platform/chrome: cros_ec_lpc: Add R/W helpers to LPC protocol variants
authorShawn Nematbakhsh <shawnn@chromium.org>
Tue, 16 May 2017 15:46:48 +0000 (17:46 +0200)
committerBenson Leung <bleung@chromium.org>
Fri, 23 Jun 2017 23:09:06 +0000 (16:09 -0700)
Call common functions for read / write to prepare support for future
LPC protocol variants which use different I/O ops than inb / outb.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Benson Leung <bleung@chromium.org>
drivers/platform/chrome/Makefile
drivers/platform/chrome/cros_ec_lpc.c
drivers/platform/chrome/cros_ec_lpc_reg.c [new file with mode: 0644]
include/linux/mfd/cros_ec_lpc_reg.h [new file with mode: 0644]

index 3870afe..61182fd 100644 (file)
@@ -5,6 +5,7 @@ cros_ec_devs-objs                       := cros_ec_dev.o cros_ec_sysfs.o \
                                           cros_ec_lightbar.o cros_ec_vbc.o \
                                           cros_ec_debugfs.o
 obj-$(CONFIG_CROS_EC_CHARDEV)          += cros_ec_devs.o
-obj-$(CONFIG_CROS_EC_LPC)              += cros_ec_lpc.o
+cros_ec_lpcs-objs                      := cros_ec_lpc.o cros_ec_lpc_reg.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
index f9a2454..6a782a6 100644 (file)
 #include <linux/io.h>
 #include <linux/mfd/cros_ec.h>
 #include <linux/mfd/cros_ec_commands.h>
+#include <linux/mfd/cros_ec_lpc_reg.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/printk.h>
 
-#define DRV_NAME "cros_ec_lpc"
+#define DRV_NAME "cros_ec_lpcs"
 
 static int ec_response_timed_out(void)
 {
        unsigned long one_second = jiffies + HZ;
+       u8 data;
 
        usleep_range(200, 300);
        do {
-               if (!(inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK))
+               if (!(cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_CMD, 1, &data) &
+                   EC_LPC_STATUS_BUSY_MASK))
                        return 0;
                usleep_range(100, 200);
        } while (time_before(jiffies, one_second));
@@ -51,21 +54,20 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
 {
        struct ec_host_request *request;
        struct ec_host_response response;
-       u8 sum = 0;
-       int i;
+       u8 sum;
        int ret = 0;
        u8 *dout;
 
        ret = cros_ec_prepare_tx(ec, msg);
 
        /* Write buffer */
-       for (i = 0; i < ret; i++)
-               outb(ec->dout[i], EC_LPC_ADDR_HOST_PACKET + i);
+       cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_PACKET, ret, ec->dout);
 
        request = (struct ec_host_request *)ec->dout;
 
        /* Here we go */
-       outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD);
+       sum = EC_COMMAND_PROTOCOL_3;
+       cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_CMD, 1, &sum);
 
        if (ec_response_timed_out()) {
                dev_warn(ec->dev, "EC responsed timed out\n");
@@ -74,17 +76,15 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
        }
 
        /* Check result */
-       msg->result = inb(EC_LPC_ADDR_HOST_DATA);
+       msg->result = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_DATA, 1, &sum);
        ret = cros_ec_check_result(ec, msg);
        if (ret)
                goto done;
 
        /* Read back response */
        dout = (u8 *)&response;
-       for (i = 0; i < sizeof(response); i++) {
-               dout[i] = inb(EC_LPC_ADDR_HOST_PACKET + i);
-               sum += dout[i];
-       }
+       sum = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PACKET, sizeof(response),
+                                    dout);
 
        msg->result = response.result;
 
@@ -97,11 +97,9 @@ static int cros_ec_pkt_xfer_lpc(struct cros_ec_device *ec,
        }
 
        /* Read response and process checksum */
-       for (i = 0; i < response.data_len; i++) {
-               msg->data[i] =
-                       inb(EC_LPC_ADDR_HOST_PACKET + sizeof(response) + i);
-               sum += msg->data[i];
-       }
+       sum += cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PACKET +
+                                     sizeof(response), response.data_len,
+                                     msg->data);
 
        if (sum) {
                dev_err(ec->dev,
@@ -121,8 +119,7 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
                                struct cros_ec_command *msg)
 {
        struct ec_lpc_host_args args;
-       int csum;
-       int i;
+       u8 sum;
        int ret = 0;
 
        if (msg->outsize > EC_PROTO2_MAX_PARAM_SIZE ||
@@ -139,24 +136,20 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
        args.data_size = msg->outsize;
 
        /* Initialize checksum */
-       csum = msg->command + args.flags +
-               args.command_version + args.data_size;
+       sum = msg->command + args.flags + args.command_version + args.data_size;
 
        /* Copy data and update checksum */
-       for (i = 0; i < msg->outsize; i++) {
-               outb(msg->data[i], EC_LPC_ADDR_HOST_PARAM + i);
-               csum += msg->data[i];
-       }
+       sum += cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_PARAM, msg->outsize,
+                                      msg->data);
 
        /* Finalize checksum and write args */
-       args.checksum = csum & 0xFF;
-       outb(args.flags, EC_LPC_ADDR_HOST_ARGS);
-       outb(args.command_version, EC_LPC_ADDR_HOST_ARGS + 1);
-       outb(args.data_size, EC_LPC_ADDR_HOST_ARGS + 2);
-       outb(args.checksum, EC_LPC_ADDR_HOST_ARGS + 3);
+       args.checksum = sum;
+       cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
+                               (u8 *)&args);
 
