cxgb4: Use FW interface to get BAR0 value

Use the firmware interface to get the BAR0 value since we really don't want
to use the PCI-E Configuration Space Backdoor access which is owned by the
firmware.

Set up PCI-E Memory Window registers using the true values programmed into
BAR registers.  When the PF4 "Master Function" is exported to a Virtual
Machine, the values returned by pci_resource_start() will be for the
synthetic PCI-E Configuration Space and not the real addresses. But we need
to program the PCI-E Memory Window address decoders with the real addresses
that we're going to be using in order to have accesses through the Memory
Windows work.

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

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

4 files changed, 98 insertions, 8 deletions

diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h b/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h
index 7b5425c9c0fb..4fd215185f93 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4.h
@@ -85,7 +85,8 @@ enum {
 	MEMWIN1_BASE_T5  = 0x52000,
 	MEMWIN2_APERTURE = 65536,
 	MEMWIN2_BASE     = 0x30000,
-	MEMWIN2_BASE_T5  = 0x54000,
+	MEMWIN2_APERTURE_T5 = 131072,
+	MEMWIN2_BASE_T5  = 0x60000,
 };
 
 enum dev_master {
@@ -608,6 +609,7 @@ struct l2t_data;
 struct adapter {
 	void __iomem *regs;
 	void __iomem *bar2;
+	u32 t4_bar0;
 	struct pci_dev *pdev;
 	struct device *pdev_dev;
 	unsigned int mbox;
@@ -946,6 +948,7 @@ void t4_write_indirect(struct adapter *adap, unsigned int addr_reg,
 void t4_read_indirect(struct adapter *adap, unsigned int addr_reg,
 		      unsigned int data_reg, u32 *vals, unsigned int nregs,
 		      unsigned int start_idx);
+void t4_hw_pci_read_cfg4(struct adapter *adapter, int reg, u32 *val);
 
 struct fw_filter_wr;
 
diff --git a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
index e8e77b806c7a..524a8b2894e7 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
@@ -4773,20 +4773,75 @@ void t4_fatal_err(struct adapter *adap)
 	dev_alert(adap->pdev_dev, "encountered fatal error, adapter stopped\n");
 }
 
+/* Return the specified PCI-E Configuration Space register from our Physical
+ * Function.  We try first via a Firmware LDST Command since we prefer to let
+ * the firmware own all of these registers, but if that fails we go for it
+ * directly ourselves.
+ */
+static u32 t4_read_pcie_cfg4(struct adapter *adap, int reg)
+{
+	struct fw_ldst_cmd ldst_cmd;
+	u32 val;
+	int ret;
+
+	/* Construct and send the Firmware LDST Command to retrieve the
+	 * specified PCI-E Configuration Space register.
+	 */
+	memset(&ldst_cmd, 0, sizeof(ldst_cmd));
+	ldst_cmd.op_to_addrspace =
+		htonl(FW_CMD_OP(FW_LDST_CMD) |
+		      FW_CMD_REQUEST |
+		      FW_CMD_READ |
+		      FW_LDST_CMD_ADDRSPACE(FW_LDST_ADDRSPC_FUNC_PCIE));
+	ldst_cmd.cycles_to_len16 = htonl(FW_LEN16(ldst_cmd));
+	ldst_cmd.u.pcie.select_naccess = FW_LDST_CMD_NACCESS(1);
+	ldst_cmd.u.pcie.ctrl_to_fn =
+		(FW_LDST_CMD_LC | FW_LDST_CMD_FN(adap->fn));
+	ldst_cmd.u.pcie.r = reg;
+	ret = t4_wr_mbox(adap, adap->mbox, &ldst_cmd, sizeof(ldst_cmd),
+			 &ldst_cmd);
+
+	/* If the LDST Command suucceeded, exctract the returned register
+	 * value.  Otherwise read it directly ourself.
+	 */
+	if (ret == 0)
+		val = ntohl(ldst_cmd.u.pcie.data[0]);
+	else
+		t4_hw_pci_read_cfg4(adap, reg, &val);
+
+	return val;
+}
+
 static void setup_memwin(struct adapter *adap)
 {
-	u32 bar0, mem_win0_base, mem_win1_base, mem_win2_base;
+	u32 mem_win0_base, mem_win1_base, mem_win2_base, mem_win2_aperture;
 
