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Subject[PATCH 06/13] platform/chrome: cros_ec_lpc: Add support for mec1322 EC
Date
From: Shawn Nematbakhsh <shawnn@chromium.org>

This adds support for the ChromeOS LPC Microchip Embedded Controller
(mec1322) variant.

mec1322 accesses I/O region [800h, 9ffh] through embedded memory
interface (EMI) rather than LPC.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
---
Changelog:
- v2:
-Add a few lines in Kconfig description
-Fixed coding style issues
-Updated copyright to year 2016

drivers/platform/chrome/Kconfig | 12 +++
drivers/platform/chrome/Makefile | 1 +
drivers/platform/chrome/cros_ec_lpc.c | 5 ++
drivers/platform/chrome/cros_ec_lpc_mec.c | 140 ++++++++++++++++++++++++++++++
drivers/platform/chrome/cros_ec_lpc_reg.c | 69 +++++++++++++++
include/linux/mfd/cros_ec_lpc_mec.h | 90 +++++++++++++++++++
include/linux/mfd/cros_ec_lpc_reg.h | 14 +++
7 files changed, 331 insertions(+)
create mode 100644 drivers/platform/chrome/cros_ec_lpc_mec.c
create mode 100644 include/linux/mfd/cros_ec_lpc_mec.h

diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
index 76bdae1..6d80fb5 100644
--- a/drivers/platform/chrome/Kconfig
+++ b/drivers/platform/chrome/Kconfig
@@ -59,6 +59,18 @@ config CROS_EC_LPC
To compile this driver as a module, choose M here: the
module will be called cros_ec_lpc.

+config CROS_EC_LPC_MEC
+ bool "ChromeOS Embedded Controller LPC Microchip EC (MEC) variant"
+ depends on CROS_EC_LPC
+ default n
+ help
+ If you say Y here, a variant LPC protocol for the Microchip EC
+ will be used. Note that this variant is not backward compatible
+ with non-Microchip ECs.
+
+ If you have a ChromeOS Embedded Controller Microchip EC variant
+ choose Y here.
+
config CROS_EC_PROTO
bool
help
diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
index 61182fd..66c345c 100644
--- a/drivers/platform/chrome/Makefile
+++ b/drivers/platform/chrome/Makefile
@@ -6,6 +6,7 @@ cros_ec_devs-objs := cros_ec_dev.o cros_ec_sysfs.o \
cros_ec_debugfs.o
obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_devs.o
cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_reg.o
+cros_ec_lpcs-$(CONFIG_CROS_EC_LPC_MEC) += cros_ec_lpc_mec.o
obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o
obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
diff --git a/drivers/platform/chrome/cros_ec_lpc.c b/drivers/platform/chrome/cros_ec_lpc.c
index 6a782a6..bc2dc62 100644
--- a/drivers/platform/chrome/cros_ec_lpc.c
+++ b/drivers/platform/chrome/cros_ec_lpc.c
@@ -346,10 +346,13 @@ static int __init cros_ec_lpc_init(void)
return -ENODEV;
}

+ cros_ec_lpc_reg_init();
+
/* Register the driver */
ret = platform_driver_register(&cros_ec_lpc_driver);
if (ret) {
pr_err(DRV_NAME ": can't register driver: %d\n", ret);
+ cros_ec_lpc_reg_destroy();
return ret;
}

@@ -358,6 +361,7 @@ static int __init cros_ec_lpc_init(void)
if (ret) {
pr_err(DRV_NAME ": can't register device: %d\n", ret);
platform_driver_unregister(&cros_ec_lpc_driver);
+ cros_ec_lpc_reg_destroy();
return ret;
}

