ch347_spi: Add initial support for the WCH CH347

Add support for the WCH CH347, a high-speed USB to bus converter
supporting multiple protocols interfaces including SPI. Currently only
mode 1 (vendor defined communication interface) is supported, mode 2
(USB HID communication interface) support will be added later. The code
is currently hard coded to use CS1 and a SPI clock of 15 MHz, though
there are 2 CS lines and 6 other GPIO lines available, as well as a
configurable clock divisor for up to 60MHz operation. Support for these
will be exposed through programmer parameters in later commits.

This currently uses the synchronous libusb API. Performance seems to be
alright so far, if it becomes an issue I may switch to the asynchronous
API.

Tested with a MX25L1606E flash chip

Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Change-Id: I31b86c41076cc45d4a416a73fa1131350fb745ba
Reviewed-on: https://review.coreboot.org/c/flashrom/+/70573
Reviewed-by: Thomas Heijligen <src@posteo.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 345 insertions, 0 deletions

diff --git a/ch347_spi.c b/ch347_spi.c
new file mode 100644
index 000000000..c3326b0c0
--- /dev/null
+++ b/ch347_spi.c
@@ -0,0 +1,345 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2022 Nicholas Chin <nic.c3.14@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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.
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <libusb.h>
+#include "platform.h"
+#include "programmer.h"
+#include "flash.h"
+
+#define CH347_CMD_SPI_SET_CFG	0xC0
+#define CH347_CMD_SPI_CS_CTRL	0xC1
+#define CH347_CMD_SPI_OUT_IN	0xC2
+#define CH347_CMD_SPI_IN	0xC3
+#define CH347_CMD_SPI_OUT	0xC4
+#define CH347_CMD_SPI_GET_CFG	0xCA
+
+#define CH347_CS_ASSERT		0x00
+#define CH347_CS_DEASSERT	0x40
+#define CH347_CS_CHANGE		0x80
+#define CH347_CS_IGNORE		0x00
+
+#define WRITE_EP	0x06
+#define READ_EP 	0x86
+
+#define MODE_1_IFACE 2
+#define MODE_2_IFACE 1
+
+/* The USB descriptor says the max transfer size is 512 bytes, but the
+ * vendor driver only seems to transfer a maximum of 510 bytes at once,
+ * leaving 507 bytes for data as the command + length take up 3 bytes
+ */
+#define CH347_PACKET_SIZE 510
+#define CH347_MAX_DATA_LEN (CH347_PACKET_SIZE - 3)
+
+struct ch347_spi_data {
+	struct libusb_device_handle *handle;
+};
+
+/* TODO: Add support for HID mode */
+static const struct dev_entry devs_ch347_spi[] = {
+	{0x1A86, 0x55DB, OK, "QinHeng Electronics", "USB To UART+SPI+I2C"},
+	{0}
+};
+
+static int ch347_spi_shutdown(void *data)
+{
+	struct ch347_spi_data *ch347_data = data;
+
+	/* TODO: Set this depending on the mode */
+	int spi_interface = MODE_1_IFACE;
+	libusb_release_interface(ch347_data->handle, spi_interface);
+	libusb_attach_kernel_driver(ch347_data->handle, spi_interface);
+	libusb_close(ch347_data->handle);
+	libusb_exit(NULL);
+
+	free(data);
+	return 0;
+}
+
+static int ch347_cs_control(struct ch347_spi_data *ch347_data, uint8_t cs1, uint8_t cs2)
+{
+	uint8_t cmd[13] = {
+		[0] = CH347_CMD_SPI_CS_CTRL,
+		/* payload length, uint16 LSB: 10 */
+		[1] = 10,
+		[3] = cs1,
+		[8] = cs2
+	};
+
+	int32_t ret = libusb_bulk_transfer(ch347_data->handle, WRITE_EP, cmd, sizeof(cmd), NULL, 1000);
+	if (ret < 0) {
+		msg_perr("Could not change CS!\n");
+		return -1;
+	}
+	return 0;
+}
+
+
+static int ch347_write(struct ch347_spi_data *ch347_data, unsigned int writecnt, const uint8_t *writearr)
+{
+	unsigned int data_len;
+	int packet_len;
+	int transferred;
+	int ret;
+	uint8_t resp_buf[4] = {0};
+	uint8_t buffer[CH347_PACKET_SIZE] = {0};
+	unsigned int bytes_written = 0;
+
