i3c/master: introduce the mipi-i3c-hci driver

This adds basic support for hardware implementing the MIPI I3C HCI
specification. This driver is currently limited by the capabilities
of the I3C subsystem, meaning things like scheduled commands,
auto-commands and NCM mode are not yet supported.

This supports version 1.0 of the MIPI I3C HCI spec, as well as the
imminent release of version 1.1. Support for draft version 2.0 of the
spec is also largely included with the caveat that future adjustments
to this code are likely as the spec is still a work in progress.

This is also lightly tested as actual hardware is still very scarce,
even for HCI v1.0. Hence the EXPERIMENTAL tag. Further contributions
to this driver are expected once vendor implementations and new I3C
devices become available.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://lore.kernel.org/linux-i3c/20201111220510.3622216-3-nico@fluxnic.net

1 files changed, 316 insertions, 0 deletions

diff --git a/drivers/i3c/master/mipi-i3c-hci/cmd_v2.c b/drivers/i3c/master/mipi-i3c-hci/cmd_v2.c
new file mode 100644
index 000000000000..4493b2b067cb
--- /dev/null
+++ b/drivers/i3c/master/mipi-i3c-hci/cmd_v2.c
@@ -0,0 +1,316 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright (c) 2020, MIPI Alliance, Inc.
+ *
+ * Author: Nicolas Pitre <npitre@baylibre.com>
+ *
+ * I3C HCI v2.0 Command Descriptor Handling
+ *
+ * Note: The I3C HCI v2.0 spec is still in flux. The code here will change.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/i3c/master.h>
+
+#include "hci.h"
+#include "cmd.h"
+#include "xfer_mode_rate.h"
+
+
+/*
+ * Unified Data Transfer Command
+ */
+
+#define CMD_0_ATTR_U			FIELD_PREP(CMD_0_ATTR, 0x4)
+
+#define CMD_U3_HDR_TSP_ML_CTRL(v)	FIELD_PREP(W3_MASK(107, 104), v)
+#define CMD_U3_IDB4(v)			FIELD_PREP(W3_MASK(103,  96), v)
+#define CMD_U3_HDR_CMD(v)		FIELD_PREP(W3_MASK(103,  96), v)
+#define CMD_U2_IDB3(v)			FIELD_PREP(W2_MASK( 95,  88), v)
+#define CMD_U2_HDR_BT(v)		FIELD_PREP(W2_MASK( 95,  88), v)
+#define CMD_U2_IDB2(v)			FIELD_PREP(W2_MASK( 87,  80), v)
+#define CMD_U2_BT_CMD2(v)		FIELD_PREP(W2_MASK( 87,  80), v)
+#define CMD_U2_IDB1(v)			FIELD_PREP(W2_MASK( 79,  72), v)
+#define CMD_U2_BT_CMD1(v)		FIELD_PREP(W2_MASK( 79,  72), v)
+#define CMD_U2_IDB0(v)			FIELD_PREP(W2_MASK( 71,  64), v)
+#define CMD_U2_BT_CMD0(v)		FIELD_PREP(W2_MASK( 71,  64), v)
+#define CMD_U1_ERR_HANDLING(v)		FIELD_PREP(W1_MASK( 63,  62), v)
+#define CMD_U1_ADD_FUNC(v)		FIELD_PREP(W1_MASK( 61,  56), v)
