linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Lijun Ou <oulijun@huawei.com>
To: <dledford@redhat.com>, <sean.hefty@intel.com>,
	<hal.rosenstock@gmail.com>, <davem@davemloft.net>,
	<jeffrey.t.kirsher@intel.com>, <jiri@mellanox.com>,
	<ogerlitz@mellanox.com>
Cc: <linux-rdma@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<netdev@vger.kernel.org>, <gongyangming@huawei.com>,
	<xiaokun@huawei.com>, <tangchaofei@huawei.com>,
	<oulijun@huawei.com>, <haifeng.wei@huawei.com>,
	<yisen.zhuang@huawei.com>, <yankejian@huawei.com>,
	<charles.chenxin@huawei.com>, <linuxarm@huawei.com>
Subject: [PATCH v10 12/22] IB/hns: Set mtu and gid support
Date: Thu, 16 Jun 2016 22:35:20 +0800	[thread overview]
Message-ID: <1466087730-54856-13-git-send-email-oulijun@huawei.com> (raw)
In-Reply-To: <1466087730-54856-1-git-send-email-oulijun@huawei.com>

This patch mainly set mtu and gid resource. These resource
will be used to set up network transmission in nodes.

Signed-off-by: Wei Hu <xavier.huwei@huawei.com>
Signed-off-by: Nenglong Zhao <zhaonenglong@hisilicon.com>
Signed-off-by: Lijun Ou <oulijun@huawei.com>
---
PATCH v9/v8/v7/v6:
- No change over the PATCH v5

PATCH v5:
- The initial patch which was redesigned based on the second patch
  in PATCH v4
---
---
 drivers/infiniband/hw/hns/hns_roce_common.h |  16 ++++
 drivers/infiniband/hw/hns/hns_roce_device.h |  14 ++++
 drivers/infiniband/hw/hns/hns_roce_hw_v1.c  |  68 ++++++++++++++-
 drivers/infiniband/hw/hns/hns_roce_hw_v1.h  |   7 +-
 drivers/infiniband/hw/hns/hns_roce_main.c   | 123 ++++++++++++++++++++++++++++
 5 files changed, 223 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_common.h b/drivers/infiniband/hw/hns/hns_roce_common.h
index 776286c..b66e96f 100644
--- a/drivers/infiniband/hw/hns/hns_roce_common.h
+++ b/drivers/infiniband/hw/hns/hns_roce_common.h
@@ -156,6 +156,14 @@
 
 #define ROCEE_BT_CMD_H_ROCEE_BT_CMD_HW_SYNS_S 31
 
+#define ROCEE_SMAC_H_ROCEE_SMAC_H_S 0
+#define ROCEE_SMAC_H_ROCEE_SMAC_H_M   \
+	(((1UL << 16) - 1) << ROCEE_SMAC_H_ROCEE_SMAC_H_S)
+
+#define ROCEE_SMAC_H_ROCEE_PORT_MTU_S 16
+#define ROCEE_SMAC_H_ROCEE_PORT_MTU_M   \
+	(((1UL << 4) - 1) << ROCEE_SMAC_H_ROCEE_PORT_MTU_S)
+
 #define ROCEE_CAEP_AEQC_AEQE_SHIFT_CAEP_AEQC_STATE_S 0
 #define ROCEE_CAEP_AEQC_AEQE_SHIFT_CAEP_AEQC_STATE_M   \
 	(((1UL << 2) - 1) << ROCEE_CAEP_AEQC_AEQE_SHIFT_CAEP_AEQC_STATE_S)
@@ -196,8 +204,16 @@
 #define ROCEE_SYS_IMAGE_GUID_L_REG		0xC
 #define ROCEE_SYS_IMAGE_GUID_H_REG		0x10
 
+#define ROCEE_PORT_GID_L_0_REG			0x50
+#define ROCEE_PORT_GID_ML_0_REG			0x54
+#define ROCEE_PORT_GID_MH_0_REG			0x58
+#define ROCEE_PORT_GID_H_0_REG			0x5C
+
 #define ROCEE_BT_CMD_H_REG			0x204
 
