ASoC: codecs: Add NeoFidelity Firmware helpers

Add support for loading firmware for NeoFidelity amplifiers.

Signed-off-by: Igor Prusov <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Mark Brown <[e-mail]>

sound/soc/codecs/Kconfig

···
 	tristate
 	depends on I2C
 
+config SND_SOC_NTPFW
+	tristate
+
 config SND_SOC_TPA6130A2
 	tristate "Texas Instruments TPA6130A2 headphone amplifier"
 	depends on I2C

sound/soc/codecs/Makefile

···
 snd-soc-nau8822-y := nau8822.o
 snd-soc-nau8824-y := nau8824.o
 snd-soc-nau8825-y := nau8825.o
+snd-soc-ntpfw-y := ntpfw.o
 snd-soc-hdmi-codec-y := hdmi-codec.o
 snd-soc-pcm1681-y := pcm1681.o
 snd-soc-pcm1789-codec-y := pcm1789.o
···
 obj-$(CONFIG_SND_SOC_NAU8822)   += snd-soc-nau8822.o
 obj-$(CONFIG_SND_SOC_NAU8824)   += snd-soc-nau8824.o
 obj-$(CONFIG_SND_SOC_NAU8825)   += snd-soc-nau8825.o
+obj-$(CONFIG_SND_SOC_NTPFW)	+= snd-soc-ntpfw.o
 obj-$(CONFIG_SND_SOC_HDMI_CODEC)	+= snd-soc-hdmi-codec.o
 obj-$(CONFIG_SND_SOC_PCM1681)	+= snd-soc-pcm1681.o
 obj-$(CONFIG_SND_SOC_PCM179X)	+= snd-soc-pcm179x-codec.o

sound/soc/codecs/ntpfw.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ntpfw.c - Firmware helper functions for Neofidelity codecs
+ *
+ * Copyright (c) 2024, SaluteDevices. All Rights Reserved.
+ */
+
+#include <linux/i2c.h>
+#include <linux/firmware.h>
+#include <linux/module.h>
+
+#include "ntpfw.h"
+
+struct ntpfw_chunk {
+	__be16 length;
+	u8 step;
+	u8 data[];
+} __packed;
+
+struct ntpfw_header {
+	__be32 magic;
+} __packed;
+
+static bool ntpfw_verify(struct device *dev, const u8 *buf, size_t buf_size, u32 magic)
+{
+	const struct ntpfw_header *header = (struct ntpfw_header *)buf;
+	u32 buf_magic;
+
+	if (buf_size <= sizeof(*header)) {
+		dev_err(dev, "Failed to load firmware: image too small\n");
+		return false;
+	}
+
+	buf_magic = be32_to_cpu(header->magic);
+	if (buf_magic != magic) {
+		dev_err(dev, "Failed to load firmware: invalid magic 0x%x:\n", buf_magic);
+		return false;
+	}
+
+	return true;
+}
+
+static bool ntpfw_verify_chunk(struct device *dev, const struct ntpfw_chunk *chunk, size_t buf_size)
+{
+	size_t chunk_size;
+
+	if (buf_size <= sizeof(*chunk)) {
+		dev_err(dev, "Failed to load firmware: chunk size too big\n");
+		return false;
+	}
+
+	if (chunk->step != 2 && chunk->step != 5) {
+		dev_err(dev, "Failed to load firmware: invalid chunk step: %d\n", chunk->step);
+		return false;
+	}
+
+	chunk_size = be16_to_cpu(chunk->length);
+	if (chunk_size > buf_size) {
+		dev_err(dev, "Failed to load firmware: invalid chunk length\n");
+		return false;
+	}
+
+	if (chunk_size % chunk->step) {
+		dev_err(dev, "Failed to load firmware: chunk length and step mismatch\n");
+		return false;
+	}
+
+	return true;
+}
+
+static int ntpfw_send_chunk(struct i2c_client *i2c, const struct ntpfw_chunk *chunk)
+{
+	int ret;
+	size_t i;
+	size_t length = be16_to_cpu(chunk->length);
+
+	for (i = 0; i < length; i += chunk->step) {
+		ret = i2c_master_send(i2c, &chunk->data[i], chunk->step);
+		if (ret != chunk->step) {
+			dev_err(&i2c->dev, "I2C send failed: %d\n", ret);
+			return ret < 0 ? ret : -EIO;
+		}
+	}
+
+	return 0;
+}
+
+int ntpfw_load(struct i2c_client *i2c, const char *name, u32 magic)
+{
+	struct device *dev = &i2c->dev;
+	const struct ntpfw_chunk *chunk;
+	const struct firmware *fw;
+	const u8 *data;
+	size_t leftover;
+	int ret;
+
+	ret = request_firmware(&fw, name, dev);
+	if (ret) {
+		dev_warn(dev, "request_firmware '%s' failed with %d\n",
+			 name, ret);
+		return ret;
+	}
+
+	if (!ntpfw_verify(dev, fw->data, fw->size, magic)) {
+		ret = -EINVAL;
+		goto done;
+	}
+
+	data = fw->data + sizeof(struct ntpfw_header);
+	leftover = fw->size - sizeof(struct ntpfw_header);
+
+	while (leftover) {
+		chunk = (struct ntpfw_chunk *)data;
+
+		if (!ntpfw_verify_chunk(dev, chunk, leftover)) {
+			ret = -EINVAL;
+			goto done;
+		}
+
+		ret = ntpfw_send_chunk(i2c, chunk);
+		if (ret)
+			goto done;
+
+		data += be16_to_cpu(chunk->length) + sizeof(*chunk);
+		leftover -= be16_to_cpu(chunk->length) + sizeof(*chunk);
+	}
+
+done:
+	release_firmware(fw);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ntpfw_load);
+
+MODULE_AUTHOR("Igor Prusov <[e-mail]>");
+MODULE_DESCRIPTION("Helper for loading Neofidelity amplifiers firmware");
+MODULE_LICENSE("GPL");

sound/soc/codecs/ntpfw.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/**
+ * ntpfw.h - Firmware helper functions for Neofidelity codecs
+ *
+ * Copyright (c) 2024, SaluteDevices. All Rights Reserved.
+ */
+
+#ifndef __NTPFW_H__
+#define __NTPFW_H__
+#include <linux/i2c.h>
+#include <linux/firmware.h>
+
+/**
+ * ntpfw_load - load firmware to amplifier over i2c interface.
+ *
+ * @i2c		Pointer to amplifier's I2C client.
+ * @name	Firmware file name.
+ * @magic	Magic number to validate firmware.
+ * @return	0 or error code upon error.
+ */
+int ntpfw_load(struct i2c_client *i2c, const char *name, const u32 magic);
+
+#endif /* __NTPFW_H__ */