+#define CMD_U1_COMBO_XFER			   W1_BIT_( 55)
+#define CMD_U1_DATA_LENGTH(v)		FIELD_PREP(W1_MASK( 53,  32), v)
+#define CMD_U0_TOC				   W0_BIT_( 31)
+#define CMD_U0_ROC				   W0_BIT_( 30)
+#define CMD_U0_MAY_YIELD			   W0_BIT_( 29)
+#define CMD_U0_NACK_RCNT(v)		FIELD_PREP(W0_MASK( 28,  27), v)
+#define CMD_U0_IDB_COUNT(v)		FIELD_PREP(W0_MASK( 26,  24), v)
+#define CMD_U0_MODE_INDEX(v)		FIELD_PREP(W0_MASK( 22,  18), v)
+#define CMD_U0_XFER_RATE(v)		FIELD_PREP(W0_MASK( 17,  15), v)
+#define CMD_U0_DEV_ADDRESS(v)		FIELD_PREP(W0_MASK( 14,   8), v)
+#define CMD_U0_RnW				   W0_BIT_(  7)
+#define CMD_U0_TID(v)			FIELD_PREP(W0_MASK(  6,   3), v)
+
+/*
+ * Address Assignment Command
+ */
+
+#define CMD_0_ATTR_A			FIELD_PREP(CMD_0_ATTR, 0x2)
+
+#define CMD_A1_DATA_LENGTH(v)		FIELD_PREP(W1_MASK( 53,  32), v)
+#define CMD_A0_TOC				   W0_BIT_( 31)
+#define CMD_A0_ROC				   W0_BIT_( 30)
+#define CMD_A0_XFER_RATE(v)		FIELD_PREP(W0_MASK( 17,  15), v)
+#define CMD_A0_ASSIGN_ADDRESS(v)	FIELD_PREP(W0_MASK( 14,   8), v)
+#define CMD_A0_TID(v)			FIELD_PREP(W0_MASK(  6,   3), v)
+
+
+static unsigned int get_i3c_rate_idx(struct i3c_hci *hci)
+{
+	struct i3c_bus *bus = i3c_master_get_bus(&hci->master);
+
+	if (bus->scl_rate.i3c >= 12000000)
+		return XFERRATE_I3C_SDR0;
+	if (bus->scl_rate.i3c > 8000000)
+		return XFERRATE_I3C_SDR1;
+	if (bus->scl_rate.i3c > 6000000)
+		return XFERRATE_I3C_SDR2;
+	if (bus->scl_rate.i3c > 4000000)
+		return XFERRATE_I3C_SDR3;
+	if (bus->scl_rate.i3c > 2000000)
+		return XFERRATE_I3C_SDR4;
+	return XFERRATE_I3C_SDR_FM_FMP;
+}
+
+static unsigned int get_i2c_rate_idx(struct i3c_hci *hci)
+{
+	struct i3c_bus *bus = i3c_master_get_bus(&hci->master);
+
+	if (bus->scl_rate.i2c >= 1000000)
+		return XFERRATE_I2C_FMP;
+	return XFERRATE_I2C_FM;
+}
+
+static void hci_cmd_v2_prep_private_xfer(struct i3c_hci *hci,
+					 struct hci_xfer *xfer,
+					 u8 addr, unsigned int mode,
+					 unsigned int rate)
+{
+	u8 *data = xfer->data;
+	unsigned int data_len = xfer->data_len;
+	bool rnw = xfer->rnw;
+
+	xfer->cmd_tid = hci_get_tid();
+
+	if (!rnw && data_len <= 5) {
+		xfer->cmd_desc[0] =
+			CMD_0_ATTR_U |
+			CMD_U0_TID(xfer->cmd_tid) |
+			CMD_U0_DEV_ADDRESS(addr) |
+			CMD_U0_XFER_RATE(rate) |
+			CMD_U0_MODE_INDEX(mode) |
+			CMD_U0_IDB_COUNT(data_len);
+		xfer->cmd_desc[1] =
+			CMD_U1_DATA_LENGTH(0);
+		xfer->cmd_desc[2] = 0;
+		xfer->cmd_desc[3] = 0;
+		switch (data_len) {
+		case 5:
+			xfer->cmd_desc[3] |= CMD_U3_IDB4(data[4]);
+			fallthrough;
+		case 4:
+			xfer->cmd_desc[2] |= CMD_U2_IDB3(data[3]);