+#define ROCEE_SMAC_L_0_REG			0x240
+#define ROCEE_SMAC_H_0_REG			0x244
+
 #define ROCEE_CAEP_AEQE_CONS_IDX_REG		0x3AC
 #define ROCEE_CAEP_CEQC_CONS_IDX_0_REG		0x3BC
 
diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h b/drivers/infiniband/hw/hns/hns_roce_device.h
index 727e136..b7c1773 100644
--- a/drivers/infiniband/hw/hns/hns_roce_device.h
+++ b/drivers/infiniband/hw/hns/hns_roce_device.h
@@ -44,6 +44,8 @@
 
 #define DRV_NAME "hns_roce"
 
+#define MAC_ADDR_OCTET_NUM			6
+
 #define HNS_ROCE_BA_SIZE			(32 * 4096)
 
 #define HNS_ROCE_MAX_IRQ_NUM			34
@@ -54,6 +56,9 @@
 #define HNS_ROCE_AEQE_OF_VEC_NUM		1
 
 #define HNS_ROCE_MAX_PORTS			6
+#define HNS_ROCE_MAX_GID_NUM			16
+
+#define PAGES_SHIFT_16				16
 
 enum hns_roce_event {
 	HNS_ROCE_EVENT_TYPE_PATH_MIG                  = 0x01,
@@ -252,6 +257,8 @@ struct hns_roce_qp {
 
 struct hns_roce_ib_iboe {
 	struct net_device      *netdevs[HNS_ROCE_MAX_PORTS];
+	/* 16 GID is shared by 6 port in v1 engine. */
+	union ib_gid		gid_table[HNS_ROCE_MAX_GID_NUM];
 	u8			phy_port[HNS_ROCE_MAX_PORTS];
 };
 
@@ -325,6 +332,11 @@ struct hns_roce_hw {
 	void (*hw_profile)(struct hns_roce_dev *hr_dev);
 	int (*hw_init)(struct hns_roce_dev *hr_dev);
 	void (*hw_exit)(struct hns_roce_dev *hr_dev);
+	void (*set_gid)(struct hns_roce_dev *hr_dev, u8 port, int gid_index,
+			union ib_gid *gid);
+	void (*set_mac)(struct hns_roce_dev *hr_dev, u8 phy_port, u8 *addr);
+	void (*set_mtu)(struct hns_roce_dev *hr_dev, u8 phy_port,
+			enum ib_mtu mtu);
 	void	*priv;
 };
 
@@ -343,6 +355,7 @@ struct hns_roce_dev {
 	struct hns_roce_caps	caps;
 	struct radix_tree_root  qp_table_tree;
 
+	unsigned char	dev_addr[HNS_ROCE_MAX_PORTS][MAC_ADDR_OCTET_NUM];
 	u64                     fw_ver;
 	u64			sys_image_guid;
 	u32                     vendor_id;
@@ -412,6 +425,7 @@ void hns_roce_bitmap_free_range(struct hns_roce_bitmap *bitmap,
 void hns_roce_cq_completion(struct hns_roce_dev *hr_dev, u32 cqn);
 void hns_roce_cq_event(struct hns_roce_dev *hr_dev, u32 cqn, int event_type);
 void hns_roce_qp_event(struct hns_roce_dev *hr_dev, u32 qpn, int event_type);
+int hns_get_gid_index(struct hns_roce_dev *hr_dev, u8 port, int gid_index);
 
 extern struct hns_roce_hw hns_roce_hw_v1;
 
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
index d8069fb..7bdd7ab 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v1.c
@@ -39,8 +39,8 @@
 #include "hns_roce_device.h"
 #include "hns_roce_hw_v1.h"
 
-void hns_roce_set_db_event_mode(struct hns_roce_dev *hr_dev, int sdb_mode,
-				int odb_mode)
+static void hns_roce_set_db_event_mode(struct hns_roce_dev *hr_dev,
+				       int sdb_mode, int odb_mode)
 {
 	u32 val;
 
