public inbox for linux-sunxi@lists.linux.dev
 help / color / mirror / Atom feed
From: Samuel Holland <samuel@sholland.org>
To: Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	linux-sunxi@lists.linux.dev
Cc: Michael Turquette <mturquette@baylibre.com>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Stephen Boyd <sboyd@kernel.org>,
	linux-kernel@vger.kernel.org,
	Samuel Holland <samuel@sholland.org>
Subject: [PATCH v3 2/4] clk: sunxi-ng: Allow drivers to be built as modules
Date: Thu, 18 Nov 2021 21:33:35 -0600	[thread overview]
Message-ID: <20211119033338.25486-3-samuel@sholland.org> (raw)
In-Reply-To: <20211119033338.25486-1-samuel@sholland.org>

While it is useful to build all of the CCU drivers at once, only 1-3 of
them will be loaded at a time, or possibly none of them if the kernel is
booted on a non-sunxi platform. These CCU drivers are relatively large;
32-bit drivers have 30-50k of data each, while the 64-bit ones are
50-75k due to the increased pointer overhead. About half of that data
comes from relocations. Let's allow the user to build these drivers as
modules so only the necessary data is loaded.

As a first step, convert the CCUs that are already platform drivers.

When the drivers are built as modules, normally the file name becomes
the module name. However, the current file names are inconsistent with
the <platform>-<peripheral> name used everywhere else: the devicetree
bindings, the platform driver names, and the Kconfig symbols. Use
Makfile logic to rename the modules so they follow the usual pattern.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

(no changes since v1)

 drivers/clk/sunxi-ng/Kconfig             | 16 +++---
 drivers/clk/sunxi-ng/Makefile            | 64 ++++++++++++++++--------
 drivers/clk/sunxi-ng/ccu-sun50i-a100-r.c |  4 +-
 drivers/clk/sunxi-ng/ccu-sun50i-a100.c   |  4 +-
 drivers/clk/sunxi-ng/ccu-sun50i-a64.c    |  7 ++-
 drivers/clk/sunxi-ng/ccu-sun50i-h6.c     |  7 ++-
 drivers/clk/sunxi-ng/ccu-sun8i-a83t.c    |  7 ++-
 drivers/clk/sunxi-ng/ccu-sun8i-de2.c     |  9 ++--
 drivers/clk/sunxi-ng/ccu-sun8i-r40.c     |  6 ++-
 drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c  |  7 ++-
 drivers/clk/sunxi-ng/ccu-sun9i-a80-usb.c |  7 ++-
 drivers/clk/sunxi-ng/ccu-sun9i-a80.c     |  7 ++-
 12 files changed, 98 insertions(+), 47 deletions(-)

diff --git a/drivers/clk/sunxi-ng/Kconfig b/drivers/clk/sunxi-ng/Kconfig
index e76e1676f0f0..c004ffc10ef7 100644
--- a/drivers/clk/sunxi-ng/Kconfig
+++ b/drivers/clk/sunxi-ng/Kconfig
@@ -13,22 +13,22 @@ config SUNIV_F1C100S_CCU
 	depends on MACH_SUNIV || COMPILE_TEST
 
 config SUN50I_A64_CCU
-	bool "Support for the Allwinner A64 CCU"
+	tristate "Support for the Allwinner A64 CCU"
 	default ARM64 && ARCH_SUNXI
 	depends on (ARM64 && ARCH_SUNXI) || COMPILE_TEST
 
 config SUN50I_A100_CCU
-	bool "Support for the Allwinner A100 CCU"
+	tristate "Support for the Allwinner A100 CCU"
 	default ARM64 && ARCH_SUNXI
 	depends on (ARM64 && ARCH_SUNXI) || COMPILE_TEST
 
 config SUN50I_A100_R_CCU
-	bool "Support for the Allwinner A100 PRCM CCU"
+	tristate "Support for the Allwinner A100 PRCM CCU"
 	default ARM64 && ARCH_SUNXI
 	depends on (ARM64 && ARCH_SUNXI) || COMPILE_TEST
 
 config SUN50I_H6_CCU
-	bool "Support for the Allwinner H6 CCU"
+	tristate "Support for the Allwinner H6 CCU"
 	default ARM64 && ARCH_SUNXI
 	depends on (ARM64 && ARCH_SUNXI) || COMPILE_TEST
 
