i2c: add Tegra186 BPMP driver

On Tegra186, some I2C controllers are directly controlled by the main CPU,
whereas others are controlled by the BPMP, and can only be accessed by the
main CPU via IPC requests to the BPMP. This driver covers the latter case.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Tom Warren <twarren@nvidia.com>

drivers/i2c/Kconfig

@@ -161,6 +161,16 @@ config SYS_I2C_MVTWSI
 	  Support for Marvell I2C controllers as used on the orion5x and
 	  kirkwood SoC families.
 
+config TEGRA186_BPMP_I2C
+	bool "Enable Tegra186 BPMP-based I2C driver"
+	depends on TEGRA186_BPMP
+	help
+	  Support for Tegra I2C controllers managed by the BPMP (Boot and
+	  Power Management Processor). On Tegra186, some I2C controllers are
+	  directly controlled by the main CPU, whereas others are controlled
+	  by the BPMP, and can only be accessed by the main CPU via IPC
+	  requests to the BPMP. This driver covers the latter case.
+
 source "drivers/i2c/muxes/Kconfig"
 
 endmenu

drivers/i2c/Makefile

@@ -41,5 +41,6 @@ obj-$(CONFIG_SYS_I2C_TEGRA) += tegra_i2c.o
 obj-$(CONFIG_SYS_I2C_UNIPHIER) += i2c-uniphier.o
 obj-$(CONFIG_SYS_I2C_UNIPHIER_F) += i2c-uniphier-f.o
 obj-$(CONFIG_SYS_I2C_ZYNQ) += zynq_i2c.o
+obj-$(CONFIG_TEGRA186_BPMP_I2C) += tegra186_bpmp_i2c.o
 
 obj-$(CONFIG_I2C_MUX) += muxes/

drivers/i2c/tegra186_bpmp_i2c.c

@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2016, NVIDIA CORPORATION.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <i2c.h>
+#include <misc.h>
+#include <asm/arch-tegra/bpmp_abi.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct tegra186_bpmp_i2c {
+	uint32_t bpmp_bus_id;
+};
+
+static inline void serialize_u16(uint8_t **p, uint16_t val)
+{
+	(*p)[0] = val & 0xff;
+	(*p)[1] = val >> 8;
+	(*p) += 2;
+}
+
+/* These just happen to have the same values as I2C_M_* and SERIALI2C_* */
+#define SUPPORTED_FLAGS \
+	(I2C_M_TEN | \
+	I2C_M_RD | \
+	I2C_M_STOP | \
+	I2C_M_NOSTART | \
+	I2C_M_REV_DIR_ADDR | \
+	I2C_M_IGNORE_NAK | \
+	I2C_M_NO_RD_ACK | \
+	I2C_M_RECV_LEN)
+
+static int tegra186_bpmp_i2c_xfer(struct udevice *dev, struct i2c_msg *msg,
+				  int nmsgs)
+{
+	struct tegra186_bpmp_i2c *priv = dev_get_priv(dev);
+	struct mrq_i2c_request req;
+	struct mrq_i2c_response resp;
+	uint8_t *p;
+	int left, i, ret;
+
+	req.cmd = CMD_I2C_XFER;
+	req.xfer.bus_id = priv->bpmp_bus_id;
+	p = &req.xfer.data_buf[0];
+	left = ARRAY_SIZE(req.xfer.data_buf);
+	for (i = 0; i < nmsgs; i++) {
+		int len = 6;
+		if (!(msg[i].flags & I2C_M_RD))
+			len += msg[i].len;
+		if ((len >= BIT(16)) || (len > left))
+			return -ENOSPC;
+
+		if (msg[i].flags & ~SUPPORTED_FLAGS)
+			return -EINVAL;
+
+		serialize_u16(&p, msg[i].addr);
+		serialize_u16(&p, msg[i].flags);
+		serialize_u16(&p, msg[i].len);
+		if (!(msg[i].flags & I2C_M_RD)) {
+			memcpy(p, msg[i].buf, msg[i].len);
+			p += msg[i].len;
+		}
+	}
+	req.xfer.data_size = p - &req.xfer.data_buf[0];
+
+	ret = misc_call(dev->parent, MRQ_I2C, &req, sizeof(req), &resp,
+			sizeof(resp));
+	if (ret < 0)
+		return ret;
+
+	p = &resp.xfer.data_buf[0];
+	left = resp.xfer.data_size;
+	if (left > ARRAY_SIZE(resp.xfer.data_buf))
+		return -EINVAL;
+	for (i = 0; i < nmsgs; i++) {
+		if (msg[i].flags & I2C_M_RD) {
+			memcpy(msg[i].buf, p, msg[i].len);
+			p += msg[i].len;
+		}
+	}
+
+	return 0;
+}
+
+static int tegra186_bpmp_i2c_probe(struct udevice *dev)
+{
+	struct tegra186_bpmp_i2c *priv = dev_get_priv(dev);
+	int ret;
+	struct fdtdec_phandle_args args;
+
+	ret = fdtdec_parse_phandle_with_args(gd->fdt_blob, dev->of_offset,
+					     "nvidia,bpmp", NULL, 0, 0, &args);
+	if (ret < 0) {
+		debug("%s: fdtdec_parse_phandle_with_args() failed: %d\n",
+		      __func__, ret);
+		return ret;
+	}
+
+	priv->bpmp_bus_id = fdtdec_get_uint(gd->fdt_blob, dev->of_offset,
+					    "nvidia,bpmp-bus-id", U32_MAX);
+	if (priv->bpmp_bus_id == U32_MAX) {
+		debug("%s: could not parse nvidia,bpmp-bus-id\n", __func__);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static const struct dm_i2c_ops tegra186_bpmp_i2c_ops = {
+	.xfer = tegra186_bpmp_i2c_xfer,
+};
+
+static const struct udevice_id tegra186_bpmp_i2c_ids[] = {
+	{ .compatible = "nvidia,tegra186-bpmp-i2c" },
+	{ }
+};
+
+U_BOOT_DRIVER(i2c_gpio) = {
+	.name	= "tegra186_bpmp_i2c",
+	.id	= UCLASS_I2C,
+	.of_match = tegra186_bpmp_i2c_ids,
+	.probe	= tegra186_bpmp_i2c_probe,
+	.priv_auto_alloc_size = sizeof(struct tegra186_bpmp_i2c),
+	.ops	= &tegra186_bpmp_i2c_ops,
+};