qed: Don't use main-ptt in unrelated flows

In order to access HW registers driver needs to acquire a PTT entry
[mapping between bar memory and internal chip address].
Since acquiring PTT entries could fail [at least in theory] as their
number is finite and other flows can hold them, we reserve special PTT
entries for 'important' enough flows - ones we want to guarantee that
would not be susceptible to such issues.

One such special entry is the 'main' PTT which is meant to be used in
flows such as chip initialization and de-initialization.
However, there are other flows that are also using that same entry
for their own purpose, and might run concurrently with the original
flows [notice that for most cases using the main-ptt by mistake, such
a race is still impossible, at least today].

This patch re-organizes the various functions that currently use the
main_ptt in one of two ways:

  - If a function shouldn't use the main_ptt it starts acquiring and
    releasing it's own PTT entry and use it instead. Notice if those
    functions previously couldn't fail, they now can [as acquisition
    might fail].

  - Change the prototypes so that the main_ptt would be received as
    a parameter [instead of explicitly accessing it].
    This prevents the future risk of adding codes that introduces new
    use-cases for flows using the main_ptt, ones that might be in race
    with the actual 'main' flows.

Signed-off-by: Rahul Verma <Rahul.Verma@cavium.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 41 insertions, 26 deletions

diff --git a/drivers/net/ethernet/qlogic/qed/qed_dev.c b/drivers/net/ethernet/qlogic/qed/qed_dev.c
index 249878533fd9..2df83be3ccf0 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_dev.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_dev.c
@@ -75,7 +75,8 @@ enum BAR_ID {
 	BAR_ID_1        /* Used for doorbells */
 };
 
-static u32 qed_hw_bar_size(struct qed_hwfn *p_hwfn, enum BAR_ID bar_id)
+static u32 qed_hw_bar_size(struct qed_hwfn *p_hwfn,
+			   struct qed_ptt *p_ptt, enum BAR_ID bar_id)
 {
 	u32 bar_reg = (bar_id == BAR_ID_0 ?
 		       PGLUE_B_REG_PF_BAR0_SIZE : PGLUE_B_REG_PF_BAR1_SIZE);
@@ -84,7 +85,7 @@ static u32 qed_hw_bar_size(struct qed_hwfn *p_hwfn, enum BAR_ID bar_id)
 	if (IS_VF(p_hwfn->cdev))
 		return 1 << 17;
 
-	val = qed_rd(p_hwfn, p_hwfn->p_main_ptt, bar_reg);
+	val = qed_rd(p_hwfn, p_ptt, bar_reg);
 	if (val)
 		return 1 << (val + 15);
 
@@ -780,7 +781,7 @@ int qed_qm_reconf(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 	qed_init_clear_rt_data(p_hwfn);
 
 	/* prepare QM portion of runtime array */
-	qed_qm_init_pf(p_hwfn);
+	qed_qm_init_pf(p_hwfn, p_ptt);
 
 	/* activate init tool on runtime array */
 	rc = qed_init_run(p_hwfn, p_ptt, PHASE_QM_PF, p_hwfn->rel_pf_id,
@@ -1320,7 +1321,7 @@ qed_hw_init_pf_doorbell_bar(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 	int rc = 0;
 	u8 cond;
 
-	db_bar_size = qed_hw_bar_size(p_hwfn, BAR_ID_1);
+	db_bar_size = qed_hw_bar_size(p_hwfn, p_ptt, BAR_ID_1);
 	if (p_hwfn->cdev->num_hwfns > 1)
 		db_bar_size /= 2;
 
@@ -1431,7 +1432,7 @@ static int qed_hw_init_pf(struct qed_hwfn *p_hwfn,
 		p_hwfn->qm_info.pf_rl = 100000;
 	}
 
-	qed_cxt_hw_init_pf(p_hwfn);
+	qed_cxt_hw_init_pf(p_hwfn, p_ptt);
 
 	qed_int_igu_init_rt(p_hwfn);
 
@@ -1852,18 +1853,21 @@ int qed_hw_stop(struct qed_dev *cdev)
 	return rc2;
 }
 
-void qed_hw_stop_fastpath(struct qed_dev *cdev)
+int qed_hw_stop_fastpath(struct qed_dev *cdev)
 {
 	int j;
 
 	for_each_hwfn(cdev, j) {
 		struct qed_hwfn *p_hwfn = &cdev->hwfns[j];
-		struct qed_ptt *p_ptt = p_hwfn->p_main_ptt;
+		struct qed_ptt *p_ptt;
 
 		if (IS_VF(cdev)) {
 			qed_vf_pf_int_cleanup(p_hwfn);
 			continue;
 		}
+		p_ptt = qed_ptt_acquire(p_hwfn);
+		if (!p_ptt)
+			return -EAGAIN;
 
 		DP_VERBOSE(p_hwfn,
 			   NETIF_MSG_IFDOWN, "Shutting down the fastpath\n");
@@ -1881,17 +1885,28 @@ void qed_hw_stop_fastpath(struct qed_dev *cdev)
 
 		/* Need to wait 1ms to guarantee SBs are cleared */
 		usleep_range(1000, 2000);
+		qed_ptt_release(p_hwfn, p_ptt);
 	}
+
+	return 0;
 }
 
