wifi: rtw89: pci: validate RX tag for RXQ and RPQ

PCI RX ring is a kind of read/write index ring, and DMA and ring index are
asynchronous, so suddenly driver gets newer index ahead before DMA. To
resolve this rare situation, we use a RX tag as helpers to make sure DMA
is done.

The RX tag is a 13-bit value, and range is from 1 ~ 0x1FFF, but 0 isn't
used so should be skipped.

Only enable this validation to coming WiFi 7 chips, because existing
chips use different design and don't really meet this situation.

Add missed rx_ring_eq_is_full for 8851BE by the way.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20240121071826.10159-4-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/pci.c

@@ -155,8 +155,8 @@ static void rtw89_pci_sync_skb_for_device(struct rtw89_dev *rtwdev,
 				   DMA_FROM_DEVICE);
 }
 
-static int rtw89_pci_rxbd_info_update(struct rtw89_dev *rtwdev,
-				      struct sk_buff *skb)
+static void rtw89_pci_rxbd_info_update(struct rtw89_dev *rtwdev,
+				       struct sk_buff *skb)
 {
 	struct rtw89_pci_rxbd_info *rxbd_info;
 	struct rtw89_pci_rx_info *rx_info = RTW89_PCI_RX_SKB_CB(skb);
@@ -166,10 +166,58 @@ static int rtw89_pci_rxbd_info_update(struct rtw89_dev *rtwdev,
 	rx_info->ls = le32_get_bits(rxbd_info->dword, RTW89_PCI_RXBD_LS);
 	rx_info->len = le32_get_bits(rxbd_info->dword, RTW89_PCI_RXBD_WRITE_SIZE);
 	rx_info->tag = le32_get_bits(rxbd_info->dword, RTW89_PCI_RXBD_TAG);
+}
+
+static int rtw89_pci_validate_rx_tag(struct rtw89_dev *rtwdev,
+				     struct rtw89_pci_rx_ring *rx_ring,
+				     struct sk_buff *skb)
+{
+	struct rtw89_pci_rx_info *rx_info = RTW89_PCI_RX_SKB_CB(skb);
+	const struct rtw89_pci_info *info = rtwdev->pci_info;
+	u32 target_rx_tag;
+
+	if (!info->check_rx_tag)
+		return 0;
+
+	/* valid range is 1 ~ 0x1FFF */
+	if (rx_ring->target_rx_tag == 0)
+		target_rx_tag = 1;
+	else
+		target_rx_tag = rx_ring->target_rx_tag;
+
+	if (rx_info->tag != target_rx_tag) {
+		rtw89_debug(rtwdev, RTW89_DBG_UNEXP, "mismatch RX tag 0x%x 0x%x\n",
+			    rx_info->tag, target_rx_tag);
+		return -EAGAIN;
+	}
 
 	return 0;
 }
 
+static
+int rtw89_pci_sync_skb_for_device_and_validate_rx_info(struct rtw89_dev *rtwdev,
+						       struct rtw89_pci_rx_ring *rx_ring,
+						       struct sk_buff *skb)
+{
+	struct rtw89_pci_rx_info *rx_info = RTW89_PCI_RX_SKB_CB(skb);
+	int rx_tag_retry = 100;
+	int ret;
+
+	do {
+		rtw89_pci_sync_skb_for_cpu(rtwdev, skb);
+		rtw89_pci_rxbd_info_update(rtwdev, skb);
+
+		ret = rtw89_pci_validate_rx_tag(rtwdev, rx_ring, skb);
+		if (ret != -EAGAIN)
+			break;
+	} while (rx_tag_retry--);
+
+	/* update target rx_tag for next RX */
+	rx_ring->target_rx_tag = rx_info->tag + 1;
+
+	return ret;
+}
+
 static void rtw89_pci_ctrl_txdma_ch_pcie(struct rtw89_dev *rtwdev, bool enable)
 {
 	const struct rtw89_pci_info *info = rtwdev->pci_info;
@@ -259,9 +307,8 @@ static u32 rtw89_pci_rxbd_deliver_skbs(struct rtw89_dev *rtwdev,
 
 	skb_idx = rtw89_pci_get_rx_skb_idx(rtwdev, bd_ring);
 	skb = rx_ring->buf[skb_idx];
-	rtw89_pci_sync_skb_for_cpu(rtwdev, skb);
 
-	ret = rtw89_pci_rxbd_info_update(rtwdev, skb);
+	ret = rtw89_pci_sync_skb_for_device_and_validate_rx_info(rtwdev, rx_ring, skb);
 	if (ret) {
 		rtw89_err(rtwdev, "failed to update %d RXBD info: %d\n",
 			  bd_ring->wp, ret);
@@ -549,9 +596,8 @@ static u32 rtw89_pci_release_tx_skbs(struct rtw89_dev *rtwdev,
 
 	skb_idx = rtw89_pci_get_rx_skb_idx(rtwdev, bd_ring);
 	skb = rx_ring->buf[skb_idx];
-	rtw89_pci_sync_skb_for_cpu(rtwdev, skb);
 
