path: root/package/kernel/mac80211/patches/600-0003-rt2x00-rt2800-serialize-shared-memory-access.patch

From 250a1b520cd7fdc0df4fc3fedea9066913f49ecf Mon Sep 17 00:00:00 2001
From: Gabor Juhos <juhosg@openwrt.org>
Date: Sat, 17 Aug 2013 19:31:42 +0200
Subject: [PATCH] rt2x00: rt2800: serialize shared memory access

The shared memory of the rt2800 devices is accessible
through the register offset range between 0x4000 and
0x8000. The size of this range is 16KB only and on
devices which have more than 16KB of shared memory either
the low or the high part of the memory is accessible at a
time.

Serialize all accesses to the shared memory by a mutex,
in order to avoid concurrent use of that.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
---
Changes since v1: ---
---
 drivers/net/wireless/rt2x00/rt2800lib.c  |   55 +++++++++++++++++++++++++++++-
 drivers/net/wireless/rt2x00/rt2800lib.h  |   32 +++++++++++++++++
 drivers/net/wireless/rt2x00/rt2800mmio.c |   26 ++++++++++++++
 drivers/net/wireless/rt2x00/rt2800mmio.h |    4 +++
 drivers/net/wireless/rt2x00/rt2800pci.c  |   14 ++++++++
 drivers/net/wireless/rt2x00/rt2800soc.c  |    3 ++
 drivers/net/wireless/rt2x00/rt2800usb.c  |   31 +++++++++++++++++
 7 files changed, 164 insertions(+), 1 deletion(-)

--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -451,11 +451,13 @@ void rt2800_mcu_request(struct rt2x00_de
 		rt2x00_set_field32(&reg, H2M_MAILBOX_CSR_CMD_TOKEN, token);
 		rt2x00_set_field32(&reg, H2M_MAILBOX_CSR_ARG0, arg0);
 		rt2x00_set_field32(&reg, H2M_MAILBOX_CSR_ARG1, arg1);
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_write_lock(rt2x00dev, H2M_MAILBOX_CSR, reg);
 
 		reg = 0;
 		rt2x00_set_field32(&reg, HOST_CMD_CSR_HOST_COMMAND, command);
 		rt2800_register_write_lock(rt2x00dev, HOST_CMD_CSR, reg);
+		rt2800_shared_mem_unlock(rt2x00dev);
 	}
 
 	mutex_unlock(&rt2x00dev->csr_mutex);
@@ -674,7 +676,9 @@ int rt2800_load_firmware(struct rt2x00_d
 	 * Wait for device to stabilize.
 	 */
 	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_read(rt2x00dev, PBF_SYS_CTRL, &reg);
+		rt2800_shared_mem_unlock(rt2x00dev);
 		if (rt2x00_get_field32(reg, PBF_SYS_CTRL_READY))
 			break;
 		msleep(1);
@@ -694,10 +698,16 @@ int rt2800_load_firmware(struct rt2x00_d
 	/*
 	 * Initialize firmware.
 	 */
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
 	rt2800_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
+	rt2800_shared_mem_unlock(rt2x00dev);
+
 	if (rt2x00_is_usb(rt2x00dev)) {
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_write(rt2x00dev, H2M_INT_SRC, 0);
+		rt2800_shared_mem_unlock(rt2x00dev);
+
 		rt2800_mcu_request(rt2x00dev, MCU_BOOT_SIGNAL, 0, 0, 0);
 	}
 	msleep(1);
@@ -1035,8 +1045,10 @@ void rt2800_write_beacon(struct queue_en
 
 	beacon_base = rt2800_hw_beacon_base(rt2x00dev, entry->entry_idx);
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_multiwrite(rt2x00dev, beacon_base, entry->skb->data,
 				   entry->skb->len + padding_len);
+	rt2800_shared_mem_unlock(rt2x00dev);
 	__set_bit(ENTRY_BCN_ENABLED, &entry->flags);
 
