Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   "Kalluru, Sudarsana" <Sudarsana.Kalluru@cavium.com>
To:     Sinan Kaya <okaya@codeaurora.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        "timur@codeaurora.org" <timur@codeaurora.org>,
        "sulrich@codeaurora.org" <sulrich@codeaurora.org>
CC:     "linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "Elior, Ariel" <Ariel.Elior@cavium.com>,
        Dept-Eng Everest Linux L2 <Dept-EngEverestLinuxL2@cavium.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v4 11/17] bnx2x: Eliminate duplicate barriers on
 weakly-ordered archs
Thread-Topic: [PATCH v4 11/17] bnx2x: Eliminate duplicate barriers on
 weakly-ordered archs
Thread-Index: AQHTv/UuglsGnACU/UerdhYYJENqWqPcC+bg
Date:   Thu, 22 Mar 2018 10:10:04 +0000
Message-ID: <MW2PR07MB41398F91AC59C01EBA46E5B78AA90@MW2PR07MB4139.namprd07.prod.outlook.com>
References: <1521513753-7325-1-git-send-email-okaya@codeaurora.org>
 <1521513753-7325-12-git-send-email-okaya@codeaurora.org>
In-Reply-To: <1521513753-7325-12-git-send-email-okaya@codeaurora.org>
Accept-Language: en-IN, en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: cavium.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 4105fa08-b78f-48c2-b5f1-08d58fdd14d6
X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Mar 2018 10:10:04.1859
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 711e4ccf-2e9b-4bcf-a551-4094005b6194
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW2PR07MB4073
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

-----Original Message-----
From: Sinan Kaya [mailto:okaya@codeaurora.org]=20
Sent: 20 March 2018 08:12
To: netdev@vger.kernel.org; timur@codeaurora.org; sulrich@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org; linux-arm-kernel@lists.infradead.org; Si=
nan Kaya <okaya@codeaurora.org>; Elior, Ariel <Ariel.Elior@cavium.com>; Dep=
t-Eng Everest Linux L2 <Dept-EngEverestLinuxL2@cavium.com>; linux-kernel@vg=
er.kernel.org
Subject: [PATCH v4 11/17] bnx2x: Eliminate duplicate barriers on weakly-ord=
ered archs

Code includes wmb() followed by writel(). writel() already has a barrier on=
 some architectures like arm64.

This ends up CPU observing two barriers back to back before executing the r=
egister write.