-void qed_hw_start_fastpath(struct qed_hwfn *p_hwfn)
+int qed_hw_start_fastpath(struct qed_hwfn *p_hwfn)
 {
+	struct qed_ptt *p_ptt;
+
 	if (IS_VF(p_hwfn->cdev))
-		return;
+		return 0;
+
+	p_ptt = qed_ptt_acquire(p_hwfn);
+	if (!p_ptt)
+		return -EAGAIN;
 
 	/* Re-open incoming traffic */
-	qed_wr(p_hwfn, p_hwfn->p_main_ptt,
-	       NIG_REG_RX_LLH_BRB_GATE_DNTFWD_PERPF, 0x0);
+	qed_wr(p_hwfn, p_ptt, NIG_REG_RX_LLH_BRB_GATE_DNTFWD_PERPF, 0x0);
+	qed_ptt_release(p_hwfn, p_ptt);
+
+	return 0;
 }
 
 /* Free hwfn memory and resources acquired in hw_hwfn_prepare */
@@ -2697,9 +2712,9 @@ qed_get_hw_info(struct qed_hwfn *p_hwfn,
 	return qed_hw_get_resc(p_hwfn, p_ptt);
 }
 
-static int qed_get_dev_info(struct qed_dev *cdev)
+static int qed_get_dev_info(struct qed_hwfn *p_hwfn, struct qed_ptt *p_ptt)
 {
-	struct qed_hwfn *p_hwfn = QED_LEADING_HWFN(cdev);
+	struct qed_dev *cdev = p_hwfn->cdev;
 	u16 device_id_mask;
 	u32 tmp;
 
@@ -2721,15 +2736,13 @@ static int qed_get_dev_info(struct qed_dev *cdev)
 		return -EBUSY;
 	}
 
-	cdev->chip_num = (u16)qed_rd(p_hwfn, p_hwfn->p_main_ptt,
-				     MISCS_REG_CHIP_NUM);
-	cdev->chip_rev = (u16)qed_rd(p_hwfn, p_hwfn->p_main_ptt,
-				     MISCS_REG_CHIP_REV);
+	cdev->chip_num = (u16)qed_rd(p_hwfn, p_ptt, MISCS_REG_CHIP_NUM);
+	cdev->chip_rev = (u16)qed_rd(p_hwfn, p_ptt, MISCS_REG_CHIP_REV);
+
 	MASK_FIELD(CHIP_REV, cdev->chip_rev);
 
 	/* Learn number of HW-functions */
-	tmp = qed_rd(p_hwfn, p_hwfn->p_main_ptt,
-		     MISCS_REG_CMT_ENABLED_FOR_PAIR);
+	tmp = qed_rd(p_hwfn, p_ptt, MISCS_REG_CMT_ENABLED_FOR_PAIR);
 
 	if (tmp & (1 << p_hwfn->rel_pf_id)) {
 		DP_NOTICE(cdev->hwfns, "device in CMT mode\n");
@@ -2738,11 +2751,10 @@ static int qed_get_dev_info(struct qed_dev *cdev)
 		cdev->num_hwfns = 1;
 	}
 
-	cdev->chip_bond_id = qed_rd(p_hwfn, p_hwfn->p_main_ptt,
+	cdev->chip_bond_id = qed_rd(p_hwfn, p_ptt,
 				    MISCS_REG_CHIP_TEST_REG) >> 4;
 	MASK_FIELD(CHIP_BOND_ID, cdev->chip_bond_id);
-	cdev->chip_metal = (u16)qed_rd(p_hwfn, p_hwfn->p_main_ptt,
-				       MISCS_REG_CHIP_METAL);
+	cdev->chip_metal = (u16)qed_rd(p_hwfn, p_ptt, MISCS_REG_CHIP_METAL);
 	MASK_FIELD(CHIP_METAL, cdev->chip_metal);
 
 	DP_INFO(cdev->hwfns,
@@ -2795,7 +2807,7 @@ static int qed_hw_prepare_single(struct qed_hwfn *p_hwfn,
 
 	/* First hwfn learns basic information, e.g., number of hwfns */
 	if (!p_hwfn->my_id) {
-		rc = qed_get_dev_info(p_hwfn->cdev);
+		rc = qed_get_dev_info(p_hwfn, p_hwfn->p_main_ptt);
 		if (rc)
 			goto err1;
 	}
@@ -2866,11 +2878,14 @@ int qed_hw_prepare(struct qed_dev *cdev,
 		u8 __iomem *addr;
 
 		/* adjust bar offset for second engine */
-		addr = cdev->regview + qed_hw_bar_size(p_hwfn, BAR_ID_0) / 2;
+		addr = cdev->regview +
+		       qed_hw_bar_size(p_hwfn, p_hwfn->p_main_ptt,
+				       BAR_ID_0) / 2;
 		p_regview = addr;
 
-		/* adjust doorbell bar offset for second engine */
-		addr = cdev->doorbells + qed_hw_bar_size(p_hwfn, BAR_ID_1) / 2;
+		addr = cdev->doorbells +
+		       qed_hw_bar_size(p_hwfn, p_hwfn->p_main_ptt,
+				       BAR_ID_1) / 2;
 		p_doorbell = addr;
 
 		/* prepare second hw function */