+			fallthrough;
+		case 3:
+			xfer->cmd_desc[2] |= CMD_U2_IDB2(data[2]);
+			fallthrough;
+		case 2:
+			xfer->cmd_desc[2] |= CMD_U2_IDB1(data[1]);
+			fallthrough;
+		case 1:
+			xfer->cmd_desc[2] |= CMD_U2_IDB0(data[0]);
+			fallthrough;
+		case 0:
+			break;
+		}
+		/* we consumed all the data with the cmd descriptor */
+		xfer->data = NULL;
+	} else {
+		xfer->cmd_desc[0] =
+			CMD_0_ATTR_U |
+			CMD_U0_TID(xfer->cmd_tid) |
+			(rnw ? CMD_U0_RnW : 0) |
+			CMD_U0_DEV_ADDRESS(addr) |
+			CMD_U0_XFER_RATE(rate) |
+			CMD_U0_MODE_INDEX(mode);
+		xfer->cmd_desc[1] =
+			CMD_U1_DATA_LENGTH(data_len);
+		xfer->cmd_desc[2] = 0;
+		xfer->cmd_desc[3] = 0;
+	}
+}
+
+static int hci_cmd_v2_prep_ccc(struct i3c_hci *hci, struct hci_xfer *xfer,
+			       u8 ccc_addr, u8 ccc_cmd, bool raw)
+{
+	unsigned int mode = XFERMODE_IDX_I3C_SDR;
+	unsigned int rate = get_i3c_rate_idx(hci);
+	u8 *data = xfer->data;
+	unsigned int data_len = xfer->data_len;
+	bool rnw = xfer->rnw;
+
+	if (raw && ccc_addr != I3C_BROADCAST_ADDR) {
+		hci_cmd_v2_prep_private_xfer(hci, xfer, ccc_addr, mode, rate);
+		return 0;
+	}
+
+	xfer->cmd_tid = hci_get_tid();
+
+	if (!rnw && data_len <= 4) {
+		xfer->cmd_desc[0] =
+			CMD_0_ATTR_U |
+			CMD_U0_TID(xfer->cmd_tid) |
+			CMD_U0_DEV_ADDRESS(ccc_addr) |
+			CMD_U0_XFER_RATE(rate) |
+			CMD_U0_MODE_INDEX(mode) |
+			CMD_U0_IDB_COUNT(data_len + (!raw ? 0 : 1));
+		xfer->cmd_desc[1] =
+			CMD_U1_DATA_LENGTH(0);
+		xfer->cmd_desc[2] =
+			CMD_U2_IDB0(ccc_cmd);
+		xfer->cmd_desc[3] = 0;
+		switch (data_len) {
+		case 4:
+			xfer->cmd_desc[3] |= CMD_U3_IDB4(data[3]);
+			fallthrough;
+		case 3:
+			xfer->cmd_desc[2] |= CMD_U2_IDB3(data[2]);
+			fallthrough;
+		case 2:
+			xfer->cmd_desc[2] |= CMD_U2_IDB2(data[1]);
+			fallthrough;
+		case 1:
+			xfer->cmd_desc[2] |= CMD_U2_IDB1(data[0]);
+			fallthrough;
+		case 0:
+			break;
+		}
+		/* we consumed all the data with the cmd descriptor */
+		xfer->data = NULL;
+	} else {
+		xfer->cmd_desc[0] =
+			CMD_0_ATTR_U |
+			CMD_U0_TID(xfer->cmd_tid) |
+			(rnw ? CMD_U0_RnW : 0) |
+			CMD_U0_DEV_ADDRESS(ccc_addr) |
+			CMD_U0_XFER_RATE(rate) |
+			CMD_U0_MODE_INDEX(mode) |
+			CMD_U0_IDB_COUNT(!raw ? 0 : 1);
+		xfer->cmd_desc[1] =
+			CMD_U1_DATA_LENGTH(data_len);
+		xfer->cmd_desc[2] =
+			CMD_U2_IDB0(ccc_cmd);
+		xfer->cmd_desc[3] = 0;
+	}
+
+	return 0;
+}
+
+static void hci_cmd_v2_prep_i3c_xfer(struct i3c_hci *hci,
+				     struct i3c_dev_desc *dev,
+				     struct hci_xfer *xfer)
+{
+	unsigned int mode = XFERMODE_IDX_I3C_SDR;
