUSES_REG_WAKEUP,         CSR_MSIX_HW_INT_MASK_AD, 0x11},
+       {MSIX_HW_INT_CAUSES_REG_RESET_DONE,     CSR_MSIX_HW_INT_MASK_AD, 0x12},
        {MSIX_HW_INT_CAUSES_REG_CT_KILL,        CSR_MSIX_HW_INT_MASK_AD, 0x16},
        {MSIX_HW_INT_CAUSES_REG_RF_KILL,        CSR_MSIX_HW_INT_MASK_AD, 0x17},
        {MSIX_HW_INT_CAUSES_REG_PERIODIC,       CSR_MSIX_HW_INT_MASK_AD, 0x18},
@@ -1889,6 +1890,8 @@ static void iwl_trans_pcie_configure(struct iwl_trans *trans,
         */
        if (trans_pcie->napi_dev.reg_state != NETREG_DUMMY)
                init_dummy_netdev(&trans_pcie->napi_dev);
+
+       trans_pcie->fw_reset_handshake = trans_cfg->fw_reset_handshake;
 }
 
 void iwl_trans_pcie_free(struct iwl_trans *trans)
@@ -3403,6 +3406,7 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
        spin_lock_init(&trans_pcie->alloc_page_lock);
        mutex_init(&trans_pcie->mutex);
        init_waitqueue_head(&trans_pcie->ucode_write_waitq);
+       init_waitqueue_head(&trans_pcie->fw_reset_waitq);
 
        trans_pcie->rba.alloc_wq = alloc_workqueue("rb_allocator",
                                                   WQ_HIGHPRI | WQ_UNBOUND, 1);