 	/*
@@ -1066,6 +1078,8 @@ static inline void rt2800_clear_beacon_r
 
 	beacon_base = rt2800_hw_beacon_base(rt2x00dev, index);
 
+	rt2800_shared_mem_lock(rt2x00dev);
+
 	/*
 	 * For the Beacon base registers we only need to clear
 	 * the whole TXWI which (when set to 0) will invalidate
@@ -1073,6 +1087,8 @@ static inline void rt2800_clear_beacon_r
 	 */
 	for (i = 0; i < txwi_desc_size; i += sizeof(__le32))
 		rt2800_register_write(rt2x00dev, beacon_base + i, 0);
+
+	rt2800_shared_mem_unlock(rt2x00dev);
 }
 
 void rt2800_clear_beacon(struct queue_entry *entry)
@@ -1261,7 +1277,9 @@ static void rt2800_delete_wcid_attr(stru
 {
 	u32 offset;
 	offset = MAC_WCID_ATTR_ENTRY(wcid);
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_write(rt2x00dev, offset, 0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 }
 
 static void rt2800_config_wcid_attr_bssidx(struct rt2x00_dev *rt2x00dev,
@@ -1274,11 +1292,13 @@ static void rt2800_config_wcid_attr_bssi
 	 * The BSS Idx numbers is split in a main value of 3 bits,
 	 * and a extended field for adding one additional bit to the value.
 	 */
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_read(rt2x00dev, offset, &reg);
 	rt2x00_set_field32(&reg, MAC_WCID_ATTRIBUTE_BSS_IDX, (bssidx & 0x7));
 	rt2x00_set_field32(&reg, MAC_WCID_ATTRIBUTE_BSS_IDX_EXT,
 			   (bssidx & 0x8) >> 3);
 	rt2800_register_write(rt2x00dev, offset, reg);
+	rt2800_shared_mem_unlock(rt2x00dev);
 }
 
 static void rt2800_config_wcid_attr_cipher(struct rt2x00_dev *rt2x00dev,
@@ -1291,6 +1311,7 @@ static void rt2800_config_wcid_attr_ciph
 
 	offset = MAC_WCID_ATTR_ENTRY(key->hw_key_idx);
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	if (crypto->cmd == SET_KEY) {
 		rt2800_register_read(rt2x00dev, offset, &reg);
 		rt2x00_set_field32(&reg, MAC_WCID_ATTRIBUTE_KEYTAB,
@@ -1315,6 +1336,7 @@ static void rt2800_config_wcid_attr_ciph
 		rt2x00_set_field32(&reg, MAC_WCID_ATTRIBUTE_RX_WIUDF, 0);
 		rt2800_register_write(rt2x00dev, offset, reg);
 	}
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	offset = MAC_IVEIV_ENTRY(key->hw_key_idx);
 
@@ -1324,8 +1346,11 @@ static void rt2800_config_wcid_attr_ciph
 	    (crypto->cipher == CIPHER_AES))
 		iveiv_entry.iv[3] |= 0x20;
 	iveiv_entry.iv[3] |= key->keyidx << 6;
+
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_multiwrite(rt2x00dev, offset,
 				      &iveiv_entry, sizeof(iveiv_entry));
+	rt2800_shared_mem_unlock(rt2x00dev);
 }
 
 int rt2800_config_shared_key(struct rt2x00_dev *rt2x00dev,
@@ -1348,8 +1373,11 @@ int rt2800_config_shared_key(struct rt2x
 		       sizeof(key_entry.rx_mic));
 
 		offset = SHARED_KEY_ENTRY(key->hw_key_idx);
+
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_multiwrite(rt2x00dev, offset,
 					      &key_entry, sizeof(key_entry));
+		rt2800_shared_mem_unlock(rt2x00dev);
 	}
 