@@ -69,7 +69,7 @@ config SUN8I_A33_CCU
 	depends on MACH_SUN8I || COMPILE_TEST
 
 config SUN8I_A83T_CCU
-	bool "Support for the Allwinner A83T CCU"
+	tristate "Support for the Allwinner A83T CCU"
 	default MACH_SUN8I
 	depends on MACH_SUN8I || COMPILE_TEST
 
@@ -84,16 +84,16 @@ config SUN8I_V3S_CCU
 	depends on MACH_SUN8I || COMPILE_TEST
 
 config SUN8I_DE2_CCU
-	bool "Support for the Allwinner SoCs DE2 CCU"
+	tristate "Support for the Allwinner SoCs DE2 CCU"
 	default MACH_SUN8I || (ARM64 && ARCH_SUNXI)
 
 config SUN8I_R40_CCU
-	bool "Support for the Allwinner R40 CCU"
+	tristate "Support for the Allwinner R40 CCU"
 	default MACH_SUN8I
 	depends on MACH_SUN8I || COMPILE_TEST
 
 config SUN9I_A80_CCU
-	bool "Support for the Allwinner A80 CCU"
+	tristate "Support for the Allwinner A80 CCU"
 	default MACH_SUN9I
 	depends on MACH_SUN9I || COMPILE_TEST
 
diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index 96c324306d97..1020ed49a588 100644
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -21,24 +21,46 @@ obj-y				+= ccu_nm.o
 obj-y				+= ccu_mp.o
 