@@ -582,9 +582,73 @@ void hns_roce_v1_exit(struct hns_roce_dev *hr_dev)
 	hns_roce_db_free(hr_dev);
 }
 
+void hns_roce_v1_set_gid(struct hns_roce_dev *hr_dev, u8 port, int gid_index,
+			 union ib_gid *gid)
+{
+	u32 *p = NULL;
+	u8 gid_idx = 0;
+
+	gid_idx = hns_get_gid_index(hr_dev, port, gid_index);
+
+	p = (u32 *)&gid->raw[0];
+	roce_raw_write(*p, hr_dev->reg_base + ROCEE_PORT_GID_L_0_REG +
+		       (HNS_ROCE_V1_GID_NUM * gid_idx));
+
+	p = (u32 *)&gid->raw[4];
+	roce_raw_write(*p, hr_dev->reg_base + ROCEE_PORT_GID_ML_0_REG +
+		       (HNS_ROCE_V1_GID_NUM * gid_idx));
+
+	p = (u32 *)&gid->raw[8];
+	roce_raw_write(*p, hr_dev->reg_base + ROCEE_PORT_GID_MH_0_REG +
+		       (HNS_ROCE_V1_GID_NUM * gid_idx));
+
+	p = (u32 *)&gid->raw[0xc];
+	roce_raw_write(*p, hr_dev->reg_base + ROCEE_PORT_GID_H_0_REG +
+		       (HNS_ROCE_V1_GID_NUM * gid_idx));
+}
+
+void hns_roce_v1_set_mac(struct hns_roce_dev *hr_dev, u8 phy_port, u8 *addr)
+{
+	u32 reg_smac_l;
+	u16 reg_smac_h;
+	u16 *p_h;
+	u32 *p;
+	u32 val;
+
+	p = (u32 *)(&addr[0]);
+	reg_smac_l = *p;
+	roce_raw_write(reg_smac_l, hr_dev->reg_base + ROCEE_SMAC_L_0_REG +
+		       PHY_PORT_OFFSET * phy_port);
+
+	val = roce_read(hr_dev,
+			ROCEE_SMAC_H_0_REG + phy_port * PHY_PORT_OFFSET);
+	p_h = (u16 *)(&addr[4]);
+	reg_smac_h  = *p_h;
+	roce_set_field(val, ROCEE_SMAC_H_ROCEE_SMAC_H_M,
+		       ROCEE_SMAC_H_ROCEE_SMAC_H_S, reg_smac_h);
+	roce_write(hr_dev, ROCEE_SMAC_H_0_REG + phy_port * PHY_PORT_OFFSET,
+		   val);
+}
+
+void hns_roce_v1_set_mtu(struct hns_roce_dev *hr_dev, u8 phy_port,
+			 enum ib_mtu mtu)
+{
+	u32 val;
+
+	val = roce_read(hr_dev,
+			ROCEE_SMAC_H_0_REG + phy_port * PHY_PORT_OFFSET);
+	roce_set_field(val, ROCEE_SMAC_H_ROCEE_PORT_MTU_M,
+		       ROCEE_SMAC_H_ROCEE_PORT_MTU_S, mtu);
+	roce_write(hr_dev, ROCEE_SMAC_H_0_REG + phy_port * PHY_PORT_OFFSET,
+		   val);
+}
+
 struct hns_roce_hw hns_roce_hw_v1 = {
 	.reset = hns_roce_v1_reset,
 	.hw_profile = hns_roce_v1_profile,
 	.hw_init = hns_roce_v1_init,
 	.hw_exit = hns_roce_v1_exit,
+	.set_gid = hns_roce_v1_set_gid,
+	.set_mac = hns_roce_v1_set_mac,
+	.set_mtu = hns_roce_v1_set_mtu,
 };
diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v1.h b/drivers/infiniband/hw/hns/hns_roce_hw_v1.h
index b9486bb..e7592a1 100644
--- a/drivers/infiniband/hw/hns/hns_roce_hw_v1.h
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v1.h
@@ -107,9 +107,10 @@
 
