[U-Boot] [PATCH 4/7] i2c: add Tegra186 BPMP driver

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

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 at nvidia.com>
---
 drivers/i2c/Kconfig             |  10 ++++
 drivers/i2c/Makefile            |   1 +
 drivers/i2c/tegra186_bpmp_i2c.c | 129 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 drivers/i2c/tegra186_bpmp_i2c.c

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 6e22bbadff2d..68d3956e473c 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -154,6 +154,16 @@ config SYS_I2C_UNIPHIER_F
 	  Support for UniPhier FIFO-builtin I2C controller driver.
 	  This I2C controller is used on PH1-Pro4 or newer UniPhier SoCs.
 
+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
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index 167424db9820..97b6bedde822 100644
--- a/drivers/i2c/Makefile
+++ b/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/
diff --git a/drivers/i2c/tegra186_bpmp_i2c.c b/drivers/i2c/tegra186_bpmp_i2c.c
new file mode 100644
index 000000000000..d3b3edffb53f
--- /dev/null
+++ b/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 <asm/arch-tegra/bpmp_abi.h>
+#include <asm/arch-tegra/tegra186_bpmp.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 = tegra186_bpmp_call(dev->parent, MRQ_I2C,
+				 &req, sizeof(req), &resp, sizeof(resp));
+	if (ret)
+		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,
+};
-- 
2.9.2