+	unsigned int rate = get_i3c_rate_idx(hci);
+	u8 addr = dev->info.dyn_addr;
+
+	hci_cmd_v2_prep_private_xfer(hci, xfer, addr, mode, rate);
+}
+
+static void hci_cmd_v2_prep_i2c_xfer(struct i3c_hci *hci,
+				     struct i2c_dev_desc *dev,
+				     struct hci_xfer *xfer)
+{
+	unsigned int mode = XFERMODE_IDX_I2C;
+	unsigned int rate = get_i2c_rate_idx(hci);
+	u8 addr = dev->addr;
+
+	hci_cmd_v2_prep_private_xfer(hci, xfer, addr, mode, rate);
+}
+
+static int hci_cmd_v2_daa(struct i3c_hci *hci)
+{
+	struct hci_xfer *xfer;
+	int ret;
+	u8 next_addr = 0;
+	u32 device_id[2];
+	u64 pid;
+	unsigned int dcr, bcr;
+	DECLARE_COMPLETION_ONSTACK(done);
+
+	xfer = hci_alloc_xfer(2);
+	if (!xfer)
+		return -ENOMEM;
+
+	xfer[0].data = &device_id;
+	xfer[0].data_len = 8;
+	xfer[0].rnw = true;
+	xfer[0].cmd_desc[1] = CMD_A1_DATA_LENGTH(8);
+	xfer[1].completion = &done;
+
+	for (;;) {
+		ret = i3c_master_get_free_addr(&hci->master, next_addr);
+		if (ret < 0)
+			break;
+		next_addr = ret;
+		DBG("next_addr = 0x%02x", next_addr);
+		xfer[0].cmd_tid = hci_get_tid();
+		xfer[0].cmd_desc[0] =
+			CMD_0_ATTR_A |
+			CMD_A0_TID(xfer[0].cmd_tid) |
+			CMD_A0_ROC;
+		xfer[1].cmd_tid = hci_get_tid();
+		xfer[1].cmd_desc[0] =
+			CMD_0_ATTR_A |
+			CMD_A0_TID(xfer[1].cmd_tid) |
+			CMD_A0_ASSIGN_ADDRESS(next_addr) |
+			CMD_A0_ROC |
+			CMD_A0_TOC;
+		hci->io->queue_xfer(hci, xfer, 2);
+		if (!wait_for_completion_timeout(&done, HZ) &&
+		    hci->io->dequeue_xfer(hci, xfer, 2)) {
+			ret = -ETIME;
+			break;
+		}
+		if (RESP_STATUS(xfer[0].response) != RESP_SUCCESS) {
+			ret = 0;  /* no more devices to be assigned */
+			break;
+		}
+		if (RESP_STATUS(xfer[1].response) != RESP_SUCCESS) {
+			ret = -EIO;
+			break;
+		}
+
+		pid = FIELD_GET(W1_MASK(47, 32), device_id[1]);
+		pid = (pid << 32) | device_id[0];
+		bcr = FIELD_GET(W1_MASK(55, 48), device_id[1]);
+		dcr = FIELD_GET(W1_MASK(63, 56), device_id[1]);
+		DBG("assigned address %#x to device PID=0x%llx DCR=%#x BCR=%#x",
+		    next_addr, pid, dcr, bcr);
+		/*
+		 * TODO: Extend the subsystem layer to allow for registering
+		 * new device and provide BCR/DCR/PID at the same time.
+		 */
+		ret = i3c_master_add_i3c_dev_locked(&hci->master, next_addr);
+		if (ret)
+			break;
+	}
+
+	hci_free_xfer(xfer, 2);
+	return ret;
+}
+
+const struct hci_cmd_ops mipi_i3c_hci_cmd_v2 = {
+	.prep_ccc		= hci_cmd_v2_prep_ccc,
+	.prep_i3c_xfer		= hci_cmd_v2_prep_i3c_xfer,
+	.prep_i2c_xfer		= hci_cmd_v2_prep_i2c_xfer,
+	.perform_daa		= hci_cmd_v2_daa,
+};