 #define HNS_ROCE_ODB_EXTEND_MODE			1
 
-#define ALL_PORT_VAL_OPEN				0x3f
-#define POL_TIME_INTERVAL_VAL				0x80
-#define SLEEP_TIME_INTERVAL				20
+#define PHY_PORT_OFFSET				0x8
+#define ALL_PORT_VAL_OPEN			0x3f
+#define POL_TIME_INTERVAL_VAL			0x80
+#define SLEEP_TIME_INTERVAL			20
 
 struct hns_roce_ext_db {
 	int esdb_dep;
diff --git a/drivers/infiniband/hw/hns/hns_roce_main.c b/drivers/infiniband/hw/hns/hns_roce_main.c
index 24572ec..6c13f6d 100644
--- a/drivers/infiniband/hw/hns/hns_roce_main.c
+++ b/drivers/infiniband/hw/hns/hns_roce_main.c
@@ -61,6 +61,118 @@
 #include "hns_roce_device.h"
 #include "hns_roce_icm.h"
 
+/**
+ * hns_get_gid_index - Get gid index.
+ * @hr_dev: pointer to structure hns_roce_dev.
+ * @port:  port, value range: 0 ~ MAX
+ * @gid_index:  gid_index, value range: 0 ~ MAX
+ * Description:
+ *    N ports shared gids, allocation method as follow:
+ *		GID[0][0], GID[1][0],.....GID[N - 1][0],
+ *		GID[0][0], GID[1][0],.....GID[N - 1][0],
+ *		And so on
+ */
+int hns_get_gid_index(struct hns_roce_dev *hr_dev, u8 port, int gid_index)
+{
+	return gid_index * hr_dev->caps.num_ports + port;
+}
+
+static int hns_roce_set_gid(struct hns_roce_dev *hr_dev, u8 port, int gid_index,
+		     union ib_gid *gid)
+{
+	struct device *dev = &hr_dev->pdev->dev;
+	u8 gid_idx = 0;
+
+	if (gid_index >= hr_dev->caps.gid_table_len[port]) {
+		dev_err(dev, "gid_index %d illegal, port %d gid range: 0~%d\n",
+			gid_index, port, hr_dev->caps.gid_table_len[port] - 1);
+		return -EINVAL;
+	}
+
+	gid_idx = hns_get_gid_index(hr_dev, port, gid_index);
+
+	if (!memcmp(gid, &hr_dev->iboe.gid_table[gid_idx], sizeof(*gid)))
+		return -EINVAL;
+
+	memcpy(&hr_dev->iboe.gid_table[gid_idx], gid, sizeof(*gid));
+
+	hr_dev->hw->set_gid(hr_dev, port, gid_index, gid);
+
+	return 0;
+}
+
+static void hns_roce_set_mac(struct hns_roce_dev *hr_dev, u8 port, u8 *addr)
+{
+	u8 phy_port;
+	u32 i = 0;
+
+	if (!memcmp(hr_dev->dev_addr[port], addr, MAC_ADDR_OCTET_NUM))
+		return;
+
+	for (i = 0; i < MAC_ADDR_OCTET_NUM; i++)
+		hr_dev->dev_addr[port][i] = addr[i];
+
+	phy_port = hr_dev->iboe.phy_port[port];
+	hr_dev->hw->set_mac(hr_dev, phy_port, addr);
+}
+
+static void hns_roce_set_mtu(struct hns_roce_dev *hr_dev, u8 port, int mtu)
+{
+	u8 phy_port = hr_dev->iboe.phy_port[port];
+	enum ib_mtu tmp;
+
+	tmp = iboe_get_mtu(mtu);
+	if (!tmp)
+		tmp = IB_MTU_256;
+
+	hr_dev->hw->set_mtu(hr_dev, phy_port, tmp);
+}
+
+static void hns_roce_update_gids(struct hns_roce_dev *hr_dev, int port)
+{
+	struct ib_event event;
+
+	/* Refresh gid in ib_cache */
+	event.device = &hr_dev->ib_dev;
+	event.element.port_num = port + 1;
+	event.event = IB_EVENT_GID_CHANGE;
+	ib_dispatch_event(&event);
+}
+
+static int hns_roce_setup_mtu_gids(struct hns_roce_dev  *hr_dev)
+{
+	struct in_ifaddr *ifa_list = NULL;
+	union ib_gid gid = {{0} };
+	u32 ipaddr = 0;
+	int index = 0;
+	int ret = 0;
+	u8 i = 0;
+
+	for (i = 0; i < hr_dev->caps.num_ports; i++) {
+		hns_roce_set_mtu(hr_dev, i,
+				 ib_mtu_enum_to_int(hr_dev->caps.max_mtu));
+		hns_roce_set_mac(hr_dev, i, hr_dev->iboe.netdevs[i]->dev_addr);
+
+		if (hr_dev->iboe.netdevs[i]->ip_ptr) {
+			ifa_list = hr_dev->iboe.netdevs[i]->ip_ptr->ifa_list;
+			index = 1;
+			while (ifa_list) {
+				ipaddr = ifa_list->ifa_address;
+				ipv6_addr_set_v4mapped(ipaddr,
+						       (struct in6_addr *)&gid);
+				ret = hns_roce_set_gid(hr_dev, i, index, &gid);
+				if (ret)
+					break;
+				index++;
+				ifa_list = ifa_list->ifa_next;
+			}
+			hns_roce_update_gids(hr_dev, i);
+		}
+	}
+
+	return ret;
+}
+
 static void hns_roce_unregister_device(struct hns_roce_dev *hr_dev)
 {
 	ib_unregister_device(&hr_dev->ib_dev);
@@ -93,7 +205,18 @@ static int hns_roce_register_device(struct hns_roce_dev *hr_dev)
 		return ret;
 	}
 