@@ -368,6 +372,7 @@ static void __exit cros_ec_lpc_exit(void)
{
platform_device_unregister(&cros_ec_lpc_device);
platform_driver_unregister(&cros_ec_lpc_driver);
+ cros_ec_lpc_reg_destroy();
}

module_init(cros_ec_lpc_init);
diff --git a/drivers/platform/chrome/cros_ec_lpc_mec.c b/drivers/platform/chrome/cros_ec_lpc_mec.c
new file mode 100644
index 0000000..2eda2c2
--- /dev/null
+++ b/drivers/platform/chrome/cros_ec_lpc_mec.c
@@ -0,0 +1,140 @@
+/*
+ * cros_ec_lpc_mec - LPC variant I/O for Microchip EC
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * This driver uses the Chrome OS EC byte-level message-based protocol for
+ * communicating the keyboard state (which keys are pressed) from a keyboard EC
+ * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
+ * but everything else (including deghosting) is done here. The main
+ * motivation for this is to keep the EC firmware as simple as possible, since
+ * it cannot be easily upgraded and EC flash/IRAM space is relatively
+ * expensive.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/mfd/cros_ec_lpc_mec.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+/*
+ * This mutex must be held while accessing the EMI unit. We can't rely on the
+ * EC mutex because memmap data may be accessed without it being held.
+ */
+static struct mutex io_mutex;
+
+/*
+ * cros_ec_lpc_mec_emi_write_address
+ *
+ * Initialize EMI read / write at a given address.
+ *
+ * @addr: Starting read / write address
+ * @access_type: Type of access, typically 32-bit auto-increment
+ */
+static void cros_ec_lpc_mec_emi_write_address(u16 addr,
+ enum cros_ec_lpc_mec_emi_access_mode access_type)
+{
+ /* Address relative to start of EMI range */
+ addr -= MEC_EMI_RANGE_START;
+ outb((addr & 0xfc) | access_type, MEC_EMI_EC_ADDRESS_B0);
+ outb((addr >> 8) & 0x7f, MEC_EMI_EC_ADDRESS_B1);
+}
+
+/*
+ * cros_ec_lpc_io_bytes_mec - Read / write bytes to MEC EMI port
+ *
+ * @io_type: MEC_IO_READ or MEC_IO_WRITE, depending on request
+ * @offset: Base read / write address
+ * @length: Number of bytes to read / write
+ * @buf: Destination / source buffer
+ *
+ * @return 8-bit checksum of all bytes read / written
+ */
+u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
+ unsigned int offset, unsigned int length,
+ u8 *buf)
+{
+ int i = 0;
+ int io_addr;
+ u8 sum = 0;
+ enum cros_ec_lpc_mec_emi_access_mode access, new_access;
+
+ /*
+ * Long access cannot be used on misaligned data since reading B0 loads
+ * the data register and writing B3 flushes.
+ */
+ if (offset & 0x3 || length < 4)
+ access = ACCESS_TYPE_BYTE;
+ else
+ access = ACCESS_TYPE_LONG_AUTO_INCREMENT;
+
+ mutex_lock(&io_mutex);
+
+ /* Initialize I/O at desired address */
+ cros_ec_lpc_mec_emi_write_address(offset, access);
+
+ /* Skip bytes in case of misaligned offset */
+ io_addr = MEC_EMI_EC_DATA_B0 + (offset & 0x3);
+ while (i < length) {
+ while (io_addr <= MEC_EMI_EC_DATA_B3) {
+ if (io_type == MEC_IO_READ)
+ buf[i] = inb(io_addr++);
+ else
+ outb(buf[i], io_addr++);
+
+ sum += buf[i++];
+ offset++;
+
+ /* Extra bounds check in case of misaligned length */
+ if (i == length)
+ goto done;
+ }
+
+ /*
+ * Use long auto-increment access except for misaligned write,
+ * since writing B3 triggers the flush.
+ */
+ if (length - i < 4 && io_type == MEC_IO_WRITE)
+ new_access = ACCESS_TYPE_BYTE;
+ else
+ new_access = ACCESS_TYPE_LONG_AUTO_INCREMENT;
+
+ if (new_access != access ||
+ access != ACCESS_TYPE_LONG_AUTO_INCREMENT) {
+ access = new_access;
+ cros_ec_lpc_mec_emi_write_address(offset, access);
+ }
+
+ /* Access [B0, B3] on each loop pass */
+ io_addr = MEC_EMI_EC_DATA_B0;
+ }
+
+done:
+ mutex_unlock(&io_mutex);
+
+ return sum;
+}
+EXPORT_SYMBOL(cros_ec_lpc_io_bytes_mec);
+
+void cros_ec_lpc_mec_init(void)
+{
+ mutex_init(&io_mutex);
+}
+EXPORT_SYMBOL(cros_ec_lpc_mec_init);
+
+void cros_ec_lpc_mec_destroy(void)
+{
+ mutex_destroy(&io_mutex);
+}
+EXPORT_SYMBOL(cros_ec_lpc_mec_destroy);
diff --git a/drivers/platform/chrome/cros_ec_lpc_reg.c b/drivers/platform/chrome/cros_ec_lpc_reg.c
index 03c9781..dcc7a3e 100644
--- a/drivers/platform/chrome/cros_ec_lpc_reg.c
+++ b/drivers/platform/chrome/cros_ec_lpc_reg.c
@@ -24,6 +24,7 @@
#include <linux/io.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
+#include <linux/mfd/cros_ec_lpc_mec.h>