-	bar0 = pci_resource_start(adap->pdev, 0);  /* truncation intentional */
 	if (is_t4(adap->params.chip)) {
+		u32 bar0;
+
+		/* Truncation intentional: we only read the bottom 32-bits of
+		 * the 64-bit BAR0/BAR1 ...  We use the hardware backdoor
+		 * mechanism to read BAR0 instead of using
+		 * pci_resource_start() because we could be operating from
+		 * within a Virtual Machine which is trapping our accesses to
+		 * our Configuration Space and we need to set up the PCI-E
+		 * Memory Window decoders with the actual addresses which will
+		 * be coming across the PCI-E link.
+		 */
+		bar0 = t4_read_pcie_cfg4(adap, PCI_BASE_ADDRESS_0);
+		bar0 &= PCI_BASE_ADDRESS_MEM_MASK;
+		adap->t4_bar0 = bar0;
+
 		mem_win0_base = bar0 + MEMWIN0_BASE;
 		mem_win1_base = bar0 + MEMWIN1_BASE;
 		mem_win2_base = bar0 + MEMWIN2_BASE;
+		mem_win2_aperture = MEMWIN2_APERTURE;
 	} else {
 		/* For T5, only relative offset inside the PCIe BAR is passed */
 		mem_win0_base = MEMWIN0_BASE;
-		mem_win1_base = MEMWIN1_BASE_T5;
+		mem_win1_base = MEMWIN1_BASE;
 		mem_win2_base = MEMWIN2_BASE_T5;
+		mem_win2_aperture = MEMWIN2_APERTURE_T5;
 	}
 	t4_write_reg(adap, PCIE_MEM_ACCESS_REG(PCIE_MEM_ACCESS_BASE_WIN, 0),
 		     mem_win0_base | BIR(0) |
@@ -4796,16 +4851,19 @@ static void setup_memwin(struct adapter *adap)
 		     WINDOW(ilog2(MEMWIN1_APERTURE) - 10));
 	t4_write_reg(adap, PCIE_MEM_ACCESS_REG(PCIE_MEM_ACCESS_BASE_WIN, 2),
 		     mem_win2_base | BIR(0) |
-		     WINDOW(ilog2(MEMWIN2_APERTURE) - 10));
+		     WINDOW(ilog2(mem_win2_aperture) - 10));
+	t4_read_reg(adap, PCIE_MEM_ACCESS_REG(PCIE_MEM_ACCESS_BASE_WIN, 2));
 }
 
 static void setup_memwin_rdma(struct adapter *adap)
 {
 	if (adap->vres.ocq.size) {
-		unsigned int start, sz_kb;
+		u32 start;
+		unsigned int sz_kb;
 
-		start = pci_resource_start(adap->pdev, 2) +
-			OCQ_WIN_OFFSET(adap->pdev, &adap->vres);
+		start = t4_read_pcie_cfg4(adap, PCI_BASE_ADDRESS_2);
+		start &= PCI_BASE_ADDRESS_MEM_MASK;
+		start += OCQ_WIN_OFFSET(adap->pdev, &adap->vres);
 		sz_kb = roundup_pow_of_two(adap->vres.ocq.size) >> 10;
 		t4_write_reg(adap,
 			     PCIE_MEM_ACCESS_REG(PCIE_MEM_ACCESS_BASE_WIN, 3),
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
index 4536ea9f7018..2c3d00d77ef6 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c
@@ -144,6 +144,30 @@ void t4_write_indirect(struct adapter *adap, unsigned int addr_reg,
 }
 
 /*
+ * Read a 32-bit PCI Configuration Space register via the PCI-E backdoor
+ * mechanism.  This guarantees that we get the real value even if we're
+ * operating within a Virtual Machine and the Hypervisor is trapping our
+ * Configuration Space accesses.
+ */
+void t4_hw_pci_read_cfg4(struct adapter *adap, int reg, u32 *val)
+{
+	u32 req = ENABLE | FUNCTION(adap->fn) | reg;
+
+	if (is_t4(adap->params.chip))
+		req |= F_LOCALCFG;
+
+	t4_write_reg(adap, PCIE_CFG_SPACE_REQ, req);
+	*val = t4_read_reg(adap, PCIE_CFG_SPACE_DATA);
+
+	/* Reset ENABLE to 0 so reads of PCIE_CFG_SPACE_DATA won't cause a
+	 * Configuration Space read.  (None of the other fields matter when
+	 * ENABLE is 0 so a simple register write is easier than a
+	 * read-modify-write via t4_set_reg_field().)
+	 */
+	t4_write_reg(adap, PCIE_CFG_SPACE_REQ, 0);
+}
+
+/*
  * Get the reply to a mailbox command and store it in @rpl in big-endian order.
  */
 static void get_mbox_rpl(struct adapter *adap, __be64 *rpl, int nflit,
diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h b/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h
index 3360025ad922..f6b2ee13e715 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h
+++ b/drivers/net/ethernet/chelsio/cxgb4/t4_regs.h
@@ -387,6 +387,8 @@
 #define  MSTGRPPERR      0x00000001U
 
 #define PCIE_NONFAT_ERR 0x3010
+#define PCIE_CFG_SPACE_REQ 0x3060
+#define PCIE_CFG_SPACE_DATA 0x3064
 #define PCIE_MEM_ACCESS_BASE_WIN 0x3068
 #define S_PCIEOFST       10
 #define M_PCIEOFST       0x3fffffU
@@ -399,6 +401,9 @@
 #define  WINDOW_SHIFT    0
 #define  WINDOW(x)       ((x) << WINDOW_SHIFT)
 #define PCIE_MEM_ACCESS_OFFSET 0x306c
+#define ENABLE	(1U << 30)
+#define FUNCTION(x) ((x) << 12)
+#define F_LOCALCFG    (1U << 28)
 
 #define S_PFNUM    0
 #define V_PFNUM(x) ((x) << S_PFNUM)