+	while (bytes_written < writecnt) {
+		data_len = min(CH347_MAX_DATA_LEN, writecnt - bytes_written );
+		packet_len = data_len + 3;
+
+		buffer[0] = CH347_CMD_SPI_OUT;
+		buffer[1] = (data_len) & 0xFF;
+		buffer[2] = ((data_len) & 0xFF00) >> 8;
+		memcpy(buffer + 3, writearr + bytes_written, data_len);
+
+		ret = libusb_bulk_transfer(ch347_data->handle, WRITE_EP, buffer, packet_len, &transferred, 1000);
+		if (ret < 0 || transferred != packet_len) {
+			msg_perr("Could not send write command\n");
+			return -1;
+		}
+
+		ret = libusb_bulk_transfer(ch347_data->handle, READ_EP, resp_buf, sizeof(resp_buf), NULL, 1000);
+		if (ret < 0) {
+			msg_perr("Could not receive write command response\n");
+			return -1;
+		}
+		bytes_written += data_len;
+	}
+	return 0;
+}
+
+static int ch347_read(struct ch347_spi_data *ch347_data, unsigned int readcnt, uint8_t *readarr)
+{
+	uint8_t *read_ptr = readarr;
+	int ret;
+	int transferred;
+	unsigned int bytes_read = 0;
+	uint8_t buffer[CH347_PACKET_SIZE] = {0};
+	uint8_t command_buf[7] = {
+		[0] = CH347_CMD_SPI_IN,
+		[1] = 4,
+		[2] = 0,
+		[3] = readcnt & 0xFF,
+		[4] = (readcnt & 0xFF00) >> 8,
+		[5] = (readcnt & 0xFF0000) >> 16,
+		[6] = (readcnt & 0xFF000000) >> 24
+	};
+
+	ret = libusb_bulk_transfer(ch347_data->handle, WRITE_EP, command_buf, sizeof(command_buf), &transferred, 1000);
+	if (ret < 0 || transferred != sizeof(command_buf)) {
+		msg_perr("Could not send read command\n");
+		return -1;
+	}
+
+	while (bytes_read < readcnt) {
+		ret = libusb_bulk_transfer(ch347_data->handle, READ_EP, buffer, CH347_PACKET_SIZE, &transferred, 1000);
+		if (ret < 0) {
+			msg_perr("Could not read data\n");
+			return -1;
+		}
+		if (transferred > CH347_PACKET_SIZE) {
+			msg_perr("libusb bug: bytes received overflowed buffer\n");
+			return -1;
+		}
+		/* Response: u8 command, u16 data length, then the data that was read */
+		if (transferred < 3) {
+			msg_perr("CH347 returned an invalid response to read command\n");
+			return -1;
+		}
+		int ch347_data_length = read_le16(buffer, 1);
+		if (transferred - 3 < ch347_data_length) {
+			msg_perr("CH347 returned less data than data length header indicates\n");
+			return -1;
+		}
+		bytes_read += ch347_data_length;
+		if (bytes_read > readcnt) {
+			msg_perr("CH347 returned more bytes than requested\n");
+			return -1;
+		}
+		memcpy(read_ptr, buffer + 3, ch347_data_length);
+		read_ptr += ch347_data_length;
+	}
+	return 0;
+}
+
+static int ch347_spi_send_command(const struct flashctx *flash, unsigned int writecnt,
+		unsigned int readcnt, const unsigned char *writearr, unsigned char *readarr)
+{
+	struct ch347_spi_data *ch347_data = flash->mst->spi.data;
+	int ret = 0;
+
+	ch347_cs_control(ch347_data, CH347_CS_ASSERT | CH347_CS_CHANGE, CH347_CS_IGNORE);
+	if (writecnt) {
+		ret = ch347_write(ch347_data, writecnt, writearr);
+		if (ret < 0) {
+			msg_perr("CH347 write error\n");
+			return -1;
+		}
+	}
+	if (readcnt) {
+		ret = ch347_read(ch347_data, readcnt, readarr);
+		if (ret < 0) {
+			msg_perr("CH347 read error\n");
+			return -1;
+		}
+	}
+	ch347_cs_control(ch347_data, CH347_CS_DEASSERT | CH347_CS_CHANGE, CH347_CS_IGNORE);
+
+	return 0;
+}
+
+static int32_t ch347_spi_config(struct ch347_spi_data *ch347_data, uint8_t divisor)
+{
+	int32_t ret;
+	uint8_t buff[29] = {
+		[0] = CH347_CMD_SPI_SET_CFG,
+		[1] = (sizeof(buff) - 3) & 0xFF,
+		[2] = ((sizeof(buff) - 3) & 0xFF00) >> 8,
+		/* Not sure what these two bytes do, but the vendor
+		 * drivers seem to unconditionally set these values
+		 */
+		[5] = 4,
+		[6] = 1,
+		/* Clock polarity: bit 1 */
+		[9] = 0,
+		/* Clock phase: bit 0 */
+		[11] = 0,
+		/* Another mystery byte */
