staging: wfx: load firmware

A firmware is necessary to run the chip. wfx_init_device() is in charge
of loading firmware on chip and doing low level initialization.

Firmwares for WF200 are available here:

https://github.com/SiliconLabs/wfx-firmware/

Note that firmware are encrypted. Driver checks that key used to encrypt
firmware match with key burned into chip.

Currently, "C0" key is used for production chips.

Signed-off-by: Jérôme Pouiller <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/wfx/Makefile

···
 
 wfx-y := \
 	hwio.o \
+	fwio.o \
 	main.o \
 	debug.o
 wfx-$(CONFIG_SPI) += bus_spi.o

drivers/staging/wfx/bus_sdio.c

···
 #include "main.h"
 
 static const struct wfx_platform_data wfx_sdio_pdata = {
+	.file_fw = "wfm_wf200",
 };
 
 struct wfx_sdio_priv {
···
 		goto err2;
 	}
 
+	ret = wfx_probe(bus->core);
+	if (ret)
+		goto err3;
+
 	return 0;
 
+err3:
+	wfx_free_common(bus->core);
 err2:
 	wfx_sdio_irq_unsubscribe(bus);
 err1:
···
 {
 	struct wfx_sdio_priv *bus = sdio_get_drvdata(func);
 
+	wfx_release(bus->core);
 	wfx_free_common(bus->core);
 	wfx_sdio_irq_unsubscribe(bus);
 	sdio_claim_host(func);

drivers/staging/wfx/bus_spi.c

···
 #define SET_READ 0x8000         /* usage: or operation */
 
 static const struct wfx_platform_data wfx_spi_pdata = {
+	.file_fw = "wfm_wf200",
+	.use_rising_clk = true,
 };
 
 struct wfx_spi_priv {
···
 	if (!bus->core)
 		return -EIO;
 
+	ret = wfx_probe(bus->core);
+	if (ret)
+		wfx_free_common(bus->core);
+
 	return ret;
 }
 
···
 {
 	struct wfx_spi_priv *bus = spi_get_drvdata(func);
 
+	wfx_release(bus->core);
 	wfx_free_common(bus->core);
 	// A few IRQ will be sent during device release. Hopefully, no IRQ
 	// should happen after wdev/wvif are released.