 	/*
@@ -1364,10 +1392,12 @@ int rt2800_config_shared_key(struct rt2x
 
 	offset = SHARED_KEY_MODE_ENTRY(key->hw_key_idx / 8);
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_read(rt2x00dev, offset, &reg);
 	rt2x00_set_field32(&reg, field,
 			   (crypto->cmd == SET_KEY) * crypto->cipher);
 	rt2800_register_write(rt2x00dev, offset, reg);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	/*
 	 * Update WCID information
@@ -1437,8 +1467,11 @@ int rt2800_config_pairwise_key(struct rt
 		       sizeof(key_entry.rx_mic));
 
 		offset = PAIRWISE_KEY_ENTRY(key->hw_key_idx);
+
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_multiwrite(rt2x00dev, offset,
 					      &key_entry, sizeof(key_entry));
+		rt2800_shared_mem_unlock(rt2x00dev);
 	}
 
 	/*
@@ -4908,14 +4941,19 @@ static int rt2800_init_registers(struct
 	/*
 	 * ASIC will keep garbage value after boot, clear encryption keys.
 	 */
+	rt2800_shared_mem_lock(rt2x00dev);
 	for (i = 0; i < 4; i++)
 		rt2800_register_write(rt2x00dev,
 					 SHARED_KEY_MODE_ENTRY(i), 0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	for (i = 0; i < 256; i++) {
 		rt2800_config_wcid(rt2x00dev, NULL, i);
 		rt2800_delete_wcid_attr(rt2x00dev, i);
+
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_write(rt2x00dev, MAC_IVEIV_ENTRY(i), 0);
+		rt2800_shared_mem_unlock(rt2x00dev);
 	}
 
 	/*
@@ -5041,8 +5079,10 @@ static int rt2800_wait_bbp_ready(struct
 	 * BBP was enabled after firmware was loaded,
 	 * but we need to reactivate it now.
 	 */
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
 	rt2800_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 	msleep(1);
 
 	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
@@ -6738,11 +6778,19 @@ int rt2800_enable_radio(struct rt2x00_de
 	/*
 	 * Send signal during boot time to initialize firmware.
 	 */
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
 	rt2800_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
-	if (rt2x00_is_usb(rt2x00dev))
+	rt2800_shared_mem_unlock(rt2x00dev);
+
+	if (rt2x00_is_usb(rt2x00dev)) {
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2800_register_write(rt2x00dev, H2M_INT_SRC, 0);
+		rt2800_shared_mem_unlock(rt2x00dev);
+	}
+
 	rt2800_mcu_request(rt2x00dev, MCU_BOOT_SIGNAL, 0, 0, 0);
+
 	msleep(1);
 
 	/*
@@ -7751,6 +7799,8 @@ int rt2800_probe_hw(struct rt2x00_dev *r
 	int retval;
 	u32 reg;
 
+	rt2800_shared_mem_init_lock(rt2x00dev);
+
 	retval = rt2800_probe_rt(rt2x00dev);
 	if (retval)
 		return retval;
@@ -7830,8 +7880,11 @@ void rt2800_get_tkip_seq(struct ieee8021
 	u32 offset;
 
 	offset = MAC_IVEIV_ENTRY(hw_key_idx);
+
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2800_register_multiread(rt2x00dev, offset,
 				      &iveiv_entry, sizeof(iveiv_entry));
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	memcpy(iv16, &iveiv_entry.iv[0], sizeof(*iv16));
 	memcpy(iv32, &iveiv_entry.iv[4], sizeof(*iv32));
--- a/drivers/net/wireless/rt2x00/rt2800lib.h
+++ b/drivers/net/wireless/rt2x00/rt2800lib.h
@@ -35,6 +35,11 @@ struct rt2800_drv_data {
 	unsigned int tbtt_tick;
 
 	unsigned long rt2800_flags;
+
+	union {
+		spinlock_t spin;
+		struct mutex mutex;
+	} shmem_lock;
 };
 
