staging: r8188eu: add error handling of rtw_read8

_rtw_read8 function can fail in case of usb transfer failure. But
previous function prototype wasn't designed to return an error to
caller. It can cause a lot uninit value bugs all across the driver code,
since rtw_read8() returns local stack variable to caller.

Fix it by changing the prototype of this function. Now it returns an
int: 0 on success, negative error value on failure and callers should pass
the pointer to storage location for register value.

Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>

drivers/staging/r8188eu/core/rtw_debug.c

@@ -73,8 +73,8 @@ int proc_get_read_reg(char *page, char **start,
 {
 	struct net_device *dev = data;
 	struct adapter *padapter = (struct adapter *)rtw_netdev_priv(dev);
-
-	int len = 0;
+	u32 tmp;
+	int len = 0, error;
 
 	if (proc_get_read_addr == 0xeeeeeeee) {
 		*eof = 1;
@@ -83,7 +83,12 @@ int proc_get_read_reg(char *page, char **start,
 
 	switch (proc_get_read_len) {
 	case 1:
-		len += snprintf(page + len, count - len, "rtw_read8(0x%x)=0x%x\n", proc_get_read_addr, rtw_read8(padapter, proc_get_read_addr));
+		error = rtw_read8(padapter, proc_get_read_addr, (u8 *) &tmp);
+		if (error)
+			return len;
+
+		len += snprintf(page + len, count - len, "rtw_read8(0x%x)=0x%x\n",
+				proc_get_read_addr, (u8) tmp);
 		break;
 	case 2:
 		len += snprintf(page + len, count - len, "rtw_read16(0x%x)=0x%x\n", proc_get_read_addr, rtw_read16(padapter, proc_get_read_addr));

drivers/staging/r8188eu/core/rtw_efuse.c

@@ -159,6 +159,7 @@ ReadEFuseByte(
 	u32 value32;
 	u8 readbyte;
 	u16 retry;
+	int error;
 
 	if (pseudo) {
 		Efuse_Read1ByteFromFakeContent(Adapter, _offset, pbuf);
@@ -167,11 +168,17 @@ ReadEFuseByte(
 
 	/* Write Address */
 	rtw_write8(Adapter, EFUSE_CTRL + 1, (_offset & 0xff));
-	readbyte = rtw_read8(Adapter, EFUSE_CTRL + 2);
+	error = rtw_read8(Adapter, EFUSE_CTRL + 2, &readbyte);
+	if (error)
+		return;
+
 	rtw_write8(Adapter, EFUSE_CTRL + 2, ((_offset >> 8) & 0x03) | (readbyte & 0xfc));
 
 	/* Write bit 32 0 */
-	readbyte = rtw_read8(Adapter, EFUSE_CTRL + 3);
+	error = rtw_read8(Adapter, EFUSE_CTRL + 3, &readbyte);
+	if (error)
+		return;
+
 	rtw_write8(Adapter, EFUSE_CTRL + 3, (readbyte & 0x7f));
 
 	/* Check bit 32 read-ready */
@@ -244,34 +251,50 @@ u8 EFUSE_Read1Byte(struct adapter *Adapter, u16 Address)
 	u8 temp = {0x00};
 	u32 k = 0;
 	u16 contentLen = 0;
+	int error;
 
 	EFUSE_GetEfuseDefinition(Adapter, EFUSE_WIFI, TYPE_EFUSE_REAL_CONTENT_LEN, (void *)&contentLen, false);
 
 	if (Address < contentLen) {	/* E-fuse 512Byte */
 		/* Write E-fuse Register address bit0~7 */
 		temp = Address & 0xFF;
 		rtw_write8(Adapter, EFUSE_CTRL + 1, temp);
-		Bytetemp = rtw_read8(Adapter, EFUSE_CTRL + 2);
+		error = rtw_read8(Adapter, EFUSE_CTRL + 2, &Bytetemp);
+		if (error)
+			return 0xFF;
+
 		/* Write E-fuse Register address bit8~9 */
 		temp = ((Address >> 8) & 0x03) | (Bytetemp & 0xFC);
 		rtw_write8(Adapter, EFUSE_CTRL + 2, temp);
 