drivers/staging/wfx/fwio.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Firmware loading.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#include <linux/firmware.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/bitfield.h>
+
+#include "fwio.h"
+#include "wfx.h"
+#include "hwio.h"
+
+// Addresses below are in SRAM area
+#define WFX_DNLD_FIFO             0x09004000
+#define     DNLD_BLOCK_SIZE           0x0400
+#define     DNLD_FIFO_SIZE            0x8000 // (32 * DNLD_BLOCK_SIZE)
+// Download Control Area (DCA)
+#define WFX_DCA_IMAGE_SIZE        0x0900C000
+#define WFX_DCA_PUT               0x0900C004
+#define WFX_DCA_GET               0x0900C008
+#define WFX_DCA_HOST_STATUS       0x0900C00C
+#define     HOST_READY                0x87654321
+#define     HOST_INFO_READ            0xA753BD99
+#define     HOST_UPLOAD_PENDING       0xABCDDCBA
+#define     HOST_UPLOAD_COMPLETE      0xD4C64A99
+#define     HOST_OK_TO_JUMP           0x174FC882
+#define WFX_DCA_NCP_STATUS        0x0900C010
+#define     NCP_NOT_READY             0x12345678
+#define     NCP_READY                 0x87654321
+#define     NCP_INFO_READY            0xBD53EF99
+#define     NCP_DOWNLOAD_PENDING      0xABCDDCBA
+#define     NCP_DOWNLOAD_COMPLETE     0xCAFEFECA
+#define     NCP_AUTH_OK               0xD4C64A99
+#define     NCP_AUTH_FAIL             0x174FC882
+#define     NCP_PUB_KEY_RDY           0x7AB41D19
+#define WFX_DCA_FW_SIGNATURE      0x0900C014
+#define     FW_SIGNATURE_SIZE         0x40
+#define WFX_DCA_FW_HASH           0x0900C054
+#define     FW_HASH_SIZE              0x08
+#define WFX_DCA_FW_VERSION        0x0900C05C
+#define     FW_VERSION_SIZE           0x04
+#define WFX_DCA_RESERVED          0x0900C060
+#define     DCA_RESERVED_SIZE         0x20
+#define WFX_STATUS_INFO           0x0900C080
+#define WFX_BOOTLOADER_LABEL      0x0900C084
+#define     BOOTLOADER_LABEL_SIZE     0x3C
+#define WFX_PTE_INFO              0x0900C0C0
+#define     PTE_INFO_KEYSET_IDX       0x0D
+#define     PTE_INFO_SIZE             0x10
+#define WFX_ERR_INFO              0x0900C0D0
+#define     ERR_INVALID_SEC_TYPE      0x05
+#define     ERR_SIG_VERIF_FAILED      0x0F
+#define     ERR_AES_CTRL_KEY          0x10
+#define     ERR_ECC_PUB_KEY           0x11
+#define     ERR_MAC_KEY               0x18
+
+#define DCA_TIMEOUT  50 // milliseconds
+#define WAKEUP_TIMEOUT 200 // milliseconds
+
+static const char * const fwio_error_strings[] = {
+	[ERR_INVALID_SEC_TYPE] = "Invalid section type or wrong encryption",
+	[ERR_SIG_VERIF_FAILED] = "Signature verification failed",
+	[ERR_AES_CTRL_KEY] = "AES control key not initialized",
+	[ERR_ECC_PUB_KEY] = "ECC public key not initialized",
+	[ERR_MAC_KEY] = "MAC key not initialized",
+};
+
+/*
+ * request_firmware() allocate data using vmalloc(). It is not compatible with
+ * underlying hardware that use DMA. Function below detect this case and
+ * allocate a bounce buffer if necessary.
+ *
+ * Notice that, in doubt, you can enable CONFIG_DEBUG_SG to ask kernel to
+ * detect this problem at runtime  (else, kernel silently fail).
+ *
+ * NOTE: it may also be possible to use 'pages' from struct firmware and avoid
+ * bounce buffer
+ */
+int sram_write_dma_safe(struct wfx_dev *wdev, u32 addr, const u8 *buf, size_t len)
+{
+	int ret;
+	const u8 *tmp;
+
+	if (!virt_addr_valid(buf)) {
+		tmp = kmemdup(buf, len, GFP_KERNEL);
+		if (!tmp)
+			return -ENOMEM;
+	} else {
+		tmp = buf;
+	}
+	ret = sram_buf_write(wdev, addr, tmp, len);
+	if (!virt_addr_valid(buf))
+		kfree(tmp);
+	return ret;
+}
+
+int get_firmware(struct wfx_dev *wdev, u32 keyset_chip,
+		 const struct firmware **fw, int *file_offset)
+{
+	int keyset_file;
+	char filename[256];
+	const char *data;
+	int ret;
+
+	snprintf(filename, sizeof(filename), "%s_%02X.sec", wdev->pdata.file_fw, keyset_chip);
+	ret = firmware_request_nowarn(fw, filename, wdev->dev);
+	if (ret) {