 struct rt2800_ops {
@@ -65,6 +70,10 @@ struct rt2800_ops {
 				  const u8 *data, const size_t len);
 	int (*drv_init_registers)(struct rt2x00_dev *rt2x00dev);
 	__le32 *(*drv_get_txwi)(struct queue_entry *entry);
+
+	void (*shmem_init_lock)(struct rt2x00_dev *rt2x00dev);
+	void (*shmem_lock)(struct rt2x00_dev *rt2x00dev);
+	void (*shmem_unlock)(struct rt2x00_dev *rt2x00dev);
 };
 
 static inline bool rt2800_has_high_shared_mem(struct rt2x00_dev *rt2x00dev)
@@ -74,6 +83,29 @@ static inline bool rt2800_has_high_share
 	return test_bit(RT2800_HAS_HIGH_SHARED_MEM, &drv_data->rt2800_flags);
 }
 
+static inline void rt2800_shared_mem_init_lock(struct rt2x00_dev *rt2x00dev)
+{
+	const struct rt2800_ops *rt2800ops = rt2x00dev->ops->drv;
+
+	rt2800ops->shmem_init_lock(rt2x00dev);
+}
+
+static inline void rt2800_shared_mem_lock(struct rt2x00_dev *rt2x00dev)
+{
+	const struct rt2800_ops *rt2800ops = rt2x00dev->ops->drv;
+
+	if (rt2800_has_high_shared_mem(rt2x00dev))
+		rt2800ops->shmem_lock(rt2x00dev);
+}
+
+static inline void rt2800_shared_mem_unlock(struct rt2x00_dev *rt2x00dev)
+{
+	const struct rt2800_ops *rt2800ops = rt2x00dev->ops->drv;
+
+	if (rt2800_has_high_shared_mem(rt2x00dev))
+		rt2800ops->shmem_unlock(rt2x00dev);
+}
+
 static inline void rt2800_register_read(struct rt2x00_dev *rt2x00dev,
 					const unsigned int offset,
 					u32 *value)
--- a/drivers/net/wireless/rt2x00/rt2800mmio.c
+++ b/drivers/net/wireless/rt2x00/rt2800mmio.c
@@ -820,8 +820,10 @@ int rt2800mmio_init_registers(struct rt2
 	rt2x00_set_field32(&reg, WPDMA_RST_IDX_DRX_IDX0, 1);
 	rt2x00mmio_register_write(rt2x00dev, WPDMA_RST_IDX, reg);
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00mmio_register_write(rt2x00dev, PBF_SYS_CTRL, 0x00000e1f);
 	rt2x00mmio_register_write(rt2x00dev, PBF_SYS_CTRL, 0x00000e00);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	if (rt2x00_is_pcie(rt2x00dev) &&
 	    (rt2x00_rt(rt2x00dev, RT3090) ||
@@ -865,6 +867,30 @@ int rt2800mmio_enable_radio(struct rt2x0
 }
 EXPORT_SYMBOL_GPL(rt2800mmio_enable_radio);
 
+void rt2800mmio_shmem_init_lock(struct rt2x00_dev *rt2x00dev)
+{
+	struct rt2800_drv_data *drv_data = rt2x00dev->drv_data;
+
+	spin_lock_init(&drv_data->shmem_lock.spin);
+}
+EXPORT_SYMBOL_GPL(rt2800mmio_shmem_init_lock);
+
+void rt2800mmio_shmem_lock(struct rt2x00_dev *rt2x00dev)
+{
+	struct rt2800_drv_data *drv_data = rt2x00dev->drv_data;
+
+	spin_lock_bh(&drv_data->shmem_lock.spin);
+}
+EXPORT_SYMBOL_GPL(rt2800mmio_shmem_lock);
+
+void rt2800mmio_shmem_unlock(struct rt2x00_dev *rt2x00dev)
+{
+	struct rt2800_drv_data *drv_data = rt2x00dev->drv_data;
+
+	spin_unlock_bh(&drv_data->shmem_lock.spin);
+}
+EXPORT_SYMBOL_GPL(rt2800mmio_shmem_unlock);
+
 MODULE_AUTHOR(DRV_PROJECT);
 MODULE_VERSION(DRV_VERSION);
 MODULE_DESCRIPTION("rt2800 MMIO library");
--- a/drivers/net/wireless/rt2x00/rt2800mmio.h
+++ b/drivers/net/wireless/rt2x00/rt2800mmio.h
@@ -160,4 +160,8 @@ int rt2800mmio_init_registers(struct rt2
 /* Device state switch handlers. */
 int rt2800mmio_enable_radio(struct rt2x00_dev *rt2x00dev);
 