 		/* Write 0x30[31]= 0 */
-		Bytetemp = rtw_read8(Adapter, EFUSE_CTRL + 3);
+		error = rtw_read8(Adapter, EFUSE_CTRL + 3, &Bytetemp);
+		if (error)
+			return 0xFF;
+
 		temp = Bytetemp & 0x7F;
 		rtw_write8(Adapter, EFUSE_CTRL + 3, temp);
 
 		/* Wait Write-ready (0x30[31]= 1) */
-		Bytetemp = rtw_read8(Adapter, EFUSE_CTRL + 3);
+		error = rtw_read8(Adapter, EFUSE_CTRL + 3, &Bytetemp);
+		if (error)
+			return 0xFF;
+
 		while (!(Bytetemp & 0x80)) {
-			Bytetemp = rtw_read8(Adapter, EFUSE_CTRL + 3);
+			error = rtw_read8(Adapter, EFUSE_CTRL + 3, &Bytetemp);
+			if (error)
+				return 0xFF;
+
 			k++;
 			if (k == 1000) {
 				k = 0;
 				break;
 			}
 		}
-		data = rtw_read8(Adapter, EFUSE_CTRL);
+		error = rtw_read8(Adapter, EFUSE_CTRL, &data);
+		if (error)
+			return 0xFF;
+
 		return data;
 	} else {
 		return 0xFF;
@@ -284,6 +307,8 @@ u8 efuse_OneByteRead(struct adapter *pAdapter, u16 addr, u8 *data, bool pseudo)
 {
 	u8 tmpidx = 0;
 	u8 result;
+	u8 tmp;
+	int error;
 
 	if (pseudo) {
 		result = Efuse_Read1ByteFromFakeContent(pAdapter, addr, data);
@@ -292,16 +317,25 @@ u8 efuse_OneByteRead(struct adapter *pAdapter, u16 addr, u8 *data, bool pseudo)
 	/*  -----------------e-fuse reg ctrl --------------------------------- */
 	/* address */
 	rtw_write8(pAdapter, EFUSE_CTRL + 1, (u8)(addr & 0xff));
-	rtw_write8(pAdapter, EFUSE_CTRL + 2, ((u8)((addr >> 8) & 0x03)) |
-		   (rtw_read8(pAdapter, EFUSE_CTRL + 2) & 0xFC));
+	error = rtw_read8(pAdapter, EFUSE_CTRL + 2, &tmp);
+	if (error)
+		return false;
 
+	rtw_write8(pAdapter, EFUSE_CTRL + 2, ((u8)((addr >> 8) & 0x03)) | (tmp & 0xFC));
 	rtw_write8(pAdapter, EFUSE_CTRL + 3,  0x72);/* read cmd */
 
-	while (!(0x80 & rtw_read8(pAdapter, EFUSE_CTRL + 3)) && (tmpidx < 100))
-		tmpidx++;
+	do {
+		error = rtw_read8(pAdapter, EFUSE_CTRL + 3, &tmp);
+		if (error)
+			return false;
+	} while (!(0x80 & tmp) && (++tmpidx < 100));
+
 	if (tmpidx < 100) {
-		*data = rtw_read8(pAdapter, EFUSE_CTRL);
-		result = true;
+		error = rtw_read8(pAdapter, EFUSE_CTRL, data);
+		if (error)
+			result = false;
+		else
+			result = true;
 	} else {
 		*data = 0xff;
 		result = false;
@@ -314,6 +348,8 @@ u8 efuse_OneByteWrite(struct adapter *pAdapter, u16 addr, u8 data, bool pseudo)
 {
 	u8 tmpidx = 0;
 	u8 result;
+	u8 tmp;
+	int error;
 