Since code already has an explicit barrier call, changing writel() to write=
l_relaxed().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x.h       |  9 ++++++++-
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h   |  4 ++--
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c  | 21 +++++++++++--------=
--  drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c |  2 +-  drivers/net/=
ethernet/broadcom/bnx2x/bnx2x_vfpf.c  |  2 +-
 5 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethe=
rnet/broadcom/bnx2x/bnx2x.h
index 352beff..ac38db9 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
@@ -166,6 +166,12 @@ do {						\
 #define REG_RD8(bp, offset)		readb(REG_ADDR(bp, offset))
 #define REG_RD16(bp, offset)		readw(REG_ADDR(bp, offset))
=20
+#define REG_WR_RELAXED(bp, offset, val)	writel_relaxed((u32)val,\
+						       REG_ADDR(bp, offset))
+
+#define REG_WR16_RELAXED(bp, offset, val) \
+	writew_relaxed((u16)val, REG_ADDR(bp, offset))
+
 #define REG_WR(bp, offset, val)		writel((u32)val, REG_ADDR(bp, offset))
 #define REG_WR8(bp, offset, val)	writeb((u8)val, REG_ADDR(bp, offset))
 #define REG_WR16(bp, offset, val)	writew((u16)val, REG_ADDR(bp, offset))
@@ -760,7 +766,8 @@ struct bnx2x_fastpath {  #endif  #define DOORBELL(bp, c=
id, val) \
 	do { \
-		writel((u32)(val), bp->doorbells + (bp->db_size * (cid))); \
+		writel_relaxed((u32)(val),\
+				bp->doorbells + (bp->db_size * (cid))); \
 	} while (0)
=20
 /* TX CSUM helpers */
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h b/drivers/net/=
ethernet/broadcom/bnx2x/bnx2x_cmn.h
index a5265e1..a8ce5c5 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
@@ -522,8 +522,8 @@ static inline void bnx2x_update_rx_prod(struct bnx2x *b=
p,
 	wmb();
=20
 	for (i =3D 0; i < sizeof(rx_prods)/4; i++)
-		REG_WR(bp, fp->ustorm_rx_prods_offset + i*4,
-		       ((u32 *)&rx_prods)[i]);
+		REG_WR_RELAXED(bp, fp->ustorm_rx_prods_offset + i * 4,
+			       ((u32 *)&rx_prods)[i]);
=20
 	mmiowb(); /* keep prod updates ordered */
=20
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c b/drivers/net=
/ethernet/broadcom/bnx2x/bnx2x_main.c
index 74fc9af..2dea1b6 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c
@@ -1608,8 +1608,8 @@ static void bnx2x_hc_int_enable(struct bnx2x *bp)
 		} else
 			val =3D 0xffff;
=20
-		REG_WR(bp, HC_REG_TRAILING_EDGE_0 + port*8, val);
-		REG_WR(bp, HC_REG_LEADING_EDGE_0 + port*8, val);
+		REG_WR_RELAXED(bp, HC_REG_TRAILING_EDGE_0 + port * 8, val);
+		REG_WR_RELAXED(bp, HC_REG_LEADING_EDGE_0 + port * 8, val);
 	}
=20
 	/* Make sure that interrupts are indeed enabled from here on */ @@ -1672,=
8 +1672,8 @@ static void bnx2x_igu_int_enable(struct bnx2x *bp)
 	} else
 		val =3D 0xffff;
=20
-	REG_WR(bp, IGU_REG_TRAILING_EDGE_LATCH, val);
-	REG_WR(bp, IGU_REG_LEADING_EDGE_LATCH, val);
+	REG_WR_RELAXED(bp, IGU_REG_TRAILING_EDGE_LATCH, val);
+	REG_WR_RELAXED(bp, IGU_REG_LEADING_EDGE_LATCH, val);
=20
 	/* Make sure that interrupts are indeed enabled from here on */
 	mmiowb();
@@ -3817,8 +3817,8 @@ static void bnx2x_sp_prod_update(struct bnx2x *bp)
 	 */
 	mb();
=20
-	REG_WR16(bp, BAR_XSTRORM_INTMEM + XSTORM_SPQ_PROD_OFFSET(func),
-		 bp->spq_prod_idx);
+	REG_WR16_RELAXED(bp, BAR_XSTRORM_INTMEM + XSTORM_SPQ_PROD_OFFSET(func),
+			 bp->spq_prod_idx);
 	mmiowb();
 }
=20
@@ -7761,7 +7761,7 @@ void bnx2x_igu_clear_sb_gen(struct bnx2x *bp, u8 func=
, u8 idu_sb_id, bool is_pf)
 	barrier();
 	DP(NETIF_MSG_HW, "write 0x%08x to IGU(via GRC) addr 0x%x\n",
 			  ctl, igu_addr_ctl);
-	REG_WR(bp, igu_addr_ctl, ctl);
+	REG_WR_RELAXED(bp, igu_addr_ctl, ctl);
 	mmiowb();
 	barrier();
=20
@@ -9720,13 +9720,14 @@ static void bnx2x_process_kill_chip_reset(struct bn=
x2x *bp, bool global)
 	barrier();
 	mmiowb();
=20
-	REG_WR(bp, GRCBASE_MISC + MISC_REGISTERS_RESET_REG_2_SET,
-	       reset_mask2 & (~stay_reset2));
+	REG_WR_RELAXED(bp, GRCBASE_MISC + MISC_REGISTERS_RESET_REG_2_SET,
+		       reset_mask2 & (~stay_reset2));
=20
 	barrier();
 	mmiowb();
=20
-	REG_WR(bp, GRCBASE_MISC + MISC_REGISTERS_RESET_REG_1_SET, reset_mask1);
+	REG_WR_RELAXED(bp, GRCBASE_MISC + MISC_REGISTERS_RESET_REG_1_SET,
+		       reset_mask1);
 	mmiowb();
 }
=20
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c b/drivers/ne=
t/ethernet/broadcom/bnx2x/bnx2x_sriov.c
index ffa7959..40e55d8 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_sriov.c
@@ -105,7 +105,7 @@ static void bnx2x_vf_igu_ack_sb(struct bnx2x *bp, struc=
t bnx2x_virtf *vf,
=20
 	DP(NETIF_MSG_HW, "write 0x%08x to IGU(via GRC) addr 0x%x\n",
 	   ctl, igu_addr_ctl);
-	REG_WR(bp, igu_addr_ctl, ctl);
+	REG_WR_RELAXED(bp, igu_addr_ctl, ctl);
 	mmiowb();
 	barrier();
 }
diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c b/drivers/net=
/ethernet/broadcom/bnx2x/bnx2x_vfpf.c
index 76a4668..3b2f1bd 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c
@@ -170,7 +170,7 @@ static int bnx2x_send_msg2pf(struct bnx2x *bp, u8 *done=
, dma_addr_t msg_mapping)
 	wmb();
=20
 	/* Trigger the PF FW */
-	writeb(1, &zone_data->trigger.vf_pf_channel.addr_valid);
+	writeb_relaxed(1, &zone_data->trigger.vf_pf_channel.addr_valid);
=20
 	/* Wait for PF to complete */
 	while ((tout >=3D 0) && (!*done)) {
--
2.7.4

Acked-by: Sudarsana Kalluru <Sudarsana.Kalluru@cavium.com>