        /* Here we go */
-       outb(msg->command, EC_LPC_ADDR_HOST_CMD);
+       sum = msg->command;
+       cros_ec_lpc_write_bytes(EC_LPC_ADDR_HOST_CMD, 1, &sum);
 
        if (ec_response_timed_out()) {
                dev_warn(ec->dev, "EC responsed timed out\n");
@@ -165,16 +158,14 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
        }
 
        /* Check result */
-       msg->result = inb(EC_LPC_ADDR_HOST_DATA);
+       msg->result = cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_DATA, 1, &sum);
        ret = cros_ec_check_result(ec, msg);
        if (ret)
                goto done;
 
        /* Read back args */
-       args.flags = inb(EC_LPC_ADDR_HOST_ARGS);
-       args.command_version = inb(EC_LPC_ADDR_HOST_ARGS + 1);
-       args.data_size = inb(EC_LPC_ADDR_HOST_ARGS + 2);
-       args.checksum = inb(EC_LPC_ADDR_HOST_ARGS + 3);
+       cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_ARGS, sizeof(args),
+                              (u8 *)&args);
 
        if (args.data_size > msg->insize) {
                dev_err(ec->dev,
@@ -185,20 +176,17 @@ static int cros_ec_cmd_xfer_lpc(struct cros_ec_device *ec,
        }
 
        /* Start calculating response checksum */
-       csum = msg->command + args.flags +
-               args.command_version + args.data_size;
+       sum = msg->command + args.flags + args.command_version + args.data_size;
 
        /* Read response and update checksum */
-       for (i = 0; i < args.data_size; i++) {
-               msg->data[i] = inb(EC_LPC_ADDR_HOST_PARAM + i);
-               csum += msg->data[i];
-       }
+       sum += cros_ec_lpc_read_bytes(EC_LPC_ADDR_HOST_PARAM, args.data_size,
+                                     msg->data);
 
        /* Verify checksum */
-       if (args.checksum != (csum & 0xFF)) {
+       if (args.checksum != sum) {
                dev_err(ec->dev,
                        "bad packet checksum, expected %02x, got %02x\n",
-                       args.checksum, csum & 0xFF);
+                       args.checksum, sum);
                ret = -EBADMSG;
                goto done;
        }
@@ -222,14 +210,13 @@ static int cros_ec_lpc_readmem(struct cros_ec_device *ec, unsigned int offset,
 
        /* fixed length */
        if (bytes) {
-               for (; cnt < bytes; i++, s++, cnt++)
-                       *s = inb(EC_LPC_ADDR_MEMMAP + i);
-               return cnt;
+               cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + offset, bytes, s);
+               return bytes;
        }
 
        /* string */
        for (; i < EC_MEMMAP_SIZE; i++, s++) {
-               *s = inb(EC_LPC_ADDR_MEMMAP + i);
+               cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + i, 1, s);
                cnt++;
                if (!*s)
                        break;
@@ -242,6 +229,7 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
        struct cros_ec_device *ec_dev;
+       u8 buf[2];
        int ret;
 
        if (!devm_request_region(dev, EC_LPC_ADDR_MEMMAP, EC_MEMMAP_SIZE,
@@ -250,8 +238,8 @@ static int cros_ec_lpc_probe(struct platform_device *pdev)
                return -EBUSY;
        }
 
-       if ((inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E') ||
-           (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C')) {
+       cros_ec_lpc_read_bytes(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID, 2, buf);
+       if (buf[0] != 'E' || buf[1] != 'C') {
                dev_err(dev, "EC ID not detected\n");
                return -ENODEV;
        }
diff --git a/drivers/platform/chrome/cros_ec_lpc_reg.c b/drivers/platform/chrome/cros_ec_lpc_reg.c
new file mode 100644 (file)
index 0000000..03c9781
--- /dev/null
@@ -0,0 +1,64 @@
+/*
+ * cros_ec_lpc_reg - LPC access to the Chrome OS Embedded Controller
+ *
+ * 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/io.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+
+static u8 lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest)
+{
+       int i;
+       int sum = 0;
+
+       for (i = 0; i < length; ++i) {
+               dest[i] = inb(offset + i);
+               sum += dest[i];
+       }
+
+       /* Return checksum of all bytes read */
+       return sum;
+}
+
+static u8 lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg)
+{
+       int i;
+       int sum = 0;
+
+       for (i = 0; i < length; ++i) {
+               outb(msg[i], offset + i);
+               sum += msg[i];
+       }
+
+       /* Return checksum of all bytes written */
+       return sum;
+}
+
+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);
+}
diff --git a/include/linux/mfd/cros_ec_lpc_reg.h b/include/linux/mfd/cros_ec_lpc_reg.h
new file mode 100644 (file)
index 0000000..4089bd5
--- /dev/null
@@ -0,0 +1,47 @@
+/*
+ * cros_ec_lpc_reg - LPC access to the Chrome OS Embedded Controller
+ *
+ * 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_REG_H
+#define __LINUX_MFD_CROS_EC_REG_H
+
+/**
+ * cros_ec_lpc_read_bytes - Read bytes from a given LPC-mapped address.
+ * Returns 8-bit checksum of all bytes read.
+ *
+ * @offset: Base read address
+ * @length: Number of bytes to read
+ * @dest: Destination buffer
+ */
+u8 cros_ec_lpc_read_bytes(unsigned int offset, unsigned int length, u8 *dest);
+
+/**
+ * cros_ec_lpc_write_bytes - Write bytes to a given LPC-mapped address.
+ * Returns 8-bit checksum of all bytes written.
+ *
+ * @offset: Base write address
+ * @length: Number of bytes to write
+ * @msg: Write data buffer
+ */
+u8 cros_ec_lpc_write_bytes(unsigned int offset, unsigned int length, u8 *msg);
+
+#endif /* __LINUX_MFD_CROS_EC_REG_H */