+void rt2800mmio_shmem_init_lock(struct rt2x00_dev *rt2x00dev);
+void rt2800mmio_shmem_lock(struct rt2x00_dev *rt2x00dev);
+void rt2800mmio_shmem_unlock(struct rt2x00_dev *rt2x00dev);
+
 #endif /* RT2800MMIO_H */
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -69,7 +69,9 @@ static void rt2800pci_mcu_status(struct
 		return;
 
 	for (i = 0; i < 200; i++) {
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2x00mmio_register_read(rt2x00dev, H2M_MAILBOX_CID, &reg);
+		rt2800_shared_mem_unlock(rt2x00dev);
 
 		if ((rt2x00_get_field32(reg, H2M_MAILBOX_CID_CMD0) == token) ||
 		    (rt2x00_get_field32(reg, H2M_MAILBOX_CID_CMD1) == token) ||
@@ -83,8 +85,10 @@ static void rt2800pci_mcu_status(struct
 	if (i == 200)
 		rt2x00_err(rt2x00dev, "MCU request failed, no response from hardware\n");
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_STATUS, ~0);
 	rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_CID, ~0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 }
 
 static void rt2800pci_eepromregister_read(struct eeprom_93cx6 *eeprom)
@@ -184,6 +188,8 @@ static int rt2800pci_write_firmware(stru
 	 */
 	reg = 0;
 	rt2x00_set_field32(&reg, PBF_SYS_CTRL_HOST_RAM_WRITE, 1);
+
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00mmio_register_write(rt2x00dev, PBF_SYS_CTRL, reg);
 
 	/*
@@ -197,6 +203,7 @@ static int rt2800pci_write_firmware(stru
 
 	rt2x00mmio_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
 	rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	return 0;
 }
@@ -213,8 +220,10 @@ static int rt2800pci_enable_radio(struct
 		return retval;
 
 	/* After resume MCU_BOOT_SIGNAL will trash these. */
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_STATUS, ~0);
 	rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_CID, ~0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	rt2800_mcu_request(rt2x00dev, MCU_SLEEP, TOKEN_RADIO_OFF, 0xff, 0x02);
 	rt2800pci_mcu_status(rt2x00dev, TOKEN_RADIO_OFF);
@@ -233,10 +242,12 @@ static int rt2800pci_set_state(struct rt
 				   0, 0x02);
 		rt2800pci_mcu_status(rt2x00dev, TOKEN_WAKEUP);
 	} else if (state == STATE_SLEEP) {
+		rt2800_shared_mem_lock(rt2x00dev);
 		rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_STATUS,
 					  0xffffffff);
 		rt2x00mmio_register_write(rt2x00dev, H2M_MAILBOX_CID,
 					  0xffffffff);
+		rt2800_shared_mem_unlock(rt2x00dev);
 		rt2800_mcu_request(rt2x00dev, MCU_SLEEP, TOKEN_SLEEP,
 				   0xff, 0x01);
 	}
@@ -337,6 +348,9 @@ static const struct rt2800_ops rt2800pci
 	.drv_write_firmware	= rt2800pci_write_firmware,
 	.drv_init_registers	= rt2800mmio_init_registers,
 	.drv_get_txwi		= rt2800mmio_get_txwi,
+	.shmem_init_lock	= rt2800mmio_shmem_init_lock,
+	.shmem_lock		= rt2800mmio_shmem_lock,
+	.shmem_unlock		= rt2800mmio_shmem_unlock,
 };
 