 # SoC support
-obj-$(CONFIG_SUNIV_F1C100S_CCU)	+= ccu-suniv-f1c100s.o
-obj-$(CONFIG_SUN50I_A64_CCU)	+= ccu-sun50i-a64.o
-obj-$(CONFIG_SUN50I_A100_CCU)	+= ccu-sun50i-a100.o
-obj-$(CONFIG_SUN50I_A100_R_CCU)	+= ccu-sun50i-a100-r.o
-obj-$(CONFIG_SUN50I_H6_CCU)	+= ccu-sun50i-h6.o
-obj-$(CONFIG_SUN50I_H616_CCU)	+= ccu-sun50i-h616.o
-obj-$(CONFIG_SUN50I_H6_R_CCU)	+= ccu-sun50i-h6-r.o
-obj-$(CONFIG_SUN4I_A10_CCU)	+= ccu-sun4i-a10.o
-obj-$(CONFIG_SUN5I_CCU)		+= ccu-sun5i.o
-obj-$(CONFIG_SUN6I_A31_CCU)	+= ccu-sun6i-a31.o
-obj-$(CONFIG_SUN8I_A23_CCU)	+= ccu-sun8i-a23.o
-obj-$(CONFIG_SUN8I_A33_CCU)	+= ccu-sun8i-a33.o
-obj-$(CONFIG_SUN8I_A83T_CCU)	+= ccu-sun8i-a83t.o
-obj-$(CONFIG_SUN8I_H3_CCU)	+= ccu-sun8i-h3.o
-obj-$(CONFIG_SUN8I_V3S_CCU)	+= ccu-sun8i-v3s.o
-obj-$(CONFIG_SUN8I_DE2_CCU)	+= ccu-sun8i-de2.o
-obj-$(CONFIG_SUN8I_R_CCU)	+= ccu-sun8i-r.o
-obj-$(CONFIG_SUN8I_R40_CCU)	+= ccu-sun8i-r40.o
-obj-$(CONFIG_SUN9I_A80_CCU)	+= ccu-sun9i-a80.o
-obj-$(CONFIG_SUN9I_A80_CCU)	+= ccu-sun9i-a80-de.o
-obj-$(CONFIG_SUN9I_A80_CCU)	+= ccu-sun9i-a80-usb.o
+obj-$(CONFIG_SUNIV_F1C100S_CCU)	+= suniv-f1c100s-ccu.o
+obj-$(CONFIG_SUN50I_A64_CCU)	+= sun50i-a64-ccu.o
+obj-$(CONFIG_SUN50I_A100_CCU)	+= sun50i-a100-ccu.o
+obj-$(CONFIG_SUN50I_A100_R_CCU)	+= sun50i-a100-r-ccu.o
+obj-$(CONFIG_SUN50I_H6_CCU)	+= sun50i-h6-ccu.o
+obj-$(CONFIG_SUN50I_H6_R_CCU)	+= sun50i-h6-r-ccu.o
+obj-$(CONFIG_SUN50I_H616_CCU)	+= sun50i-h616-ccu.o
+obj-$(CONFIG_SUN4I_A10_CCU)	+= sun4i-a10-ccu.o
+obj-$(CONFIG_SUN5I_CCU)		+= sun5i-ccu.o
+obj-$(CONFIG_SUN6I_A31_CCU)	+= sun6i-a31-ccu.o
+obj-$(CONFIG_SUN8I_A23_CCU)	+= sun8i-a23-ccu.o
+obj-$(CONFIG_SUN8I_A33_CCU)	+= sun8i-a33-ccu.o
+obj-$(CONFIG_SUN8I_A83T_CCU)	+= sun8i-a83t-ccu.o
+obj-$(CONFIG_SUN8I_H3_CCU)	+= sun8i-h3-ccu.o
+obj-$(CONFIG_SUN8I_R40_CCU)	+= sun8i-r40-ccu.o
+obj-$(CONFIG_SUN8I_V3S_CCU)	+= sun8i-v3s-ccu.o
+obj-$(CONFIG_SUN8I_DE2_CCU)	+= sun8i-de2-ccu.o
+obj-$(CONFIG_SUN8I_R_CCU)	+= sun8i-r-ccu.o
+obj-$(CONFIG_SUN9I_A80_CCU)	+= sun9i-a80-ccu.o
+obj-$(CONFIG_SUN9I_A80_CCU)	+= sun9i-a80-de-ccu.o
+obj-$(CONFIG_SUN9I_A80_CCU)	+= sun9i-a80-usb-ccu.o
+
+suniv-f1c100s-ccu-y		+= ccu-suniv-f1c100s.o
+sun50i-a64-ccu-y		+= ccu-sun50i-a64.o
+sun50i-a100-ccu-y		+= ccu-sun50i-a100.o
+sun50i-a100-r-ccu-y		+= ccu-sun50i-a100-r.o
+sun50i-h6-ccu-y			+= ccu-sun50i-h6.o
+sun50i-h6-r-ccu-y		+= ccu-sun50i-h6-r.o
+sun50i-h616-ccu-y		+= ccu-sun50i-h616.o
+sun4i-a10-ccu-y			+= ccu-sun4i-a10.o
+sun5i-ccu-y			+= ccu-sun5i.o
+sun6i-a31-ccu-y			+= ccu-sun6i-a31.o
+sun8i-a23-ccu-y			+= ccu-sun8i-a23.o
+sun8i-a33-ccu-y			+= ccu-sun8i-a33.o
+sun8i-a83t-ccu-y		+= ccu-sun8i-a83t.o
+sun8i-h3-ccu-y			+= ccu-sun8i-h3.o
+sun8i-r40-ccu-y			+= ccu-sun8i-r40.o
+sun8i-v3s-ccu-y			+= ccu-sun8i-v3s.o
+sun8i-de2-ccu-y			+= ccu-sun8i-de2.o
+sun8i-r-ccu-y			+= ccu-sun8i-r.o
+sun9i-a80-ccu-y			+= ccu-sun9i-a80.o
+sun9i-a80-de-ccu-y		+= ccu-sun9i-a80-de.o
+sun9i-a80-usb-ccu-y		+= ccu-sun9i-a80-usb.o
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a100-r.c b/drivers/clk/sunxi-ng/ccu-sun50i-a100-r.c
index 804729e0a208..fddd6c877cec 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a100-r.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a100-r.c
@@ -5,7 +5,6 @@
 
