New subject: [M] Change in coreboot[master]: ec: Add support for MEC5055 for Dell laptops

Sept. 1, 2020

Hello Iru Cai,

I'd like you to do a code review. Please visit

    https://review.coreboot.org/c/coreboot/+/44975

to review the following change.


Change subject: ec: Add support for MEC5055 for Dell laptops
......................................................................

ec: Add support for MEC5055 for Dell laptops

This EC support code is required to boot various Dell Latitude laptops,
otherwise the laptop will shut down in a minute after powered on.

Tested on Dell Latitude E7240.

Change-Id: Iee68ea52dcf0242315868a46b5e4768303e30dce
Signed-off-by: Iru Cai <mytbk920423@gmail.com>
---
A src/ec/dell/mec5055/Kconfig
A src/ec/dell/mec5055/Makefile.inc
A src/ec/dell/mec5055/early_init.c
A src/ec/dell/mec5055/mec5055.c
A src/ec/dell/mec5055/mec5055.h
5 files changed, 148 insertions(+), 0 deletions(-)



  git pull ssh://review.coreboot.org:29418/coreboot refs/changes/75/44975/1

diff --git a/src/ec/dell/mec5055/Kconfig b/src/ec/dell/mec5055/Kconfig
new file mode 100644
index 0000000..a7bf9a5
--- /dev/null
+++ b/src/ec/dell/mec5055/Kconfig
@@ -0,0 +1,4 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
+config EC_DELL_MEC5055
+	bool
diff --git a/src/ec/dell/mec5055/Makefile.inc b/src/ec/dell/mec5055/Makefile.inc
new file mode 100644
index 0000000..9cdfbb3
--- /dev/null
+++ b/src/ec/dell/mec5055/Makefile.inc
@@ -0,0 +1,8 @@
+## SPDX-License-Identifier: GPL-2.0-only
+
+ifeq ($(CONFIG_EC_DELL_MEC5055),y)
+
+bootblock-y += mec5055.c early_init.c
+romstage-y += mec5055.c early_init.c
+
+endif
diff --git a/src/ec/dell/mec5055/early_init.c b/src/ec/dell/mec5055/early_init.c
new file mode 100644
index 0000000..6aec48b
--- /dev/null
+++ b/src/ec/dell/mec5055/early_init.c
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
+
+#include "mec5055.h"
+
+void mec5055_early_init(void)
+{
+	u8 buf[32], c;
+
+	mec5055_ec_command_0(buf, 0xc2, 0);
+	mec5055_ec_command_1(0xab, NULL, 0, &c, 1);
+}
diff --git a/src/ec/dell/mec5055/mec5055.c b/src/ec/dell/mec5055/mec5055.c
new file mode 100644
index 0000000..2deec7d
--- /dev/null
+++ b/src/ec/dell/mec5055/mec5055.c
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
+
+#include <arch/io.h>
+#include "mec5055.h"
+
+static const u16 EC_CTRL = 0x910;
+static const u16 EC_DATA = 0x911;
+
+static void wait_ec(void)
+{
+	u8 v;
+	do {
+		outb(0, EC_CTRL);
+		v = inb(EC_DATA);
+	} while (v != 0);
+}
+
+static int read_ec_regs(u8 start, u8 *sdata, u8 count)
+{
+	if (start >= 0x20 || start + count > 0x20)
+		return -1;
+
+	if (count <= 0)
+		return 0;
+
+	while (count--) {
+		outb(start + 0x10, EC_CTRL);
+		*sdata = inb(EC_DATA);
+		sdata++;
+		start++;
+	}
+
+	return 0;
+}
+
+static int write_ec_regs(u8 start, const u8 *sdata, u8 count)
+{
+	if (start >= 0x20 || start + count > 0x20)
+		return -1;
+
+	if (count <= 0)
+		return 0;
+
+	while (count--) {
+		outb(start + 0x10, EC_CTRL);
+		outb(*sdata, EC_DATA);
+		sdata++;
+		start++;
+	}
+
+	return 0;
+}
+
+/* Steps to communicate with the EC:
+ * 1. send command:
+ *   - write arguments to EC[2:]
+ *   - send 0 to CTRL then cmd to DATA
+ * 2. wait EC
+ * 3. receive result: result may starts at EC[0] or EC[1]
+ */
+
+/* send command to EC and wait, command at cmd[0], args in cmd[2:] */
+static int ec_send_command(const u8 *cmd, int argc)
+{
+	int result = 0;
+
+	if (argc > 0) {
+		if (argc > 0x1e)
+			result = -1;
+		else
+			result = write_ec_regs(2, cmd + 2, argc);
+	}
+
+	outb(0, EC_CTRL);
+	outb(cmd[0], EC_DATA);
+	wait_ec();
+	return result;
+}
+
+/* receive result from EC[0:] */
+int mec5055_ec_command_0(u8 *buf, u8 cmd, int argc)
+{
+	buf[0] = cmd;
+	int res = ec_send_command(buf, argc);
+	if (res < 0)
+		return res;
+
+	return read_ec_regs(0, buf, 0x10);
+}
+
+/* receive result from EC[1:] */
+int mec5055_ec_command_1(u8 cmd, const u8 *cmd_buf, int argc, u8 *res_buf, int res_size)
+{
+	if (argc >= 0x1e)
+		argc = 0x1e;
+
+	if (res_size >= 0x1f)
+		res_size = 0x1f;
+
+	int t = write_ec_regs(2, cmd_buf, argc);
+	if (t < 0)
+		return t;
+
+	outb(0, EC_CTRL);
+	outb(cmd, EC_DATA);
+	wait_ec();
+
+	return read_ec_regs(1, res_buf, res_size);
+}
diff --git a/src/ec/dell/mec5055/mec5055.h b/src/ec/dell/mec5055/mec5055.h
new file mode 100644
index 0000000..33c6a1d
--- /dev/null
+++ b/src/ec/dell/mec5055/mec5055.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* This file is part of the coreboot project. */
+
+#ifndef _EC_DELL_MEC5055_H_
+#define _EC_DELL_MEC5055_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+int mec5055_ec_command_0(u8 *buf, u8 cmd, int argc);
+int mec5055_ec_command_1(u8 cmd, const u8 *cmd_buf, int argc, u8 *res_buf, int res_size);
+void mec5055_early_init(void);
+
+#endif

-- 
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Gerrit-Project: coreboot
Gerrit-Branch: master
Gerrit-Change-Id: Iee68ea52dcf0242315868a46b5e4768303e30dce
Gerrit-Change-Number: 44975
Gerrit-PatchSet: 1
Gerrit-Owner: Iru Cai (vimacs) <mytbk920423@gmail.com>
Gerrit-Reviewer: Iru Cai <mytbk920423@gmail.com>
Gerrit-Reviewer: Martin Roth <martinroth@google.com>
Gerrit-Reviewer: Patrick Georgi <pgeorgi@google.com>
Gerrit-MessageType: newchange

    

Change in coreboot[master]: ec: Add support for MEC5055 for Dell laptops

Iru Cai (vimacs) (Code Review)

HAOUAS Elyes (Code Review)

Paul Menzel (Code Review)

Iru Cai (vimacs) (Code Review)

Michał Żygowski (Code Review)

Iru Cai (vimacs) (Code Review)

Iru Cai (vimacs) (Code Review)

Arthur Heymans (Code Review)

Angel Pons (Code Review)

Paul Menzel (Code Review)

Martin L Roth (Code Review)

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