staging: wfx: add support for I/O access

Introduce bus level communication layer. At this level, 7 registers can
be addressed.

Notice that SPI driver is able to manage chip reset. SDIO mode relies
on an external driver (`mmc-pwrseq`) to reset chip.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20190919142527.31797-3-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/bus.h

@@ -11,6 +11,23 @@
 #include <linux/mmc/sdio_func.h>
 #include <linux/spi/spi.h>
 
+#define WFX_REG_CONFIG        0x0
+#define WFX_REG_CONTROL       0x1
+#define WFX_REG_IN_OUT_QUEUE  0x2
+#define WFX_REG_AHB_DPORT     0x3
+#define WFX_REG_BASE_ADDR     0x4
+#define WFX_REG_SRAM_DPORT    0x5
+#define WFX_REG_SET_GEN_R_W   0x6
+#define WFX_REG_FRAME_OUT     0x7
+
+struct hwbus_ops {
+	int (*copy_from_io)(void *bus_priv, unsigned int addr, void *dst, size_t count);
+	int (*copy_to_io)(void *bus_priv, unsigned int addr, const void *src, size_t count);
+	void (*lock)(void *bus_priv);
+	void (*unlock)(void *bus_priv);
+	size_t (*align_size)(void *bus_priv, size_t size);
+};
+
 extern struct sdio_driver wfx_sdio_driver;
 extern struct spi_driver wfx_spi_driver;
 

drivers/staging/wfx/bus_sdio.c

@@ -8,36 +8,223 @@
 #include <linux/module.h>
 #include <linux/mmc/sdio_func.h>
 #include <linux/mmc/card.h>
+#include <linux/interrupt.h>
 #include <linux/of_irq.h>
 
 #include "bus.h"
+#include "wfx.h"
+#include "hwio.h"
+#include "main.h"
+
+static const struct wfx_platform_data wfx_sdio_pdata = {
+};
+
+struct wfx_sdio_priv {
+	struct sdio_func *func;
+	struct wfx_dev *core;
+	u8 buf_id_tx;
+	u8 buf_id_rx;
+	int of_irq;
+};
+
+static int wfx_sdio_copy_from_io(void *priv, unsigned int reg_id,
+				 void *dst, size_t count)
+{
+	struct wfx_sdio_priv *bus = priv;
+	unsigned int sdio_addr = reg_id << 2;
+	int ret;
+
+	BUG_ON(reg_id > 7);
+	WARN(((uintptr_t) dst) & 3, "unaligned buffer size");
+	WARN(count & 3, "unaligned buffer address");
+
+	/* Use queue mode buffers */
+	if (reg_id == WFX_REG_IN_OUT_QUEUE)
+		sdio_addr |= (bus->buf_id_rx + 1) << 7;
+	ret = sdio_memcpy_fromio(bus->func, dst, sdio_addr, count);
+	if (!ret && reg_id == WFX_REG_IN_OUT_QUEUE)
+		bus->buf_id_rx = (bus->buf_id_rx + 1) % 4;
+
+	return ret;
+}
+
+static int wfx_sdio_copy_to_io(void *priv, unsigned int reg_id,
+			       const void *src, size_t count)
+{
+	struct wfx_sdio_priv *bus = priv;
+	unsigned int sdio_addr = reg_id << 2;
+	int ret;
+
+	BUG_ON(reg_id > 7);
+	WARN(((uintptr_t) src) & 3, "unaligned buffer size");
+	WARN(count & 3, "unaligned buffer address");
+
+	/* Use queue mode buffers */
+	if (reg_id == WFX_REG_IN_OUT_QUEUE)
+		sdio_addr |= bus->buf_id_tx << 7;
+	// FIXME: discards 'const' qualifier for src
+	ret = sdio_memcpy_toio(bus->func, sdio_addr, (void *) src, count);
+	if (!ret && reg_id == WFX_REG_IN_OUT_QUEUE)
+		bus->buf_id_tx = (bus->buf_id_tx + 1) % 32;
+
+	return ret;
+}
+
+static void wfx_sdio_lock(void *priv)
+{
+	struct wfx_sdio_priv *bus = priv;
+
+	sdio_claim_host(bus->func);
+}
+
+static void wfx_sdio_unlock(void *priv)
+{
+	struct wfx_sdio_priv *bus = priv;
+
+	sdio_release_host(bus->func);
+}
+
+static void wfx_sdio_irq_handler(struct sdio_func *func)
+{
+	struct wfx_sdio_priv *bus = sdio_get_drvdata(func);
+
+	if (bus->core)
+		/* empty */;
+	else
+		WARN(!bus->core, "race condition in driver init/deinit");
+}
+
+static irqreturn_t wfx_sdio_irq_handler_ext(int irq, void *priv)
+{
+	struct wfx_sdio_priv *bus = priv;
+
+	if (!bus->core) {
+		WARN(!bus->core, "race condition in driver init/deinit");
+		return IRQ_NONE;
+	}
+	sdio_claim_host(bus->func);
+	sdio_release_host(bus->func);
+	return IRQ_HANDLED;
+}
+
+static int wfx_sdio_irq_subscribe(struct wfx_sdio_priv *bus)
+{
+	int ret;
+
+	if (bus->of_irq) {
+		ret = request_irq(bus->of_irq, wfx_sdio_irq_handler_ext,
+				  IRQF_TRIGGER_RISING, "wfx", bus);
+	} else {
+		sdio_claim_host(bus->func);
+		ret = sdio_claim_irq(bus->func, wfx_sdio_irq_handler);
+		sdio_release_host(bus->func);
+	}
+	return ret;
+}
+
+static int wfx_sdio_irq_unsubscribe(struct wfx_sdio_priv *bus)
+{
+	int ret;
+
+	if (bus->of_irq) {
+		free_irq(bus->of_irq, bus);
+		ret = 0;
+	} else {
+		sdio_claim_host(bus->func);
+		ret = sdio_release_irq(bus->func);
+		sdio_release_host(bus->func);
+	}
+	return ret;
+}
+
+static size_t wfx_sdio_align_size(void *priv, size_t size)
+{
+	struct wfx_sdio_priv *bus = priv;
+
+	return sdio_align_size(bus->func, size);
+}
+
+static const struct hwbus_ops wfx_sdio_hwbus_ops = {
+	.copy_from_io = wfx_sdio_copy_from_io,
+	.copy_to_io = wfx_sdio_copy_to_io,
+	.lock			= wfx_sdio_lock,
+	.unlock			= wfx_sdio_unlock,
+	.align_size		= wfx_sdio_align_size,
+};
 
