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, 184 insertions, 0 deletions

diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
new file mode 100644
index 000000000000..783e551a2c85
--- /dev/null
+++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Copyright (c) 2020, MIPI Alliance, Inc.
+ *
+ * Author: Nicolas Pitre <npitre@baylibre.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitmap.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/i3c/master.h>
+#include <linux/io.h>
+
+#include "hci.h"
+#include "dat.h"
+
+
+/*
+ * Device Address Table Structure
+ */
+
+#define DAT_1_AUTOCMD_HDR_CODE		W1_MASK(58, 51)
+#define DAT_1_AUTOCMD_MODE		W1_MASK(50, 48)
+#define DAT_1_AUTOCMD_VALUE		W1_MASK(47, 40)
+#define DAT_1_AUTOCMD_MASK		W1_MASK(39, 32)
+/*	DAT_0_I2C_DEVICE		W0_BIT_(31) */
+#define DAT_0_DEV_NACK_RETRY_CNT	W0_MASK(30, 29)
+#define DAT_0_RING_ID			W0_MASK(28, 26)
+#define DAT_0_DYNADDR_PARITY		W0_BIT_(23)
+#define DAT_0_DYNAMIC_ADDRESS		W0_MASK(22, 16)
+#define DAT_0_TS			W0_BIT_(15)
+#define DAT_0_MR_REJECT			W0_BIT_(14)
+/*	DAT_0_SIR_REJECT		W0_BIT_(13) */
+/*	DAT_0_IBI_PAYLOAD		W0_BIT_(12) */
+#define DAT_0_STATIC_ADDRESS		W0_MASK(6, 0)
+
+#define dat_w0_read(i)		readl(hci->DAT_regs + (i) * 8)
+#define dat_w1_read(i)		readl(hci->DAT_regs + (i) * 8 + 4)
+#define dat_w0_write(i, v)	writel(v, hci->DAT_regs + (i) * 8)
+#define dat_w1_write(i, v)	writel(v, hci->DAT_regs + (i) * 8 + 4)
+
+static inline bool dynaddr_parity(unsigned int addr)
+{
+	addr |= 1 << 7;
+	addr += addr >> 4;
+	addr += addr >> 2;
+	addr += addr >> 1;
+	return (addr & 1);
+}
+
+static int hci_dat_v1_init(struct i3c_hci *hci)
+{
+	unsigned int dat_idx;
+
+	if (!hci->DAT_regs) {
+		dev_err(&hci->master.dev,
+			"only DAT in register space is supported at the moment\n");
+		return -EOPNOTSUPP;
+	}
+	if (hci->DAT_entry_size != 8) {
+		dev_err(&hci->master.dev,
+			"only 8-bytes DAT entries are supported at the moment\n");
+		return -EOPNOTSUPP;
+	}
+
+	/* use a bitmap for faster free slot search */
+	hci->DAT_data = bitmap_zalloc(hci->DAT_entries, GFP_KERNEL);
+	if (!hci->DAT_data)
+		return -ENOMEM;
+
+	/* clear them */
+	for (dat_idx = 0; dat_idx < hci->DAT_entries; dat_idx++) {
+		dat_w0_write(dat_idx, 0);
+		dat_w1_write(dat_idx, 0);
+	}
+
+	return 0;
+}
+
+static void hci_dat_v1_cleanup(struct i3c_hci *hci)
+{
+	bitmap_free(hci->DAT_data);
+	hci->DAT_data = NULL;
+}
+
+static int hci_dat_v1_alloc_entry(struct i3c_hci *hci)
+{
+	unsigned int dat_idx;
+
+	dat_idx = find_first_zero_bit(hci->DAT_data, hci->DAT_entries);