+		dev_info(wdev->dev, "can't load %s, falling back to %s.sec\n", filename, wdev->pdata.file_fw);
+		snprintf(filename, sizeof(filename), "%s.sec", wdev->pdata.file_fw);
+		ret = request_firmware(fw, filename, wdev->dev);
+		if (ret) {
+			dev_err(wdev->dev, "can't load %s\n", filename);
+			*fw = NULL;
+			return ret;
+		}
+	}
+
+	data = (*fw)->data;
+	if (memcmp(data, "KEYSET", 6) != 0) {
+		// Legacy firmware format
+		*file_offset = 0;
+		keyset_file = 0x90;
+	} else {
+		*file_offset = 8;
+		keyset_file = (hex_to_bin(data[6]) * 16) | hex_to_bin(data[7]);
+		if (keyset_file < 0) {
+			dev_err(wdev->dev, "%s corrupted\n", filename);
+			release_firmware(*fw);
+			*fw = NULL;
+			return -EINVAL;
+		}
+	}
+	if (keyset_file != keyset_chip) {
+		dev_err(wdev->dev, "firmware keyset is incompatible with chip (file: 0x%02X, chip: 0x%02X)\n",
+			keyset_file, keyset_chip);
+		release_firmware(*fw);
+		*fw = NULL;
+		return -ENODEV;
+	}
+	wdev->keyset = keyset_file;
+	return 0;
+}
+
+static int wait_ncp_status(struct wfx_dev *wdev, u32 status)
+{
+	ktime_t now, start;
+	u32 reg;
+	int ret;
+
+	start = ktime_get();
+	for (;;) {
+		ret = sram_reg_read(wdev, WFX_DCA_NCP_STATUS, &reg);
+		if (ret < 0)
+			return -EIO;
+		now = ktime_get();
+		if (reg == status)
+			break;
+		if (ktime_after(now, ktime_add_ms(start, DCA_TIMEOUT)))
+			return -ETIMEDOUT;
+	}
+	if (ktime_compare(now, start))
+		dev_dbg(wdev->dev, "chip answer after %lldus\n", ktime_us_delta(now, start));
+	else
+		dev_dbg(wdev->dev, "chip answer immediately\n");
+	return 0;
+}
+
+static int upload_firmware(struct wfx_dev *wdev, const u8 *data, size_t len)
+{
+	int ret;
+	u32 offs, bytes_done;
+	ktime_t now, start;
+
+	if (len % DNLD_BLOCK_SIZE) {
+		dev_err(wdev->dev, "firmware size is not aligned. Buffer overrun will occur\n");
+		return -EIO;
+	}
+	offs = 0;
+	while (offs < len) {
+		start = ktime_get();
+		for (;;) {
+			ret = sram_reg_read(wdev, WFX_DCA_GET, &bytes_done);
+			if (ret < 0)
+				return ret;
+			now = ktime_get();
+			if (offs + DNLD_BLOCK_SIZE - bytes_done < DNLD_FIFO_SIZE)
+				break;
+			if (ktime_after(now, ktime_add_ms(start, DCA_TIMEOUT)))
+				return -ETIMEDOUT;
+		}
+		if (ktime_compare(now, start))
+			dev_dbg(wdev->dev, "answer after %lldus\n", ktime_us_delta(now, start));
+
+		ret = sram_write_dma_safe(wdev, WFX_DNLD_FIFO + (offs % DNLD_FIFO_SIZE),
+					  data + offs, DNLD_BLOCK_SIZE);
+		if (ret < 0)
+			return ret;
+
+		// WFx seems to not support writing 0 in this register during
+		// first loop
+		offs += DNLD_BLOCK_SIZE;
+		ret = sram_reg_write(wdev, WFX_DCA_PUT, offs);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
+static void print_boot_status(struct wfx_dev *wdev)
+{
+	u32 val32;
+
+	sram_reg_read(wdev, WFX_STATUS_INFO, &val32);
+	if (val32 == 0x12345678) {
+		dev_info(wdev->dev, "no error reported by secure boot\n");
+	} else {
+		sram_reg_read(wdev, WFX_ERR_INFO, &val32);
+		if (val32 < ARRAY_SIZE(fwio_error_strings) && fwio_error_strings[val32])
+			dev_info(wdev->dev, "secure boot error: %s\n", fwio_error_strings[val32]);
+		else
+			dev_info(wdev->dev, "secure boot error: Unknown (0x%02x)\n", val32);
+	}
+}
+
+int load_firmware_secure(struct wfx_dev *wdev)
+{
+	const struct firmware *fw = NULL;
+	int header_size;
+	int fw_offset;
+	ktime_t start;
+	u8 *buf;
+	int ret;
+
+	BUILD_BUG_ON(PTE_INFO_SIZE > BOOTLOADER_LABEL_SIZE);
+	buf = kmalloc(BOOTLOADER_LABEL_SIZE + 1, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	sram_reg_write(wdev, WFX_DCA_HOST_STATUS, HOST_READY);
+	ret = wait_ncp_status(wdev, NCP_INFO_READY);
+	if (ret)
+		goto error;
+
+	sram_buf_read(wdev, WFX_BOOTLOADER_LABEL, buf, BOOTLOADER_LABEL_SIZE);
+	buf[BOOTLOADER_LABEL_SIZE] = 0;
+	dev_dbg(wdev->dev, "bootloader: \"%s\"\n", buf);
+
+	sram_buf_read(wdev, WFX_PTE_INFO, buf, PTE_INFO_SIZE);
+	ret = get_firmware(wdev, buf[PTE_INFO_KEYSET_IDX], &fw, &fw_offset);
+	if (ret)
+		goto error;