 static const struct of_device_id wfx_sdio_of_match[];
 static int wfx_sdio_probe(struct sdio_func *func,
 			  const struct sdio_device_id *id)
 {
 	struct device_node *np = func->dev.of_node;
+	struct wfx_sdio_priv *bus;
+	int ret;
 
 	if (func->num != 1) {
 		dev_err(&func->dev, "SDIO function number is %d while it should always be 1 (unsupported chip?)\n", func->num);
 		return -ENODEV;
 	}
 
+	bus = devm_kzalloc(&func->dev, sizeof(*bus), GFP_KERNEL);
+	if (!bus)
+		return -ENOMEM;
+
 	if (np) {
 		if (!of_match_node(wfx_sdio_of_match, np)) {
 			dev_warn(&func->dev, "no compatible device found in DT\n");
 			return -ENODEV;
 		}
+		bus->of_irq = irq_of_parse_and_map(np, 0);
 	} else {
 		dev_warn(&func->dev, "device is not declared in DT, features will be limited\n");
 		// FIXME: ignore VID/PID and only rely on device tree
 		// return -ENODEV;
 	}
-	return -EIO; // FIXME: not yet supported
+
+	bus->func = func;
+	sdio_set_drvdata(func, bus);
+	func->card->quirks |= MMC_QUIRK_LENIENT_FN0 | MMC_QUIRK_BLKSZ_FOR_BYTE_MODE | MMC_QUIRK_BROKEN_BYTE_MODE_512;
+
+	sdio_claim_host(func);
+	ret = sdio_enable_func(func);
+	// Block of 64 bytes is more efficient than 512B for frame sizes < 4k
+	sdio_set_block_size(func, 64);
+	sdio_release_host(func);
+	if (ret)
+		goto err0;
+
+	ret = wfx_sdio_irq_subscribe(bus);
+	if (ret)
+		goto err1;
+
+	bus->core = wfx_init_common(&func->dev, &wfx_sdio_pdata,
+				    &wfx_sdio_hwbus_ops, bus);
+	if (!bus->core) {
+		ret = -EIO;
+		goto err2;
+	}
+
+	return 0;
+
+err2:
+	wfx_sdio_irq_unsubscribe(bus);
+err1:
+	sdio_claim_host(func);
+	sdio_disable_func(func);
+	sdio_release_host(func);
+err0:
+	return ret;
 }
 
 static void wfx_sdio_remove(struct sdio_func *func)
 {
+	struct wfx_sdio_priv *bus = sdio_get_drvdata(func);
+
+	wfx_free_common(bus->core);
+	wfx_sdio_irq_unsubscribe(bus);
+	sdio_claim_host(func);
+	sdio_disable_func(func);
+	sdio_release_host(func);
 }
 
 #define SDIO_VENDOR_ID_SILABS        0x0000

drivers/staging/wfx/bus_spi.c

@@ -7,19 +7,217 @@
  * Copyright (c) 2010, ST-Ericsson
  */
 #include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/spi/spi.h>
+#include <linux/interrupt.h>
 #include <linux/of.h>
 