static u8 lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
{
@@ -53,12 +54,80 @@ static u8 lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
return sum;
}

+#ifdef CONFIG_CROS_EC_LPC_MEC
+
u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
{
+ if (length == 0)
+ return 0;
+
+ /* Access desired range through EMI interface */
+ if (offset >= MEC_EMI_RANGE_START && offset <= MEC_EMI_RANGE_END) {
+ /* Ensure we don't straddle EMI region */
+ if (WARN_ON(offset + length - 1 > MEC_EMI_RANGE_END))
+ return 0;
+
+ return cros_ec_lpc_io_bytes_mec(MEC_IO_READ, offset, length,
+ dest);
+ }
+
+ if (WARN_ON(offset + length > MEC_EMI_RANGE_START &&
+ offset < MEC_EMI_RANGE_START))
+ return 0;
+
return lpc_read_bytes(offset, length, dest);
}

u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
{
+ if (length == 0)
+ return 0;
+
+ /* Access desired range through EMI interface */
+ if (offset >= MEC_EMI_RANGE_START && offset <= MEC_EMI_RANGE_END) {
+ /* Ensure we don't straddle EMI region */
+ if (WARN_ON(offset + length - 1 > MEC_EMI_RANGE_END))
+ return 0;
+
+ return cros_ec_lpc_io_bytes_mec(MEC_IO_WRITE, offset, length,
+ msg);
+ }
+
+ if (WARN_ON(offset + length > MEC_EMI_RANGE_START &&
+ offset < MEC_EMI_RANGE_START))
+ return 0;
+
return lpc_write_bytes(offset, length, msg);
}
+
+void cros_ec_lpc_reg_init(void)
+{
+ cros_ec_lpc_mec_init();
+}
+
+void cros_ec_lpc_reg_destroy(void)
+{
+ cros_ec_lpc_mec_destroy();
+}
+
+#else /* CONFIG_CROS_EC_LPC_MEC */
+
+u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
+{
+ return lpc_read_bytes(offset, length, dest);
+}
+
+u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
+{
+ return lpc_write_bytes(offset, length, msg);
+}
+
+void cros_ec_lpc_reg_init(void)
+{
+}
+
+void cros_ec_lpc_reg_destroy(void)
+{
+}
+
+#endif /* CONFIG_CROS_EC_LPC_MEC */
diff --git a/include/linux/mfd/cros_ec_lpc_mec.h b/include/linux/mfd/cros_ec_lpc_mec.h
new file mode 100644
index 0000000..176496d
--- /dev/null
+++ b/include/linux/mfd/cros_ec_lpc_mec.h
@@ -0,0 +1,90 @@
+/*
+ * cros_ec_lpc_mec - LPC variant I/O for Microchip EC
+ *
+ * Copyright (C) 2016 Google, Inc
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * This driver uses the Chrome OS EC byte-level message-based protocol for
+ * communicating the keyboard state (which keys are pressed) from a keyboard EC
+ * to the AP over some bus (such as i2c, lpc, spi). The EC does debouncing,
+ * but everything else (including deghosting) is done here. The main
+ * motivation for this is to keep the EC firmware as simple as possible, since