 #include <linux/clk-provider.h>
 #include <linux/module.h>
-#include <linux/of_address.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -213,3 +212,6 @@ static struct platform_driver sun50i_a100_r_ccu_driver = {
 	},
 };
 module_platform_driver(sun50i_a100_r_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a100.c b/drivers/clk/sunxi-ng/ccu-sun50i-a100.c
index 1d475d5a3d91..5f93b5526e13 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a100.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a100.c
@@ -6,7 +6,6 @@
 #include <linux/clk-provider.h>
 #include <linux/io.h>
 #include <linux/module.h>
-#include <linux/of_address.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -1275,3 +1274,6 @@ static struct platform_driver sun50i_a100_ccu_driver = {
 	},
 };
 module_platform_driver(sun50i_a100_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
index a8c5a92b7d0c..41519185600a 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
@@ -5,7 +5,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/io.h>
-#include <linux/of_address.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -980,4 +980,7 @@ static struct platform_driver sun50i_a64_ccu_driver = {
 		.of_match_table	= sun50i_a64_ccu_ids,
 	},
 };
-builtin_platform_driver(sun50i_a64_ccu_driver);
+module_platform_driver(sun50i_a64_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-h6.c b/drivers/clk/sunxi-ng/ccu-sun50i-h6.c
index e5672c10d065..1a5e418923f6 100644
--- a/drivers/clk/sunxi-ng/ccu-sun50i-h6.c
+++ b/drivers/clk/sunxi-ng/ccu-sun50i-h6.c
@@ -5,7 +5,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/io.h>
-#include <linux/of_address.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -1254,4 +1254,7 @@ static struct platform_driver sun50i_h6_ccu_driver = {
 		.of_match_table	= sun50i_h6_ccu_ids,
 	},
 };
-builtin_platform_driver(sun50i_h6_ccu_driver);
+module_platform_driver(sun50i_h6_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
index 3c310aea8cfa..76cbd9e9e89f 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
@@ -5,7 +5,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/io.h>
-#include <linux/of_address.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -920,4 +920,7 @@ static struct platform_driver sun8i_a83t_ccu_driver = {
 		.of_match_table	= sun8i_a83t_ccu_ids,
 	},
 };
-builtin_platform_driver(sun8i_a83t_ccu_driver);
+module_platform_driver(sun8i_a83t_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-de2.c b/drivers/clk/sunxi-ng/ccu-sun8i-de2.c
index 573b5051d305..e7e3ddf4a227 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-de2.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-de2.c
@@ -5,8 +5,8 @@
 
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
-#include <linux/of_address.h>
-#include <linux/of_platform.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 
@@ -394,4 +394,7 @@ static struct platform_driver sunxi_de2_clk_driver = {
 		.of_match_table	= sunxi_de2_clk_ids,
 	},
 };
-builtin_platform_driver(sunxi_de2_clk_driver);
+module_platform_driver(sunxi_de2_clk_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-r40.c b/drivers/clk/sunxi-ng/ccu-sun8i-r40.c
index 8bb18d9add05..31eca0d3bc1e 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-r40.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-r40.c
@@ -5,6 +5,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/io.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
 
@@ -1371,4 +1372,7 @@ static struct platform_driver sun8i_r40_ccu_driver = {
 		.of_match_table	= sun8i_r40_ccu_ids,
 	},
 };
-builtin_platform_driver(sun8i_r40_ccu_driver);
+module_platform_driver(sun8i_r40_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c b/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c
index 3cde2610f467..f2fe0e1cc3c0 100644
--- a/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c
+++ b/drivers/clk/sunxi-ng/ccu-sun9i-a80-de.c
@@ -5,7 +5,7 @@
 
