1 files changed, 346 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-tegra-bpmp.c b/drivers/i2c/busses/i2c-tegra-bpmp.c
new file mode 100644
index 000000000000..9eed69d5e17e
--- /dev/null
+++ b/drivers/i2c/busses/i2c-tegra-bpmp.c
@@ -0,0 +1,346 @@
+/*
+ * drivers/i2c/busses/i2c-tegra-bpmp.c
+ *
+ * Copyright (c) 2016 NVIDIA Corporation.  All rights reserved.
+ *
+ * Author: Shardar Shariff Md <smohammed@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include <soc/tegra/bpmp-abi.h>
+#include <soc/tegra/bpmp.h>
+
+/*
+ * Serialized I2C message header size is 6 bytes and includes address, flags
+ * and length
+ */
+#define SERIALI2C_HDR_SIZE 6
+
+struct tegra_bpmp_i2c {
+	struct i2c_adapter adapter;
+	struct device *dev;
+
+	struct tegra_bpmp *bpmp;
+	unsigned int bus;
+};
+
+/*
+ * Linux flags are translated to BPMP defined I2C flags that are used in BPMP
+ * firmware I2C driver to avoid any issues in future if Linux I2C flags are
+ * changed.
+ */
+static int tegra_bpmp_xlate_flags(u16 flags, u16 *out)
+{
+	if (flags & I2C_M_TEN) {
+		*out |= SERIALI2C_TEN;
+		flags &= ~I2C_M_TEN;
+	}
+
+	if (flags & I2C_M_RD) {
+		*out |= SERIALI2C_RD;
+		flags &= ~I2C_M_RD;
+	}
+
+	if (flags & I2C_M_STOP) {
+		*out |= SERIALI2C_STOP;
+		flags &= ~I2C_M_STOP;
+	}
+
+	if (flags & I2C_M_NOSTART) {
+		*out |= SERIALI2C_NOSTART;
+		flags &= ~I2C_M_NOSTART;
+	}
+
+	if (flags & I2C_M_REV_DIR_ADDR) {
+		*out |= SERIALI2C_REV_DIR_ADDR;
+		flags &= ~I2C_M_REV_DIR_ADDR;
+	}
+
+	if (flags & I2C_M_IGNORE_NAK) {
+		*out |= SERIALI2C_IGNORE_NAK;
+		flags &= ~I2C_M_IGNORE_NAK;
+	}
+
+	if (flags & I2C_M_NO_RD_ACK) {
+		*out |= SERIALI2C_NO_RD_ACK;
+		flags &= ~I2C_M_NO_RD_ACK;
+	}
+
+	if (flags & I2C_M_RECV_LEN) {
+		*out |= SERIALI2C_RECV_LEN;
+		flags &= ~I2C_M_RECV_LEN;
+	}
+
+	return (flags != 0) ? -EINVAL : 0;
+}
+
+/**
+ * The serialized I2C format is simply the following:
+ * [addr little-endian][flags little-endian][len little-endian][data if write]
+ * [addr little-endian][flags little-endian][len little-endian][data if write]
+ *  ...
+ *
+ * The flags are translated from Linux kernel representation to seriali2c
+ * representation. Any undefined flag being set causes an error.
+ *
+ * The data is there only for writes. Reads have the data transferred in the
+ * other direction, and thus data is not present.
+ *
+ * See deserialize_i2c documentation for the data format in the other direction.