 	if (pseudo) {
 		result = Efuse_Write1ByteToFakeContent(pAdapter, addr, data);
@@ -323,15 +359,23 @@ u8 efuse_OneByteWrite(struct adapter *pAdapter, u16 addr, u8 data, bool pseudo)
 	/*  -----------------e-fuse reg ctrl --------------------------------- */
 	/* address */
 	rtw_write8(pAdapter, EFUSE_CTRL + 1, (u8)(addr & 0xff));
+
+	error = rtw_read8(pAdapter, EFUSE_CTRL + 2, &tmp);
+	if (error)
+		return false;
+
 	rtw_write8(pAdapter, EFUSE_CTRL + 2,
-		   (rtw_read8(pAdapter, EFUSE_CTRL + 2) & 0xFC) |
+		   (tmp & 0xFC) |
 		   (u8)((addr >> 8) & 0x03));
 	rtw_write8(pAdapter, EFUSE_CTRL, data);/* data */
 
 	rtw_write8(pAdapter, EFUSE_CTRL + 3, 0xF2);/* write cmd */
 
-	while ((0x80 &  rtw_read8(pAdapter, EFUSE_CTRL + 3)) && (tmpidx < 100))
-		tmpidx++;
+	do {
+		error = rtw_read8(pAdapter, EFUSE_CTRL + 3, &tmp);
+		if (error)
+			return false;
+	} while (!(0x80 & tmp) && (++tmpidx < 100));
 
 	if (tmpidx < 100)
 		result = true;

drivers/staging/r8188eu/core/rtw_io.c

@@ -34,18 +34,15 @@ jackson@realtek.com.tw
 #define rtw_cpu_to_le16(val)		cpu_to_le16(val)
 #define rtw_cpu_to_le32(val)		cpu_to_le32(val)
 
-u8 _rtw_read8(struct adapter *adapter, u32 addr)
+int __must_check _rtw_read8(struct adapter *adapter, u32 addr, u8 *data)
 {
-	u8 r_val;
 	struct io_priv *pio_priv = &adapter->iopriv;
 	struct	intf_hdl *pintfhdl = &pio_priv->intf;
-	u8 (*_read8)(struct intf_hdl *pintfhdl, u32 addr);
-
+	int (*_read8)(struct intf_hdl *pintfhdl, u32 addr, u8 *data);
 
 	_read8 = pintfhdl->io_ops._read8;
-	r_val = _read8(pintfhdl, addr);
 
-	return r_val;
+	return _read8(pintfhdl, addr, data);
 }
 
 u16 _rtw_read16(struct adapter *adapter, u32 addr)

drivers/staging/r8188eu/core/rtw_mp.c

@@ -243,10 +243,14 @@ void GetPowerTracking(struct adapter *padapter, u8 *enable)
 static void disable_dm(struct adapter *padapter)
 {
 	u8 v8;
+	int error;
 
 	/* 3 1. disable firmware dynamic mechanism */
 	/*  disable Power Training, Rate Adaptive */
-	v8 = rtw_read8(padapter, REG_BCN_CTRL);
+	error = rtw_read8(padapter, REG_BCN_CTRL, &v8);
+	if (error)
+		return;
+
 	v8 &= ~EN_BCN_FUNCTION;
 	rtw_write8(padapter, REG_BCN_CTRL, v8);
 
@@ -363,8 +367,13 @@ s32 mp_start_test(struct adapter *padapter)
 	spin_unlock_bh(&pmlmepriv->lock);
 
 	if (res == _SUCCESS) {
+		int error;
 		/*  set MSR to WIFI_FW_ADHOC_STATE */
-		val8 = rtw_read8(padapter, MSR) & 0xFC; /*  0x0102 */
+		error = rtw_read8(padapter, MSR, &val8); /*  0x0102 */
+		if (error)
+			return _FAIL;
+
+		val8 &= 0xFC;
 		val8 |= WIFI_FW_ADHOC_STATE;
 		rtw_write8(padapter, MSR, val8); /*  Link in ad hoc network */
 	}