+	ret = hns_roce_setup_mtu_gids(hr_dev);
+	if (ret) {
+		dev_err(dev, "roce_setup_mtu_gids failed!\n");
+		goto error_failed_setup_mtu_gids;
+	}
+
 	return 0;
+
+error_failed_setup_mtu_gids:
+	ib_unregister_device(ib_dev);
+
+	return ret;
 }
 
 static int hns_roce_get_cfg(struct hns_roce_dev *hr_dev)
-- 
1.9.1

  parent reply	other threads:[~2016-06-16 14:31 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-16 14:35 [PATCH v10 00/22] Add HiSilicon RoCE driver Lijun Ou
2016-06-16 14:35 ` [PATCH v10 01/22] net: hns: Add reset function support for " Lijun Ou
2016-06-24 11:49   ` Leon Romanovsky
2016-06-27  6:41     ` oulijun
2016-06-16 14:35 ` [PATCH v10 02/22] devicetree: bindings: IB: Add binding document for HiSilicon RoCE Lijun Ou
2016-06-16 14:35 ` [PATCH v10 03/22] IB/hns: Add initial main frame driver and get cfg info Lijun Ou
2016-06-24 11:48   ` Leon Romanovsky
     [not found]     ` <576E5D0B.7010003@huawei.com>
2016-06-27  7:00       ` Leon Romanovsky
2016-06-27  7:29         ` Wei Hu (Xavier)
2016-06-16 14:35 ` [PATCH v10 04/22] IB/hns: Add RoCE engine reset function Lijun Ou
2016-06-24 14:59   ` Leon Romanovsky
     [not found]     ` <576E5C21.5030904@huawei.com>
2016-06-27  8:01       ` Leon Romanovsky
2016-06-27  8:31         ` oulijun
2016-06-28  6:31           ` Wei Hu (Xavier)
2016-06-28  8:09             ` Leon Romanovsky
2016-06-16 14:35 ` [PATCH v10 05/22] IB/hns: Add initial profile resource Lijun Ou
2016-06-24 15:10   ` Leon Romanovsky
2016-06-28  6:56     ` oulijun
2016-06-16 14:35 ` [PATCH v10 06/22] IB/hns: Add initial cmd operation Lijun Ou
2016-06-20 13:33   ` Leon Romanovsky
2016-06-21 10:50     ` Wei Hu (Xavier)
2016-06-21 11:28       ` Leon Romanovsky
2016-06-21 13:01         ` Wei Hu (Xavier)
2016-06-22  4:54           ` Leon Romanovsky
2016-06-22  6:50             ` Wei Hu (Xavier)
2016-06-16 14:35 ` [PATCH v10 07/22] IB/hns: Add event queue support Lijun Ou
2016-06-24 15:46   ` Leon Romanovsky
2016-06-24 15:56     ` Doug Ledford
2016-06-29  8:53     ` oulijun
2016-06-29 10:41       ` Leon Romanovsky
2016-06-16 14:35 ` [PATCH v10 08/22] IB/hns: Add icm support Lijun Ou
2016-06-17  9:58   ` Leon Romanovsky
     [not found]     ` <57677314.70909@huawei.com>
2016-06-20  6:06       ` Leon Romanovsky
