usb: mtu3: add memory barrier before set GPD's HWO

stable inclusion
from stable-v5.10.90
commit f10b01c48f856d5fc11fbef271e1bd9abcdf0f0d
bugzilla: 186168 https://gitee.com/openeuler/kernel/issues/I4SHY1

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f10b01c48f856d5fc11fbef271e1bd9abcdf0f0d

--------------------------------

commit a7aae769 upstream.

There is a seldom issue that the controller access invalid address
and trigger devapc or emimpu violation. That is due to memory access
is out of order and cause gpd data is not correct.
Add mb() to prohibit compiler or cpu from reordering to make sure GPD
is fully written before setting its HWO.

Fixes: 48e0d373 ("usb: mtu3: supports new QMU format")
Cc: stable@vger.kernel.org
Reported-by: NEddie Hung <eddie.hung@mediatek.com>
Signed-off-by: NChunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20211218095749.6250-2-chunfeng.yun@mediatek.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/usb/mtu3/mtu3_qmu.c

@@ -273,6 +273,8 @@ static int mtu3_prepare_tx_gpd(struct mtu3_ep *mep, struct mtu3_request *mreq)
 			gpd->dw3_info |= cpu_to_le32(GPD_EXT_FLAG_ZLP);
 	}
 
+	/* prevent reorder, make sure GPD's HWO is set last */
+	mb();
 	gpd->dw0_info |= cpu_to_le32(GPD_FLAGS_IOC | GPD_FLAGS_HWO);
 
 	mreq->gpd = gpd;
@@ -306,6 +308,8 @@ static int mtu3_prepare_rx_gpd(struct mtu3_ep *mep, struct mtu3_request *mreq)
 	gpd->next_gpd = cpu_to_le32(lower_32_bits(enq_dma));
 	ext_addr |= GPD_EXT_NGP(mtu, upper_32_bits(enq_dma));
 	gpd->dw3_info = cpu_to_le32(ext_addr);
+	/* prevent reorder, make sure GPD's HWO is set last */
+	mb();
 	gpd->dw0_info |= cpu_to_le32(GPD_FLAGS_IOC | GPD_FLAGS_HWO);
 
 	mreq->gpd = gpd;
@@ -445,7 +449,8 @@ static void qmu_tx_zlp_error_handler(struct mtu3 *mtu, u8 epnum)
 		return;
 	}
 	mtu3_setbits(mbase, MU3D_EP_TXCR0(mep->epnum), TX_TXPKTRDY);
-
+	/* prevent reorder, make sure GPD's HWO is set last */
+	mb();
 	/* by pass the current GDP */
 	gpd_current->dw0_info |= cpu_to_le32(GPD_FLAGS_BPS | GPD_FLAGS_HWO);