+ */
+static int tegra_bpmp_serialize_i2c_msg(struct tegra_bpmp_i2c *i2c,
+					struct mrq_i2c_request *request,
+					struct i2c_msg *msgs,
+					unsigned int num)
+{
+	char *buf = request->xfer.data_buf;
+	unsigned int i, j, pos = 0;
+	int err;
+
+	for (i = 0; i < num; i++) {
+		struct i2c_msg *msg = &msgs[i];
+		u16 flags = 0;
+
+		err = tegra_bpmp_xlate_flags(msg->flags, &flags);
+		if (err < 0)
+			return err;
+
+		buf[pos++] = msg->addr & 0xff;
+		buf[pos++] = (msg->addr & 0xff00) >> 8;
+		buf[pos++] = flags & 0xff;
+		buf[pos++] = (flags & 0xff00) >> 8;
+		buf[pos++] = msg->len & 0xff;
+		buf[pos++] = (msg->len & 0xff00) >> 8;
+
+		if ((flags & SERIALI2C_RD) == 0) {
+			for (j = 0; j < msg->len; j++)
+				buf[pos++] = msg->buf[j];
+		}
+	}
+
+	request->xfer.data_size = pos;
+
+	return 0;
+}
+
+/**
+ * The data in the BPMP -> CPU direction is composed of sequential blocks for
+ * those messages that have I2C_M_RD. So, for example, if you have:
+ *
+ * - !I2C_M_RD, len == 5, data == a0 01 02 03 04
+ * - !I2C_M_RD, len == 1, data == a0
+ * - I2C_M_RD, len == 2, data == [uninitialized buffer 1]
+ * - !I2C_M_RD, len == 1, data == a2
+ * - I2C_M_RD, len == 2, data == [uninitialized buffer 2]
+ *
+ * ...then the data in the BPMP -> CPU direction would be 4 bytes total, and
+ * would contain 2 bytes that will go to uninitialized buffer 1, and 2 bytes
+ * that will go to uninitialized buffer 2.
+ */
+static int tegra_bpmp_i2c_deserialize(struct tegra_bpmp_i2c *i2c,
+				      struct mrq_i2c_response *response,
+				      struct i2c_msg *msgs,
+				      unsigned int num)
+{
+	size_t size = response->xfer.data_size, len = 0, pos = 0;
+	char *buf = response->xfer.data_buf;
+	unsigned int i;
+
+	for (i = 0; i < num; i++)
+		if (msgs[i].flags & I2C_M_RD)
+			len += msgs[i].len;
+
+	if (len != size)
+		return -EINVAL;
+
+	for (i = 0; i < num; i++) {
+		if (msgs[i].flags & I2C_M_RD) {
+			memcpy(msgs[i].buf, buf + pos, msgs[i].len);
+			pos += msgs[i].len;
+		}
+	}
+
+	return 0;
+}
+
+static int tegra_bpmp_i2c_msg_len_check(struct i2c_msg *msgs, unsigned int num)
+{
+	size_t tx_len = 0, rx_len = 0;
+	unsigned int i;
+
+	for (i = 0; i < num; i++)
+		if (!(msgs[i].flags & I2C_M_RD))
+			tx_len += SERIALI2C_HDR_SIZE + msgs[i].len;
+
+	if (tx_len > TEGRA_I2C_IPC_MAX_IN_BUF_SIZE)
+		return -EINVAL;
+
+	for (i = 0; i < num; i++)
+		if ((msgs[i].flags & I2C_M_RD))
+			rx_len += msgs[i].len;
+
+	if (rx_len > TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int tegra_bpmp_i2c_msg_xfer(struct tegra_bpmp_i2c *i2c,
+				   struct mrq_i2c_request *request,
+				   struct mrq_i2c_response *response)
+{
+	struct tegra_bpmp_message msg;
+	int err;
+
+	request->cmd = CMD_I2C_XFER;
+	request->xfer.bus_id = i2c->bus;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.mrq = MRQ_I2C;
+	msg.tx.data = request;
+	msg.tx.size = sizeof(*request);
+	msg.rx.data = response;
+	msg.rx.size = sizeof(*response);
+
+	if (irqs_disabled())
+		err = tegra_bpmp_transfer_atomic(i2c->bpmp, &msg);
+	else