+	header_size = fw_offset + FW_SIGNATURE_SIZE + FW_HASH_SIZE;
+
+	sram_reg_write(wdev, WFX_DCA_HOST_STATUS, HOST_INFO_READ);
+	ret = wait_ncp_status(wdev, NCP_READY);
+	if (ret)
+		goto error;
+
+	sram_reg_write(wdev, WFX_DNLD_FIFO, 0xFFFFFFFF); // Fifo init
+	sram_write_dma_safe(wdev, WFX_DCA_FW_VERSION, "\x01\x00\x00\x00", FW_VERSION_SIZE);
+	sram_write_dma_safe(wdev, WFX_DCA_FW_SIGNATURE, fw->data + fw_offset, FW_SIGNATURE_SIZE);
+	sram_write_dma_safe(wdev, WFX_DCA_FW_HASH, fw->data + fw_offset + FW_SIGNATURE_SIZE, FW_HASH_SIZE);
+	sram_reg_write(wdev, WFX_DCA_IMAGE_SIZE, fw->size - header_size);
+	sram_reg_write(wdev, WFX_DCA_HOST_STATUS, HOST_UPLOAD_PENDING);
+	ret = wait_ncp_status(wdev, NCP_DOWNLOAD_PENDING);
+	if (ret)
+		goto error;
+
+	start = ktime_get();
+	ret = upload_firmware(wdev, fw->data + header_size, fw->size - header_size);
+	if (ret)
+		goto error;
+	dev_dbg(wdev->dev, "firmware load after %lldus\n", ktime_us_delta(ktime_get(), start));
+
+	sram_reg_write(wdev, WFX_DCA_HOST_STATUS, HOST_UPLOAD_COMPLETE);
+	ret = wait_ncp_status(wdev, NCP_AUTH_OK);
+	// Legacy ROM support
+	if (ret < 0)
+		ret = wait_ncp_status(wdev, NCP_PUB_KEY_RDY);
+	if (ret < 0)
+		goto error;
+	sram_reg_write(wdev, WFX_DCA_HOST_STATUS, HOST_OK_TO_JUMP);
+
+error:
+	kfree(buf);
+	if (fw)
+		release_firmware(fw);
+	if (ret)
+		print_boot_status(wdev);
+	return ret;
+}
+
+static int init_gpr(struct wfx_dev *wdev)
+{
+	int ret, i;
+	static const struct {
+		int index;
+		u32 value;
+	} gpr_init[] = {
+		{ 0x07, 0x208775 },
+		{ 0x08, 0x2EC020 },
+		{ 0x09, 0x3C3C3C },
+		{ 0x0B, 0x322C44 },
+		{ 0x0C, 0xA06497 },
+	};
+
+	for (i = 0; i < ARRAY_SIZE(gpr_init); i++) {
+		ret = igpr_reg_write(wdev, gpr_init[i].index, gpr_init[i].value);
+		if (ret < 0)
+			return ret;
+		dev_dbg(wdev->dev, "  index %02x: %08x\n", gpr_init[i].index, gpr_init[i].value);
+	}
+	return 0;
+}
+
+int wfx_init_device(struct wfx_dev *wdev)
+{
+	int ret;
+	int hw_revision, hw_type;
+	int wakeup_timeout = 50; // ms
+	ktime_t now, start;
+	u32 reg;
+
+	reg = CFG_DIRECT_ACCESS_MODE | CFG_CPU_RESET | CFG_WORD_MODE2;
+	if (wdev->pdata.use_rising_clk)
+		reg |= CFG_CLK_RISE_EDGE;
+	ret = config_reg_write(wdev, reg);
+	if (ret < 0) {
+		dev_err(wdev->dev, "bus returned an error during first write access. Host configuration error?\n");
+		return -EIO;
+	}
+
+	ret = config_reg_read(wdev, &reg);
+	if (ret < 0) {
+		dev_err(wdev->dev, "bus returned an error during first read access. Bus configuration error?\n");
+		return -EIO;
+	}
+	if (reg == 0 || reg == ~0) {
+		dev_err(wdev->dev, "chip mute. Bus configuration error or chip wasn't reset?\n");
+		return -EIO;
+	}
+	dev_dbg(wdev->dev, "initial config register value: %08x\n", reg);
+
+	hw_revision = FIELD_GET(CFG_DEVICE_ID_MAJOR, reg);
+	if (hw_revision == 0 || hw_revision > 2) {
+		dev_err(wdev->dev, "bad hardware revision number: %d\n", hw_revision);
+		return -ENODEV;
+	}
+	hw_type = FIELD_GET(CFG_DEVICE_ID_TYPE, reg);
+	if (hw_type == 1) {
+		dev_notice(wdev->dev, "development hardware detected\n");
+		wakeup_timeout = 2000;
+	}
+
+	ret = init_gpr(wdev);
+	if (ret < 0)
+		return ret;
+
+	ret = control_reg_write(wdev, CTRL_WLAN_WAKEUP);
+	if (ret < 0)
+		return -EIO;
+	start = ktime_get();
+	for (;;) {
+		ret = control_reg_read(wdev, &reg);
+		now = ktime_get();
+		if (reg & CTRL_WLAN_READY)
+			break;
+		if (ktime_after(now, ktime_add_ms(start, wakeup_timeout))) {
+			dev_err(wdev->dev, "chip didn't wake up. Chip wasn't reset?\n");
+			return -ETIMEDOUT;
+		}
+	}
+	dev_dbg(wdev->dev, "chip wake up after %lldus\n", ktime_us_delta(now, start));
+
+	ret = config_reg_write_bits(wdev, CFG_CPU_RESET, 0);
+	if (ret < 0)
+		return ret;
+	ret = load_firmware_secure(wdev);
+	if (ret < 0)
+		return ret;
+	ret = config_reg_write_bits(wdev, CFG_DIRECT_ACCESS_MODE | CFG_IRQ_ENABLE_DATA | CFG_IRQ_ENABLE_WRDY, CFG_IRQ_ENABLE_DATA);
+	return ret;
+}