+		[14] = 2,
+		/* Clock divisor: bits 5:3 */
+		[15] = (divisor & 0x7) << 3,
+		/* Bit order: bit 7, 0=MSB */
+		[17] = 0,
+		/* Yet another mystery byte */
+		[19] = 7,
+		/* CS polarity: bit 7 CS2, bit 6 CS1. 0 = active low */
+		[24] = 0
+	};
+
+	ret = libusb_bulk_transfer(ch347_data->handle, WRITE_EP, buff, sizeof(buff), NULL, 1000);
+	if (ret < 0) {
+		msg_perr("Could not configure SPI interface\n");
+	}
+
+	/* FIXME: Not sure if the CH347 sends error responses for
+	 * invalid config data, if so the code should check
+	 */
+	ret = libusb_bulk_transfer(ch347_data->handle, READ_EP, buff, sizeof(buff), NULL, 1000);
+	if (ret < 0) {
+		msg_perr("Could not receive configure SPI command response\n");
+	}
+	return ret;
+}
+
+static const struct spi_master spi_master_ch347_spi = {
+	.features	= SPI_MASTER_4BA,
+	.max_data_read	= MAX_DATA_READ_UNLIMITED,
+	.max_data_write	= MAX_DATA_WRITE_UNLIMITED,
+	.command	= ch347_spi_send_command,
+	.multicommand	= default_spi_send_multicommand,
+	.read		= default_spi_read,
+	.write_256	= default_spi_write_256,
+	.write_aai	= default_spi_write_aai,
+	.shutdown	= ch347_spi_shutdown,
+	.probe_opcode	= default_spi_probe_opcode,
+};
+
+/* Largely copied from ch341a_spi.c */
+static int ch347_spi_init(const struct programmer_cfg *cfg)
+{
+	struct ch347_spi_data *ch347_data = calloc(1, sizeof(*ch347_data));
+	if (!ch347_data) {
+		msg_perr("Could not allocate space for SPI data\n");
+		return 1;
+	}
+
+	int32_t ret = libusb_init(NULL);
+	if (ret < 0) {
+		msg_perr("Could not initialize libusb!\n");
+		free(ch347_data);
+		return 1;
+	}
+
+	/* Enable information, warning, and error messages (only). */
+#if LIBUSB_API_VERSION < 0x01000106
+	libusb_set_debug(NULL, 3);
+#else
+	libusb_set_option(NULL, LIBUSB_OPTION_LOG_LEVEL, LIBUSB_LOG_LEVEL_INFO);
+#endif
+
+	uint16_t vid = devs_ch347_spi[0].vendor_id;
+	uint16_t pid = devs_ch347_spi[0].device_id;
+	ch347_data->handle = libusb_open_device_with_vid_pid(NULL, vid, pid);
+	if (ch347_data->handle == NULL) {
+		msg_perr("Couldn't open device %04x:%04x.\n", vid, pid);
+		free(ch347_data);
+		return 1;
+	}
+
+	/* TODO: set based on mode */
+	/* Mode 1 uses interface 2 for the SPI interface */
+	int spi_interface = MODE_1_IFACE;
+
+	ret = libusb_detach_kernel_driver(ch347_data->handle, spi_interface);
+	if (ret != 0 && ret != LIBUSB_ERROR_NOT_FOUND)
+		msg_pwarn("Cannot detach the existing USB driver. Claiming the interface may fail. %s\n",
+			libusb_error_name(ret));
+
+	ret = libusb_claim_interface(ch347_data->handle, spi_interface);
+	if (ret != 0) {
+		msg_perr("Failed to claim interface 2: '%s'\n", libusb_error_name(ret));
+		goto error_exit;
+	}
+
+	struct libusb_device *dev;
+	if (!(dev = libusb_get_device(ch347_data->handle))) {
+		msg_perr("Failed to get device from device handle.\n");
+		goto error_exit;
+	}
+
+	struct libusb_device_descriptor desc;
+	ret = libusb_get_device_descriptor(dev, &desc);
+	if (ret < 0) {
+		msg_perr("Failed to get device descriptor: '%s'\n", libusb_error_name(ret));
+		goto error_exit;
+	}
+
+	msg_pdbg("Device revision is %d.%01d.%01d\n",
+		(desc.bcdDevice >> 8) & 0x00FF,
+		(desc.bcdDevice >> 4) & 0x000F,
+		(desc.bcdDevice >> 0) & 0x000F);
+
+	/* TODO: add programmer cfg for things like CS pin and divisor */
+	if (ch347_spi_config(ch347_data, 2) < 0)
+		goto error_exit;
+
+	return register_spi_master(&spi_master_ch347_spi, ch347_data);
+
+error_exit:
+	ch347_spi_shutdown(ch347_data);
+	return 1;
+}
+
+const struct programmer_entry programmer_ch347_spi = {
+	.name		= "ch347_spi",
+	.type		= USB,
+	.devs.dev	= devs_ch347_spi,
+	.init		= ch347_spi_init,
+};