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

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: 48e0d3735a ("usb: mtu3: supports new QMU format")
Cc: stable@vger.kernel.org
Reported-by: Eddie Hung <eddie.hung@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20211218095749.6250-2-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Chunfeng Yun 2021-12-18 17:57:47 +08:00 committed by Greg Kroah-Hartman
parent e3d4621c22
commit a7aae769ca
1 changed files with 6 additions and 1 deletions
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7
drivers/usb/mtu3/mtu3_qmu.c
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@ -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);