[PATCH 3.19 032/175] rtlwifi: rtl8192ee: Fix DMA stalls

Greg Kroah-Hartman
2015-03-04T06:19:48Z

From: Troy Tan <troy_tan@realsil.com.cn>

commit 21b39ddb5bb2294fe64fbd29045591fe0707825f upstream.

There are instances where the DMA engine stalls. The new code detects
such stalls and restarts DMA without needing a power reset.

Signed-off-by: Troy Tan <troy_tan@realsil.com.cn>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/rtlwifi/rtl8192ee/hw.c | 140 +++++++++++++++++++++++++++
drivers/net/wireless/rtlwifi/rtl8192ee/reg.h | 2
2 files changed, 142 insertions(+)

--- a/drivers/net/wireless/rtlwifi/rtl8192ee/hw.c
+++ b/drivers/net/wireless/rtlwifi/rtl8192ee/hw.c
@@ -1137,6 +1137,139 @@ void rtl92ee_enable_hw_security_config(s
rtlpriv->cfg->ops->set_hw_reg(hw, HW_VAR_WPA_CONFIG, &sec_reg_value);
}

+static bool _rtl8192ee_check_pcie_dma_hang(struct rtl_priv *rtlpriv)
+{
+ u8 tmp;
+
+ /* write reg 0x350 Bit[26]=1. Enable debug port. */
+ tmp = rtl_read_byte(rtlpriv, REG_BACKDOOR_DBI_DATA + 3);
+ if (!(tmp & BIT(2))) {
+ rtl_write_byte(rtlpriv, REG_BACKDOOR_DBI_DATA + 3,
+ tmp | BIT(2));
+ mdelay(100); /* Suggested by DD Justin_tsai. */
+ }
+
+ /* read reg 0x350 Bit[25] if 1 : RX hang
+ * read reg 0x350 Bit[24] if 1 : TX hang
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_BACKDOOR_DBI_DATA + 3);
+ if ((tmp & BIT(0)) || (tmp & BIT(1))) {
+ RT_TRACE(rtlpriv, COMP_INIT, DBG_LOUD,
+ "CheckPcieDMAHang8192EE(): true!!\n");
+ return true;
+ }
+ return false;
+}
+
+static void _rtl8192ee_reset_pcie_interface_dma(struct rtl_priv *rtlpriv,
+ bool mac_power_on)
+{
+ u8 tmp;
+ bool release_mac_rx_pause;
+ u8 backup_pcie_dma_pause;
+
+ RT_TRACE(rtlpriv, COMP_INIT, DBG_LOUD,
+ "ResetPcieInterfaceDMA8192EE()\n");
+
+ /* Revise Note: Follow the document "PCIe RX DMA Hang Reset Flow_v03"
+ * released by SD1 Alan.
+ */
+
+ /* 1. disable register write lock
+ * write 0x1C bit[1:0] = 2'h0
+ * write 0xCC bit[2] = 1'b1
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_RSV_CTRL);
+ tmp &= ~(BIT(1) | BIT(0));
+ rtl_write_byte(rtlpriv, REG_RSV_CTRL, tmp);
+ tmp = rtl_read_byte(rtlpriv, REG_PMC_DBG_CTRL2);
+ tmp |= BIT(2);
+ rtl_write_byte(rtlpriv, REG_PMC_DBG_CTRL2, tmp);
+
+ /* 2. Check and pause TRX DMA
+ * write 0x284 bit[18] = 1'b1
+ * write 0x301 = 0xFF
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_RXDMA_CONTROL);
+ if (tmp & BIT(2)) {
+ /* Already pause before the function for another reason. */
+ release_mac_rx_pause = false;
+ } else {
+ rtl_write_byte(rtlpriv, REG_RXDMA_CONTROL, (tmp | BIT(2)));
+ release_mac_rx_pause = true;
+ }
+
+ backup_pcie_dma_pause = rtl_read_byte(rtlpriv, REG_PCIE_CTRL_REG + 1);