+		err = tegra_bpmp_transfer(i2c->bpmp, &msg);
+
+	return err;
+}
+
+static int tegra_bpmp_i2c_xfer(struct i2c_adapter *adapter,
+			       struct i2c_msg *msgs, int num)
+{
+	struct tegra_bpmp_i2c *i2c = i2c_get_adapdata(adapter);
+	struct mrq_i2c_response response;
+	struct mrq_i2c_request request;
+	int err;
+
+	err = tegra_bpmp_i2c_msg_len_check(msgs, num);
+	if (err < 0) {
+		dev_err(i2c->dev, "unsupported message length\n");
+		return err;
+	}
+
+	memset(&request, 0, sizeof(request));
+	memset(&response, 0, sizeof(response));
+
+	err = tegra_bpmp_serialize_i2c_msg(i2c, &request, msgs, num);
+	if (err < 0) {
+		dev_err(i2c->dev, "failed to serialize message: %d\n", err);
+		return err;
+	}
+
+	err = tegra_bpmp_i2c_msg_xfer(i2c, &request, &response);
+	if (err < 0) {
+		dev_err(i2c->dev, "failed to transfer message: %d\n", err);
+		return err;
+	}
+
+	err = tegra_bpmp_i2c_deserialize(i2c, &response, msgs, num);
+	if (err < 0) {
+		dev_err(i2c->dev, "failed to deserialize message: %d\n", err);
+		return err;
+	}
+
+	return num;
+}
+
+static u32 tegra_bpmp_i2c_func(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR |
+	       I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_NOSTART;
+}
+
+static const struct i2c_algorithm tegra_bpmp_i2c_algo = {
+	.master_xfer = tegra_bpmp_i2c_xfer,
+	.functionality = tegra_bpmp_i2c_func,
+};
+
+static int tegra_bpmp_i2c_probe(struct platform_device *pdev)
+{
+	struct tegra_bpmp_i2c *i2c;
+	u32 value;
+	int err;
+
+	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
+	if (!i2c)
+		return -ENOMEM;
+
+	i2c->dev = &pdev->dev;
+
+	i2c->bpmp = dev_get_drvdata(pdev->dev.parent);
+	if (!i2c->bpmp)
+		return -ENODEV;
+
+	err = of_property_read_u32(pdev->dev.of_node, "nvidia,bpmp-bus-id",
+				   &value);
+	if (err < 0)
+		return err;
+
+	i2c->bus = value;
+
+	i2c_set_adapdata(&i2c->adapter, i2c);
+	i2c->adapter.owner = THIS_MODULE;
+	strlcpy(i2c->adapter.name, "Tegra BPMP I2C adapter",
+		sizeof(i2c->adapter.name));
+	i2c->adapter.algo = &tegra_bpmp_i2c_algo;
+	i2c->adapter.dev.parent = &pdev->dev;
+	i2c->adapter.dev.of_node = pdev->dev.of_node;
+
+	platform_set_drvdata(pdev, i2c);
+
+	return i2c_add_adapter(&i2c->adapter);
+}
+
+static int tegra_bpmp_i2c_remove(struct platform_device *pdev)
+{
+	struct tegra_bpmp_i2c *i2c = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&i2c->adapter);
+
+	return 0;
+}
+
+static const struct of_device_id tegra_bpmp_i2c_of_match[] = {
+	{ .compatible = "nvidia,tegra186-bpmp-i2c", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tegra_bpmp_i2c_of_match);
+
+static struct platform_driver tegra_bpmp_i2c_driver = {
+	.driver = {
+		.name = "tegra-bpmp-i2c",
+		.of_match_table = tegra_bpmp_i2c_of_match,
+	},
+	.probe = tegra_bpmp_i2c_probe,
+	.remove = tegra_bpmp_i2c_remove,
+};
+module_platform_driver(tegra_bpmp_i2c_driver);
+
+MODULE_DESCRIPTION("NVIDIA Tegra BPMP I2C bus contoller driver");
+MODULE_AUTHOR("Shardar Shariff Md <smohammed@nvidia.com>");
+MODULE_AUTHOR("Juha-Matti Tilli");
+MODULE_LICENSE("GPL v2");