+	if (dat_idx >= hci->DAT_entries)
+		return -ENOENT;
+	__set_bit(dat_idx, hci->DAT_data);
+
+	/* default flags */
+	dat_w0_write(dat_idx, DAT_0_SIR_REJECT | DAT_0_MR_REJECT);
+
+	return dat_idx;
+}
+
+static void hci_dat_v1_free_entry(struct i3c_hci *hci, unsigned int dat_idx)
+{
+	dat_w0_write(dat_idx, 0);
+	dat_w1_write(dat_idx, 0);
+	__clear_bit(dat_idx, hci->DAT_data);
+}
+
+static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,
+					unsigned int dat_idx, u8 address)
+{
+	u32 dat_w0;
+
+	dat_w0 = dat_w0_read(dat_idx);
+	dat_w0 &= ~(DAT_0_DYNAMIC_ADDRESS | DAT_0_DYNADDR_PARITY);
+	dat_w0 |= FIELD_PREP(DAT_0_DYNAMIC_ADDRESS, address) |
+		  (dynaddr_parity(address) ? DAT_0_DYNADDR_PARITY : 0);
+	dat_w0_write(dat_idx, dat_w0);
+}
+
+static void hci_dat_v1_set_static_addr(struct i3c_hci *hci,
+				       unsigned int dat_idx, u8 address)
+{
+	u32 dat_w0;
+
+	dat_w0 = dat_w0_read(dat_idx);
+	dat_w0 &= ~DAT_0_STATIC_ADDRESS;
+	dat_w0 |= FIELD_PREP(DAT_0_STATIC_ADDRESS, address);
+	dat_w0_write(dat_idx, dat_w0);
+}
+
+static void hci_dat_v1_set_flags(struct i3c_hci *hci, unsigned int dat_idx,
+				 u32 w0_flags, u32 w1_flags)
+{
+	u32 dat_w0, dat_w1;
+
+	dat_w0 = dat_w0_read(dat_idx);
+	dat_w1 = dat_w1_read(dat_idx);
+	dat_w0 |= w0_flags;
+	dat_w1 |= w1_flags;
+	dat_w0_write(dat_idx, dat_w0);
+	dat_w1_write(dat_idx, dat_w1);
+}
+
+static void hci_dat_v1_clear_flags(struct i3c_hci *hci, unsigned int dat_idx,
+				   u32 w0_flags, u32 w1_flags)
+{
+	u32 dat_w0, dat_w1;
+
+	dat_w0 = dat_w0_read(dat_idx);
+	dat_w1 = dat_w1_read(dat_idx);
+	dat_w0 &= ~w0_flags;
+	dat_w1 &= ~w1_flags;
+	dat_w0_write(dat_idx, dat_w0);
+	dat_w1_write(dat_idx, dat_w1);
+}
+
+static int hci_dat_v1_get_index(struct i3c_hci *hci, u8 dev_addr)
+{
+	unsigned int dat_idx;
+	u32 dat_w0;
+
+	for (dat_idx = find_first_bit(hci->DAT_data, hci->DAT_entries);
+	     dat_idx < hci->DAT_entries;
+	     dat_idx = find_next_bit(hci->DAT_data, hci->DAT_entries, dat_idx)) {
+		dat_w0 = dat_w0_read(dat_idx);
+		if (FIELD_GET(DAT_0_DYNAMIC_ADDRESS, dat_w0) == dev_addr)
+			return dat_idx;
+	}
+
+	return -ENODEV;
+}
+
+const struct hci_dat_ops mipi_i3c_hci_dat_v1 = {
+	.init			= hci_dat_v1_init,
+	.cleanup		= hci_dat_v1_cleanup,
+	.alloc_entry		= hci_dat_v1_alloc_entry,
+	.free_entry		= hci_dat_v1_free_entry,
+	.set_dynamic_addr	= hci_dat_v1_set_dynamic_addr,
+	.set_static_addr	= hci_dat_v1_set_static_addr,
+	.set_flags		= hci_dat_v1_set_flags,
+	.clear_flags		= hci_dat_v1_clear_flags,
+	.get_index		= hci_dat_v1_get_index,
+};