+ if (backup_pcie_dma_pause != 0xFF)
+ rtl_write_byte(rtlpriv, REG_PCIE_CTRL_REG + 1, 0xFF);
+
+ if (mac_power_on) {
+ /* 3. reset TRX function
+ * write 0x100 = 0x00
+ */
+ rtl_write_byte(rtlpriv, REG_CR, 0);
+ }
+
+ /* 4. Reset PCIe DMA
+ * write 0x003 bit[0] = 0
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_SYS_FUNC_EN + 1);
+ tmp &= ~(BIT(0));
+ rtl_write_byte(rtlpriv, REG_SYS_FUNC_EN + 1, tmp);
+
+ /* 5. Enable PCIe DMA
+ * write 0x003 bit[0] = 1
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_SYS_FUNC_EN + 1);
+ tmp |= BIT(0);
+ rtl_write_byte(rtlpriv, REG_SYS_FUNC_EN + 1, tmp);
+
+ if (mac_power_on) {
+ /* 6. enable TRX function
+ * write 0x100 = 0xFF
+ */
+ rtl_write_byte(rtlpriv, REG_CR, 0xFF);
+
+ /* We should init LLT & RQPN and
+ * prepare Tx/Rx descrptor address later
+ * because MAC function is reset.
+ */
+ }
+
+ /* 7. Restore PCIe autoload down bit
+ * write 0xF8 bit[17] = 1'b1
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_MAC_PHY_CTRL_NORMAL + 2);
+ tmp |= BIT(1);
+ rtl_write_byte(rtlpriv, REG_MAC_PHY_CTRL_NORMAL + 2, tmp);
+
+ /* In MAC power on state, BB and RF maybe in ON state,
+ * if we release TRx DMA here
+ * it will cause packets to be started to Tx/Rx,
+ * so we release Tx/Rx DMA later.
+ */
+ if (!mac_power_on) {
+ /* 8. release TRX DMA
+ * write 0x284 bit[18] = 1'b0
+ * write 0x301 = 0x00
+ */
+ if (release_mac_rx_pause) {
+ tmp = rtl_read_byte(rtlpriv, REG_RXDMA_CONTROL);
+ rtl_write_byte(rtlpriv, REG_RXDMA_CONTROL,
+ (tmp & (~BIT(2))));
+ }
+ rtl_write_byte(rtlpriv, REG_PCIE_CTRL_REG + 1,
+ backup_pcie_dma_pause);
+ }
+
+ /* 9. lock system register
+ * write 0xCC bit[2] = 1'b0
+ */
+ tmp = rtl_read_byte(rtlpriv, REG_PMC_DBG_CTRL2);
+ tmp &= ~(BIT(2));
+ rtl_write_byte(rtlpriv, REG_PMC_DBG_CTRL2, tmp);
+}
+
int rtl92ee_hw_init(struct ieee80211_hw *hw)
{
struct rtl_priv *rtlpriv = rtl_priv(hw);
@@ -1162,6 +1295,13 @@ int rtl92ee_hw_init(struct ieee80211_hw
rtlhal->fw_ps_state = FW_PS_STATE_ALL_ON_92E;
}

+ if (_rtl8192ee_check_pcie_dma_hang(rtlpriv)) {
+ RT_TRACE(rtlpriv, COMP_INIT, DBG_DMESG, "92ee dma hang!\n");
+ _rtl8192ee_reset_pcie_interface_dma(rtlpriv,
+ rtlhal->mac_func_enable);
+ rtlhal->mac_func_enable = false;
+ }
+
rtstatus = _rtl92ee_init_mac(hw);

rtl_write_byte(rtlpriv, 0x577, 0x03);
--- a/drivers/net/wireless/rtlwifi/rtl8192ee/reg.h
+++ b/drivers/net/wireless/rtlwifi/rtl8192ee/reg.h
@@ -77,9 +77,11 @@
#define REG_HIMRE 0x00B8
#define REG_HISRE 0x00BC

+#define REG_PMC_DBG_CTRL2 0x00CC
#define REG_EFUSE_ACCESS 0x00CF
#define REG_HPON_FSM 0x00EC
#define REG_SYS_CFG1 0x00F0
+#define REG_MAC_PHY_CTRL_NORMAL 0x00F8
#define REG_SYS_CFG2 0x00FC

#define REG_CR 0x0100