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
-#include <linux/of_address.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/reset.h>
 
@@ -270,4 +270,7 @@ static struct platform_driver sun9i_a80_de_clk_driver = {
 		.of_match_table	= sun9i_a80_de_clk_ids,
 	},
 };
-builtin_platform_driver(sun9i_a80_de_clk_driver);
+module_platform_driver(sun9i_a80_de_clk_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun9i-a80-usb.c b/drivers/clk/sunxi-ng/ccu-sun9i-a80-usb.c
index 0740e8978ae8..575ae4ccc65f 100644
--- a/drivers/clk/sunxi-ng/ccu-sun9i-a80-usb.c
+++ b/drivers/clk/sunxi-ng/ccu-sun9i-a80-usb.c
@@ -5,7 +5,7 @@
 
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
-#include <linux/of_address.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -138,4 +138,7 @@ static struct platform_driver sun9i_a80_usb_clk_driver = {
 		.of_match_table	= sun9i_a80_usb_clk_ids,
 	},
 };
-builtin_platform_driver(sun9i_a80_usb_clk_driver);
+module_platform_driver(sun9i_a80_usb_clk_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
diff --git a/drivers/clk/sunxi-ng/ccu-sun9i-a80.c b/drivers/clk/sunxi-ng/ccu-sun9i-a80.c
index d416af29e0d3..730fd8e28014 100644
--- a/drivers/clk/sunxi-ng/ccu-sun9i-a80.c
+++ b/drivers/clk/sunxi-ng/ccu-sun9i-a80.c
@@ -5,7 +5,7 @@
 
 #include <linux/clk-provider.h>
 #include <linux/io.h>
-#include <linux/of_address.h>
+#include <linux/module.h>
 #include <linux/platform_device.h>
 
 #include "ccu_common.h"
@@ -1245,4 +1245,7 @@ static struct platform_driver sun9i_a80_ccu_driver = {
 		.of_match_table	= sun9i_a80_ccu_ids,
 	},
 };
-builtin_platform_driver(sun9i_a80_ccu_driver);
+module_platform_driver(sun9i_a80_ccu_driver);
+
+MODULE_IMPORT_NS(SUNXI_CCU);
+MODULE_LICENSE("GPL");
-- 
2.32.0


  parent reply	other threads:[~2021-11-19  3:33 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-19  3:33 [PATCH v3 0/4] clk: sunxi-ng: Module support Samuel Holland
2021-11-19  3:33 ` [PATCH v3 1/4] clk: sunxi-ng: Export symbols used by CCU drivers Samuel Holland
2021-11-19  3:33 ` Samuel Holland [this message]
2021-11-19  3:33 ` [PATCH v3 3/4] clk: sunxi-ng: Convert early providers to platform drivers Samuel Holland
2023-06-26 12:21   ` Måns Rullgård
2023-06-28  7:44     ` Maxime Ripard
2023-06-28 11:07       ` Måns Rullgård
2023-06-28 11:41         ` Maxime Ripard
2023-06-28 18:33           ` Måns Rullgård
2023-06-30 14:17             ` Maxime Ripard
2023-06-30 17:03               ` Måns Rullgård
2021-11-19  3:33 ` [PATCH v3 4/4] clk: sunxi-ng: Allow the CCU core to be built as a module Samuel Holland
2021-11-22  9:06 ` [PATCH v3 0/4] clk: sunxi-ng: Module support Maxime Ripard

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=20211119033338.25486-3-samuel@sholland.org \
    --to=samuel@sholland.org \
    --cc=jernej.skrabec@gmail.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-clk@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-sunxi@lists.linux.dev \
    --cc=mripard@kernel.org \
    --cc=mturquette@baylibre.com \
    --cc=sboyd@kernel.org \
    --cc=wens@csie.org \
    /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