+ * it cannot be easily upgraded and EC flash/IRAM space is relatively
+ * expensive.
+ */
+
+#ifndef __LINUX_MFD_CROS_EC_MEC_H
+#define __LINUX_MFD_CROS_EC_MEC_H
+
+#include <linux/mfd/cros_ec_commands.h>
+
+enum cros_ec_lpc_mec_emi_access_mode {
+ /* 8-bit access */
+ ACCESS_TYPE_BYTE = 0x0,
+ /* 16-bit access */
+ ACCESS_TYPE_WORD = 0x1,
+ /* 32-bit access */
+ ACCESS_TYPE_LONG = 0x2,
+ /*
+ * 32-bit access, read or write of MEC_EMI_EC_DATA_B3 causes the
+ * EC data register to be incremented.
+ */
+ ACCESS_TYPE_LONG_AUTO_INCREMENT = 0x3,
+};
+
+enum cros_ec_lpc_mec_io_type {
+ MEC_IO_READ,
+ MEC_IO_WRITE,
+};
+
+/* Access IO ranges 0x800 thru 0x9ff using EMI interface instead of LPC */
+#define MEC_EMI_RANGE_START EC_HOST_CMD_REGION0
+#define MEC_EMI_RANGE_END (EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SIZE)
+
+/* EMI registers are relative to base */
+#define MEC_EMI_BASE 0x800
+#define MEC_EMI_HOST_TO_EC (MEC_EMI_BASE + 0)
+#define MEC_EMI_EC_TO_HOST (MEC_EMI_BASE + 1)
+#define MEC_EMI_EC_ADDRESS_B0 (MEC_EMI_BASE + 2)
+#define MEC_EMI_EC_ADDRESS_B1 (MEC_EMI_BASE + 3)
+#define MEC_EMI_EC_DATA_B0 (MEC_EMI_BASE + 4)
+#define MEC_EMI_EC_DATA_B1 (MEC_EMI_BASE + 5)
+#define MEC_EMI_EC_DATA_B2 (MEC_EMI_BASE + 6)
+#define MEC_EMI_EC_DATA_B3 (MEC_EMI_BASE + 7)
+
+/*
+ * cros_ec_lpc_mec_init
+ *
+ * Initialize MEC I/O.
+ */
+void cros_ec_lpc_mec_init(void);
+
+/*
+ * cros_ec_lpc_mec_destroy
+ *
+ * Cleanup MEC I/O.
+ */
+void cros_ec_lpc_mec_destroy(void);
+
+/**
+ * cros_ec_lpc_io_bytes_mec - Read / write bytes to MEC EMI port
+ *
+ * @io_type: MEC_IO_READ or MEC_IO_WRITE, depending on request
+ * @offset: Base read / write address
+ * @length: Number of bytes to read / write
+ * @buf: Destination / source buffer
+ *
+ * @return 8-bit checksum of all bytes read / written
+ */
+u8 cros_ec_lpc_io_bytes_mec(enum cros_ec_lpc_mec_io_type io_type,
+ unsigned int offset, unsigned int length, u8 *buf);
+
+#endif /* __LINUX_MFD_CROS_EC_MEC_H */
diff --git a/include/linux/mfd/cros_ec_lpc_reg.h b/include/linux/mfd/cros_ec_lpc_reg.h
index 4089bd5..5560bef 100644
--- a/include/linux/mfd/cros_ec_lpc_reg.h
+++ b/include/linux/mfd/cros_ec_lpc_reg.h
@@ -44,4 +44,18 @@ u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest);
*/
u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg);

+/**
+ * cros_ec_lpc_reg_init
+ *
+ * Initialize register I/O.
+ */
+void cros_ec_lpc_reg_init(void);
+
+/**
+ * cros_ec_lpc_reg_destroy
+ *
+ * Cleanup reg I/O.
+ */
+void cros_ec_lpc_reg_destroy(void);
+
#endif /* __LINUX_MFD_CROS_EC_REG_H */
--
2.9.3
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