2016-06-20  7:49         ` Wei Hu (Xavier)
2016-06-20  9:27           ` Leon Romanovsky
2016-06-20  9:48             ` Wei Hu (Xavier)
2016-06-20 13:04               ` Leon Romanovsky
2016-06-21  4:37                 ` Wei Hu (Xavier)
2016-06-21 11:55                   ` Leon Romanovsky
2016-06-22  3:53                     ` Wei Hu (Xavier)
2016-06-16 14:35 ` [PATCH v10 09/22] IB/hns: Add hca support Lijun Ou
2016-06-24 15:50   ` Leon Romanovsky
2016-06-16 14:35 ` [PATCH v10 10/22] IB/hns: Add process flow to init RoCE engine Lijun Ou
2016-06-16 14:35 ` [PATCH v10 11/22] IB/hns: Add IB device registration Lijun Ou
2016-06-16 14:35 ` Lijun Ou [this message]
2016-06-16 14:35 ` [PATCH v10 13/22] IB/hns: Add interface of the protocol stack registration Lijun Ou
2016-06-16 14:35 ` [PATCH v10 14/22] IB/hns: Add operations support for IB device and port Lijun Ou
2016-06-16 14:35 ` [PATCH v10 15/22] IB/hns: Add PD operations support Lijun Ou
2016-06-16 14:35 ` [PATCH v10 16/22] IB/hns: Add ah " Lijun Ou
2016-06-16 14:35 ` [PATCH v10 17/22] IB/hns: Add QP " Lijun Ou
2016-06-16 14:35 ` [PATCH v10 18/22] IB/hns: Add CQ " Lijun Ou
2016-06-16 14:35 ` [PATCH v10 19/22] IB/hns: Add memory region " Lijun Ou
2016-06-16 14:35 ` [PATCH v10 20/22] IB/hns: Add operation for getting immutable port Lijun Ou
2016-06-16 14:35 ` [PATCH v10 21/22] IB/hns: Kconfig and Makefile for RoCE module Lijun Ou
2016-06-16 14:35 ` [PATCH v10 22/22] MAINTAINERS: Add maintainers for HiSilicon RoCE driver Lijun Ou
2016-06-24 15:55 ` [PATCH v10 00/22] Add " Leon Romanovsky

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1466087730-54856-13-git-send-email-oulijun@huawei.com \
    --to=oulijun@huawei.com \
    --cc=charles.chenxin@huawei.com \
    --cc=davem@davemloft.net \
    --cc=dledford@redhat.com \
    --cc=gongyangming@huawei.com \
    --cc=haifeng.wei@huawei.com \
    --cc=hal.rosenstock@gmail.com \
    --cc=jeffrey.t.kirsher@intel.com \
    --cc=jiri@mellanox.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=linuxarm@huawei.com \
    --cc=netdev@vger.kernel.org \
    --cc=ogerlitz@mellanox.com \
    --cc=sean.hefty@intel.com \
    --cc=tangchaofei@huawei.com \
    --cc=xiaokun@huawei.com \
    --cc=yankejian@huawei.com \
    --cc=yisen.zhuang@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).