 static const struct rt2x00lib_ops rt2800pci_rt2x00_ops = {
--- a/drivers/net/wireless/rt2x00/rt2800soc.c
+++ b/drivers/net/wireless/rt2x00/rt2800soc.c
@@ -176,6 +176,9 @@ static const struct rt2800_ops rt2800soc
 	.drv_write_firmware	= rt2800soc_write_firmware,
 	.drv_init_registers	= rt2800mmio_init_registers,
 	.drv_get_txwi		= rt2800mmio_get_txwi,
+	.shmem_init_lock	= rt2800mmio_shmem_init_lock,
+	.shmem_lock		= rt2800mmio_shmem_lock,
+	.shmem_unlock		= rt2800mmio_shmem_unlock,
 };
 
 static const struct rt2x00lib_ops rt2800soc_rt2x00_ops = {
--- a/drivers/net/wireless/rt2x00/rt2800usb.c
+++ b/drivers/net/wireless/rt2x00/rt2800usb.c
@@ -51,6 +51,27 @@ static bool rt2800usb_hwcrypt_disabled(s
 	return modparam_nohwcrypt;
 }
 
+static void rt2800usb_shmem_init_lock(struct rt2x00_dev *rt2x00dev)
+{
+	struct rt2800_drv_data *drv_data = rt2x00dev->drv_data;
+
+	mutex_init(&drv_data->shmem_lock.mutex);
+}
+
+static void rt2800usb_shmem_lock(struct rt2x00_dev *rt2x00dev)
+{
+	struct rt2800_drv_data *drv_data = rt2x00dev->drv_data;
+
+	mutex_lock(&drv_data->shmem_lock.mutex);
+}
+
+static void rt2800usb_shmem_unlock(struct rt2x00_dev *rt2x00dev)
+{
+	struct rt2800_drv_data *drv_data = rt2x00dev->drv_data;
+
+	mutex_unlock(&drv_data->shmem_lock.mutex);
+}
+
 /*
  * Queue handlers.
  */
@@ -294,8 +315,10 @@ static int rt2800usb_write_firmware(stru
 					      data + offset, length);
 	}
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00usb_register_write(rt2x00dev, H2M_MAILBOX_CID, ~0);
 	rt2x00usb_register_write(rt2x00dev, H2M_MAILBOX_STATUS, ~0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	/*
 	 * Send firmware request to device to load firmware,
@@ -310,7 +333,10 @@ static int rt2800usb_write_firmware(stru
 	}
 
 	msleep(10);
+
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00usb_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	return 0;
 }
@@ -328,8 +354,10 @@ static int rt2800usb_init_registers(stru
 	if (rt2800_wait_csr_ready(rt2x00dev))
 		return -EBUSY;
 
+	rt2800_shared_mem_lock(rt2x00dev);
 	rt2x00usb_register_read(rt2x00dev, PBF_SYS_CTRL, &reg);
 	rt2x00usb_register_write(rt2x00dev, PBF_SYS_CTRL, reg & ~0x00002000);
+	rt2800_shared_mem_unlock(rt2x00dev);
 
 	reg = 0;
 	rt2x00_set_field32(&reg, MAC_SYS_CTRL_RESET_CSR, 1);
@@ -859,6 +887,9 @@ static const struct rt2800_ops rt2800usb
 	.drv_write_firmware	= rt2800usb_write_firmware,
 	.drv_init_registers	= rt2800usb_init_registers,
 	.drv_get_txwi		= rt2800usb_get_txwi,
+	.shmem_init_lock	= rt2800usb_shmem_init_lock,
+	.shmem_lock		= rt2800usb_shmem_lock,
+	.shmem_unlock		= rt2800usb_shmem_unlock,
 };
 
 static const struct rt2x00lib_ops rt2800usb_rt2x00_ops = {