cxgb4: Fix to dump devlog, even if FW is crashed

Add new Common Code routines to retrieve Firmware Device Log
parameters from PCIE_FW_PF[7]. The firmware initializes its Device Log very
early on and stores the parameters for its location/size in that register.
Using the parameters from the register allows us to access the Firmware
Device Log even when the firmware crashes very early on or we're not
attached to the firmware

Based on original work by Casey Leedom <leedom@chelsio.com>

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cxgb4.h

@@ -1136,6 +1136,8 @@ int cxgb4_t4_bar2_sge_qregs(struct adapter *adapter,
 
 unsigned int qtimer_val(const struct adapter *adap,
 			const struct sge_rspq *q);
+
+int t4_init_devlog_params(struct adapter *adapter);
 int t4_init_sge_params(struct adapter *adapter);
 int t4_init_tp_params(struct adapter *adap);
 int t4_filter_field_shift(const struct adapter *adap, int filter_sel);

drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c

@@ -5110,10 +5110,15 @@ static int adap_init0(struct adapter *adap)
 	enum dev_state state;
 	u32 params[7], val[7];
 	struct fw_caps_config_cmd caps_cmd;
-	struct fw_devlog_cmd devlog_cmd;
-	u32 devlog_meminfo;
 	int reset = 1;
 
+	/* Grab Firmware Device Log parameters as early as possible so we have
+	 * access to it for debugging, etc.
+	 */
+	ret = t4_init_devlog_params(adap);
+	if (ret < 0)
+		return ret;
+
 	/* Contact FW, advertising Master capability */
 	ret = t4_fw_hello(adap, adap->mbox, adap->mbox, MASTER_MAY, &state);
 	if (ret < 0) {
@@ -5191,30 +5196,6 @@ static int adap_init0(struct adapter *adap)
 	if (ret < 0)
 		goto bye;
 
-	/* Read firmware device log parameters.  We really need to find a way
-	 * to get these parameters initialized with some default values (which
-	 * are likely to be correct) for the case where we either don't
-	 * attache to the firmware or it's crashed when we probe the adapter.
-	 * That way we'll still be able to perform early firmware startup
-	 * debugging ...  If the request to get the Firmware's Device Log
-	 * parameters fails, we'll live so we don't make that a fatal error.
-	 */
-	memset(&devlog_cmd, 0, sizeof(devlog_cmd));
-	devlog_cmd.op_to_write = htonl(FW_CMD_OP_V(FW_DEVLOG_CMD) |
-				       FW_CMD_REQUEST_F | FW_CMD_READ_F);
-	devlog_cmd.retval_len16 = htonl(FW_LEN16(devlog_cmd));
-	ret = t4_wr_mbox(adap, adap->mbox, &devlog_cmd, sizeof(devlog_cmd),
-			 &devlog_cmd);
-	if (ret == 0) {
-		devlog_meminfo =
-			ntohl(devlog_cmd.memtype_devlog_memaddr16_devlog);
-		adap->params.devlog.memtype =
-			FW_DEVLOG_CMD_MEMTYPE_DEVLOG_G(devlog_meminfo);
-		adap->params.devlog.start =
-			FW_DEVLOG_CMD_MEMADDR16_DEVLOG_G(devlog_meminfo) << 4;
-		adap->params.devlog.size = ntohl(devlog_cmd.memsize_devlog);
-	}
-
 	/*
 	 * Find out what ports are available to us.  Note that we need to do
 	 * this before calling adap_init0_no_config() since it needs nports

drivers/net/ethernet/chelsio/cxgb4/t4_hw.c

@@ -4458,6 +4458,59 @@ int cxgb4_t4_bar2_sge_qregs(struct adapter *adapter,
 	return 0;
 }
 
+/**
+ *	t4_init_devlog_params - initialize adapter->params.devlog
+ *	@adap: the adapter
+ *
+ *	Initialize various fields of the adapter's Firmware Device Log
+ *	Parameters structure.
+ */
+int t4_init_devlog_params(struct adapter *adap)
+{
+	struct devlog_params *dparams = &adap->params.devlog;
+	u32 pf_dparams;
+	unsigned int devlog_meminfo;
+	struct fw_devlog_cmd devlog_cmd;
+	int ret;
+
+	/* If we're dealing with newer firmware, the Device Log Paramerters
+	 * are stored in a designated register which allows us to access the
+	 * Device Log even if we can't talk to the firmware.
+	 */
+	pf_dparams =
+		t4_read_reg(adap, PCIE_FW_REG(PCIE_FW_PF_A, PCIE_FW_PF_DEVLOG));
+	if (pf_dparams) {
+		unsigned int nentries, nentries128;
+
+		dparams->memtype = PCIE_FW_PF_DEVLOG_MEMTYPE_G(pf_dparams);
+		dparams->start = PCIE_FW_PF_DEVLOG_ADDR16_G(pf_dparams) << 4;
+
+		nentries128 = PCIE_FW_PF_DEVLOG_NENTRIES128_G(pf_dparams);
+		nentries = (nentries128 + 1) * 128;
+		dparams->size = nentries * sizeof(struct fw_devlog_e);
+
+		return 0;
+	}
+
+	/* Otherwise, ask the firmware for it's Device Log Parameters.
+	 */
+	memset(&devlog_cmd, 0, sizeof(devlog_cmd));
+	devlog_cmd.op_to_write = htonl(FW_CMD_OP_V(FW_DEVLOG_CMD) |
+				       FW_CMD_REQUEST_F | FW_CMD_READ_F);
+	devlog_cmd.retval_len16 = htonl(FW_LEN16(devlog_cmd));
+	ret = t4_wr_mbox(adap, adap->mbox, &devlog_cmd, sizeof(devlog_cmd),
+			 &devlog_cmd);
+	if (ret)
+		return ret;
+
+	devlog_meminfo = ntohl(devlog_cmd.memtype_devlog_memaddr16_devlog);
+	dparams->memtype = FW_DEVLOG_CMD_MEMTYPE_DEVLOG_G(devlog_meminfo);
+	dparams->start = FW_DEVLOG_CMD_MEMADDR16_DEVLOG_G(devlog_meminfo) << 4;
+	dparams->size = ntohl(devlog_cmd.memsize_devlog);
+
+	return 0;
+}
+
 /**
  *	t4_init_sge_params - initialize adap->params.sge
  *	@adapter: the adapter

drivers/net/ethernet/chelsio/cxgb4/t4_regs.h

@@ -63,6 +63,8 @@
 #define MC_BIST_STATUS_REG(reg_addr, idx) ((reg_addr) + (idx) * 4)
 #define EDC_BIST_STATUS_REG(reg_addr, idx) ((reg_addr) + (idx) * 4)
 
+#define PCIE_FW_REG(reg_addr, idx) ((reg_addr) + (idx) * 4)
+
 #define SGE_PF_KDOORBELL_A 0x0
 
 #define QID_S    15
@@ -707,6 +709,7 @@
 #define PFNUM_V(x) ((x) << PFNUM_S)
 
 #define PCIE_FW_A 0x30b8
+#define PCIE_FW_PF_A 0x30bc
 
 #define PCIE_CORE_UTL_SYSTEM_BUS_AGENT_STATUS_A 0x5908