drivers/staging/r8188eu/core/rtw_mp_ioctl.c

@@ -632,6 +632,7 @@ int rtl8188eu_oid_rt_pro_read_register_hdl(struct oid_par_priv *poid_par_priv)
 	u32		offset, width;
 	int status = NDIS_STATUS_SUCCESS;
 	struct adapter *Adapter = (struct adapter *)(poid_par_priv->adapter_context);
+	int error;
 
 	if (poid_par_priv->type_of_oid != QUERY_OID)
 		return NDIS_STATUS_NOT_ACCEPTED;
@@ -647,7 +648,9 @@ int rtl8188eu_oid_rt_pro_read_register_hdl(struct oid_par_priv *poid_par_priv)
 
 	switch (width) {
 	case 1:
-		RegRWStruct->value = rtw_read8(Adapter, offset);
+		error = rtw_read8(Adapter, offset, (u8 *) &RegRWStruct->value);
+		if (error)
+			status = NDIS_STATUS_NOT_ACCEPTED;
 		break;
 	case 2:
 		RegRWStruct->value = rtw_read16(Adapter, offset);

drivers/staging/r8188eu/hal/HalPhyRf_8188e.c

@@ -660,8 +660,12 @@ static void _PHY_SaveMACRegisters(
 	u32 i;
 	struct hal_data_8188e	*pHalData = GET_HAL_DATA(adapt);
 	struct odm_dm_struct *dm_odm = &pHalData->odmpriv;
+	int error;
+
 	for (i = 0; i < (IQK_MAC_REG_NUM - 1); i++) {
-		MACBackup[i] = ODM_Read1Byte(dm_odm, MACReg[i]);
+		error = ODM_Read1Byte(dm_odm, MACReg[i], (u8 *) &MACBackup[i]);
+		if (error)
+			return;
 	}
 	MACBackup[i] = ODM_Read4Byte(dm_odm, MACReg[i]);
 }
@@ -1010,9 +1014,12 @@ static void phy_LCCalibrate_8188E(struct adapter *adapt, bool is2t)
 	u32 RF_Amode = 0, RF_Bmode = 0, LC_Cal;
 	struct hal_data_8188e	*pHalData = GET_HAL_DATA(adapt);
 	struct odm_dm_struct *dm_odm = &pHalData->odmpriv;
+	int error;
 
 	/* Check continuous TX and Packet TX */
-	tmpreg = ODM_Read1Byte(dm_odm, 0xd03);
+	error = ODM_Read1Byte(dm_odm, 0xd03, &tmpreg);
+	if (error)
+		return;
 
 	if ((tmpreg & 0x70) != 0)			/* Deal with contisuous TX case */
 		ODM_Write1Byte(dm_odm, 0xd03, tmpreg & 0x8F);	/* disable all continuous TX */
@@ -1232,7 +1239,13 @@ static void phy_setrfpathswitch_8188e(struct adapter *adapt, bool main, bool is2
 
 	if (!adapt->hw_init_completed) {
 		u8 u1btmp;
-		u1btmp = ODM_Read1Byte(dm_odm, REG_LEDCFG2) | BIT(7);
+		int error;
+
+		error = ODM_Read1Byte(dm_odm, REG_LEDCFG2, &u1btmp);
+		if (error)
+			return;
+
+		u1btmp |= BIT(7);
 		ODM_Write1Byte(dm_odm, REG_LEDCFG2, u1btmp);
 		ODM_SetBBReg(dm_odm, rFPGA0_XAB_RFParameter, BIT(13), 0x01);
 	}

drivers/staging/r8188eu/hal/HalPwrSeqCmd.c

@@ -35,6 +35,7 @@ u8 HalPwrSeqCmdParsing(struct adapter *padapter, u8 cut_vers, u8 fab_vers,
 	u32 offset = 0;
 	u32 poll_count = 0; /*  polling autoload done. */
 	u32 max_poll_count = 5000;
+	int error;
 
 	do {
 		pwrcfgcmd = pwrseqcmd[aryidx];
@@ -48,7 +49,9 @@ u8 HalPwrSeqCmdParsing(struct adapter *padapter, u8 cut_vers, u8 fab_vers,
 				offset = GET_PWR_CFG_OFFSET(pwrcfgcmd);
 