-	ret = rtw89_pci_rxbd_info_update(rtwdev, skb);
+	ret = rtw89_pci_sync_skb_for_device_and_validate_rx_info(rtwdev, rx_ring, skb);
 	if (ret) {
 		rtw89_err(rtwdev, "failed to update %d RXBD info: %d\n",
 			  bd_ring->wp, ret);
@@ -1550,6 +1596,7 @@ static void rtw89_pci_reset_trx_rings(struct rtw89_dev *rtwdev)
 		bd_ring->rp = 0;
 		rx_ring->diliver_skb = NULL;
 		rx_ring->diliver_desc.ready = false;
+		rx_ring->target_rx_tag = 0;
 
 		rtw89_write16(rtwdev, addr_num, bd_ring->len);
 		rtw89_write32(rtwdev, addr_desa_l, bd_ring->dma);
@@ -3213,6 +3260,7 @@ static int rtw89_pci_alloc_rx_ring(struct rtw89_dev *rtwdev,
 	rx_ring->buf_sz = buf_sz;
 	rx_ring->diliver_skb = NULL;
 	rx_ring->diliver_desc.ready = false;
+	rx_ring->target_rx_tag = 0;
 
 	for (i = 0; i < len; i++) {
 		skb = dev_alloc_skb(buf_sz);

drivers/net/wireless/realtek/rtw89/pci.h

@@ -1235,6 +1235,7 @@ struct rtw89_pci_info {
 	enum mac_ax_pcie_func_ctrl io_rcy_en;
 	enum mac_ax_io_rcy_tmr io_rcy_tmr;
 	bool rx_ring_eq_is_full;
+	bool check_rx_tag;
 
 	u32 init_cfg_reg;
 	u32 txhci_en_bit;
@@ -1277,7 +1278,7 @@ struct rtw89_pci_tx_data {
 
 struct rtw89_pci_rx_info {
 	dma_addr_t dma;
-	u32 fs:1, ls:1, tag:11, len:14;
+	u32 fs:1, ls:1, tag:13, len:14;
 };
 
 #define RTW89_PCI_TXBD_OPTION_LS	BIT(14)
@@ -1406,6 +1407,7 @@ struct rtw89_pci_rx_ring {
 	u32 buf_sz;
 	struct sk_buff *diliver_skb;
 	struct rtw89_rx_desc_info diliver_desc;
+	u32 target_rx_tag:13;
 };
 
 struct rtw89_pci_isrs {

drivers/net/wireless/realtek/rtw89/rtw8851be.c

@@ -25,6 +25,8 @@ static const struct rtw89_pci_info rtw8851b_pci_info = {
 	.autok_en		= MAC_AX_PCIE_DISABLE,
 	.io_rcy_en		= MAC_AX_PCIE_DISABLE,
 	.io_rcy_tmr		= MAC_AX_IO_RCY_ANA_TMR_6MS,
+	.rx_ring_eq_is_full	= false,
+	.check_rx_tag		= false,
 
 	.init_cfg_reg		= R_AX_PCIE_INIT_CFG1,
 	.txhci_en_bit		= B_AX_TXHCI_EN,

drivers/net/wireless/realtek/rtw89/rtw8852ae.c

@@ -26,6 +26,7 @@ static const struct rtw89_pci_info rtw8852a_pci_info = {
 	.io_rcy_en		= MAC_AX_PCIE_DISABLE,
 	.io_rcy_tmr		= MAC_AX_IO_RCY_ANA_TMR_6MS,
 	.rx_ring_eq_is_full	= false,
+	.check_rx_tag		= false,
 
 	.init_cfg_reg		= R_AX_PCIE_INIT_CFG1,
 	.txhci_en_bit		= B_AX_TXHCI_EN,

drivers/net/wireless/realtek/rtw89/rtw8852be.c

@@ -26,6 +26,7 @@ static const struct rtw89_pci_info rtw8852b_pci_info = {
 	.io_rcy_en		= MAC_AX_PCIE_DISABLE,
 	.io_rcy_tmr		= MAC_AX_IO_RCY_ANA_TMR_6MS,
 	.rx_ring_eq_is_full	= false,
+	.check_rx_tag		= false,
 
 	.init_cfg_reg		= R_AX_PCIE_INIT_CFG1,
 	.txhci_en_bit		= B_AX_TXHCI_EN,

drivers/net/wireless/realtek/rtw89/rtw8852ce.c

@@ -35,6 +35,7 @@ static const struct rtw89_pci_info rtw8852c_pci_info = {
 	.io_rcy_en		= MAC_AX_PCIE_ENABLE,
 	.io_rcy_tmr		= MAC_AX_IO_RCY_ANA_TMR_6MS,
 	.rx_ring_eq_is_full	= false,
+	.check_rx_tag		= false,
 
 	.init_cfg_reg		= R_AX_HAXI_INIT_CFG1,
 	.txhci_en_bit		= B_AX_TXHCI_EN_V1,

drivers/net/wireless/realtek/rtw89/rtw8922ae.c

@@ -26,6 +26,7 @@ static const struct rtw89_pci_info rtw8922a_pci_info = {
 	.io_rcy_en		= MAC_AX_PCIE_ENABLE,
 	.io_rcy_tmr		= MAC_AX_IO_RCY_ANA_TMR_DEF,
 	.rx_ring_eq_is_full	= true,
+	.check_rx_tag		= true,
 
 	.init_cfg_reg		= R_BE_HAXI_INIT_CFG1,
 	.txhci_en_bit		= B_BE_TXDMA_EN,