drivers/staging/wfx/fwio.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Firmware loading.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#ifndef WFX_FWIO_H
+#define WFX_FWIO_H
+
+struct wfx_dev;
+
+int wfx_init_device(struct wfx_dev *wdev);
+
+#endif /* WFX_FWIO_H */

drivers/staging/wfx/main.c

···
 
 #include "main.h"
 #include "wfx.h"
+#include "fwio.h"
+#include "hwio.h"
 #include "bus.h"
 #include "wfx_version.h"
 
···
 }
 
 void wfx_free_common(struct wfx_dev *wdev)
+{
+}
+
+int wfx_probe(struct wfx_dev *wdev)
+{
+	int err;
+
+	err = wfx_init_device(wdev);
+	if (err)
+		goto err1;
+
+	return 0;
+
+err1:
+	return err;
+}
+
+void wfx_release(struct wfx_dev *wdev)
 {
 }
 

drivers/staging/wfx/main.h

···
 struct wfx_dev;
 
 struct wfx_platform_data {
+	/* Keyset and ".sec" extention will appended to this string */
+	const char *file_fw;
+	/*
+	 * if true HIF D_out is sampled on the rising edge of the clock
+	 * (intended to be used in 50Mhz SDIO)
+	 */
+	bool use_rising_clk;
 };
 
 struct wfx_dev *wfx_init_common(struct device *dev,
···
 				const struct hwbus_ops *hwbus_ops,
 				void *hwbus_priv);
 void wfx_free_common(struct wfx_dev *wdev);
+
+int wfx_probe(struct wfx_dev *wdev);
+void wfx_release(struct wfx_dev *wdev);
 
 struct gpio_desc *wfx_get_gpio(struct device *dev, int override,
 			       const char *label);

drivers/staging/wfx/wfx.h

···
 	struct device		*dev;
 	const struct hwbus_ops	*hwbus_ops;
 	void			*hwbus_priv;
+
+	u8			keyset;
 };
 
 #endif /* WFX_H */