 				/*  Read the value from system register */
-				value = rtw_read8(padapter, offset);
+				error = rtw_read8(padapter, offset, &value);
+				if (error)
+					return false;
 
 				value &= ~(GET_PWR_CFG_MASK(pwrcfgcmd));
 				value |= (GET_PWR_CFG_VALUE(pwrcfgcmd) & GET_PWR_CFG_MASK(pwrcfgcmd));
@@ -60,7 +63,9 @@ u8 HalPwrSeqCmdParsing(struct adapter *padapter, u8 cut_vers, u8 fab_vers,
 				poll_bit = false;
 				offset = GET_PWR_CFG_OFFSET(pwrcfgcmd);
 				do {
-					value = rtw_read8(padapter, offset);
+					error = rtw_read8(padapter, offset, &value);
+					if (error)
+						return false;
 
 					value &= GET_PWR_CFG_MASK(pwrcfgcmd);
 					if (value == (GET_PWR_CFG_VALUE(pwrcfgcmd) & GET_PWR_CFG_MASK(pwrcfgcmd)))

drivers/staging/r8188eu/hal/hal_com.c

@@ -321,11 +321,14 @@ s32 c2h_evt_read(struct adapter *adapter, u8 *buf)
 	struct c2h_evt_hdr *c2h_evt;
 	int i;
 	u8 trigger;
+	int error;
 
 	if (!buf)
 		goto exit;
 
-	trigger = rtw_read8(adapter, REG_C2HEVT_CLEAR);
+	error = rtw_read8(adapter, REG_C2HEVT_CLEAR, &trigger);
+	if (error)
+		goto exit;
 
 	if (trigger == C2H_EVT_HOST_CLOSE)
 		goto exit; /* Not ready */
@@ -336,13 +339,21 @@ s32 c2h_evt_read(struct adapter *adapter, u8 *buf)
 
 	memset(c2h_evt, 0, 16);
 
-	*buf = rtw_read8(adapter, REG_C2HEVT_MSG_NORMAL);
-	*(buf + 1) = rtw_read8(adapter, REG_C2HEVT_MSG_NORMAL + 1);
+	error = rtw_read8(adapter, REG_C2HEVT_MSG_NORMAL, buf);
+	if (error)
+		goto clear_evt;
+
+	error = rtw_read8(adapter, REG_C2HEVT_MSG_NORMAL + 1, buf + 1);
+	if (error)
+		goto clear_evt;
 
 	/* Read the content */
-	for (i = 0; i < c2h_evt->plen; i++)
-		c2h_evt->payload[i] = rtw_read8(adapter, REG_C2HEVT_MSG_NORMAL +
-						sizeof(*c2h_evt) + i);
+	for (i = 0; i < c2h_evt->plen; i++) {
+		error = rtw_read8(adapter, REG_C2HEVT_MSG_NORMAL + sizeof(*c2h_evt) + i,
+				  c2h_evt->payload + i);
+		if (error)
+			goto clear_evt;
+	}
 
 	ret = _SUCCESS;
 

drivers/staging/r8188eu/hal/odm_interface.c

@@ -4,10 +4,10 @@
 #include "../include/odm_precomp.h"
 /*  ODM IO Relative API. */
 
-u8 ODM_Read1Byte(struct odm_dm_struct *pDM_Odm, u32 RegAddr)
+int ODM_Read1Byte(struct odm_dm_struct *pDM_Odm, u32 RegAddr, u8 *data)
 {
 	struct adapter *Adapter = pDM_Odm->Adapter;
-	return rtw_read8(Adapter, RegAddr);
+	return rtw_read8(Adapter, RegAddr, data);
 }
 
 u16 ODM_Read2Byte(struct odm_dm_struct *pDM_Odm, u32 RegAddr)