 #include "bus.h"
+#include "wfx.h"
+#include "hwio.h"
+#include "main.h"
+
+static int gpio_reset = -2;
+module_param(gpio_reset, int, 0644);
+MODULE_PARM_DESC(gpio_reset, "gpio number for reset. -1 for none.");
+
+#define SET_WRITE 0x7FFF        /* usage: and operation */
+#define SET_READ 0x8000         /* usage: or operation */
+
+static const struct wfx_platform_data wfx_spi_pdata = {
+};
+
+struct wfx_spi_priv {
+	struct spi_device *func;
+	struct wfx_dev *core;
+	struct gpio_desc *gpio_reset;
+	struct work_struct request_rx;
+	bool need_swab;
+};
+
+/*
+ * WFx chip read data 16bits at time and place them directly into (little
+ * endian) CPU register. So, chip expect byte order like "B1 B0 B3 B2" (while
+ * LE is "B0 B1 B2 B3" and BE is "B3 B2 B1 B0")
+ *
+ * A little endian host with bits_per_word == 16 should do the right job
+ * natively. The code below to support big endian host and commonly used SPI
+ * 8bits.
+ */
+static int wfx_spi_copy_from_io(void *priv, unsigned int addr,
+				void *dst, size_t count)
+{
+	struct wfx_spi_priv *bus = priv;
+	u16 regaddr = (addr << 12) | (count / 2) | SET_READ;
+	struct spi_message      m;
+	struct spi_transfer     t_addr = {
+		.tx_buf         = &regaddr,
+		.len            = sizeof(regaddr),
+	};
+	struct spi_transfer     t_msg = {
+		.rx_buf         = dst,
+		.len            = count,
+	};
+	u16 *dst16 = dst;
+	int ret, i;
+
+	WARN(count % 2, "buffer size must be a multiple of 2");
+
+	cpu_to_le16s(&regaddr);
+	if (bus->need_swab)
+		swab16s(&regaddr);
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t_addr, &m);
+	spi_message_add_tail(&t_msg, &m);
+	ret = spi_sync(bus->func, &m);
+
+	if (bus->need_swab && addr == WFX_REG_CONFIG)
+		for (i = 0; i < count / 2; i++)
+			swab16s(&dst16[i]);
+	return ret;
+}
+
+static int wfx_spi_copy_to_io(void *priv, unsigned int addr,
+			      const void *src, size_t count)
+{
+	struct wfx_spi_priv *bus = priv;
+	u16 regaddr = (addr << 12) | (count / 2);
+	// FIXME: use a bounce buffer
+	u16 *src16 = (void *) src;
+	int ret, i;
+	struct spi_message      m;
+	struct spi_transfer     t_addr = {
+		.tx_buf         = &regaddr,
+		.len            = sizeof(regaddr),
+	};
+	struct spi_transfer     t_msg = {
+		.tx_buf         = src,
+		.len            = count,
+	};
+
+	WARN(count % 2, "buffer size must be a multiple of 2");
+	WARN(regaddr & SET_READ, "bad addr or size overflow");
+
+	cpu_to_le16s(&regaddr);
+
+	if (bus->need_swab)
+		swab16s(&regaddr);
+	if (bus->need_swab && addr == WFX_REG_CONFIG)
+		for (i = 0; i < count / 2; i++)
+			swab16s(&src16[i]);
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t_addr, &m);
+	spi_message_add_tail(&t_msg, &m);
+	ret = spi_sync(bus->func, &m);
+
+	if (bus->need_swab && addr == WFX_REG_CONFIG)
+		for (i = 0; i < count / 2; i++)
+			swab16s(&src16[i]);
+	return ret;
+}
+
+static void wfx_spi_lock(void *priv)
+{
+}
+
+static void wfx_spi_unlock(void *priv)
+{
+}
+
+static irqreturn_t wfx_spi_irq_handler(int irq, void *priv)
+{
+	struct wfx_spi_priv *bus = priv;
+
+	if (!bus->core) {
+		WARN(!bus->core, "race condition in driver init/deinit");
+		return IRQ_NONE;
+	}
+	queue_work(system_highpri_wq, &bus->request_rx);
+	return IRQ_HANDLED;
+}
+
+static void wfx_spi_request_rx(struct work_struct *work)
+{
+}
+
+static size_t wfx_spi_align_size(void *priv, size_t size)
+{
+	// Most of SPI controllers avoid DMA if buffer size is not 32bit aligned
+	return ALIGN(size, 4);
+}
+
+static const struct hwbus_ops wfx_spi_hwbus_ops = {
+	.copy_from_io = wfx_spi_copy_from_io,
+	.copy_to_io = wfx_spi_copy_to_io,
+	.lock			= wfx_spi_lock,
+	.unlock			= wfx_spi_unlock,
+	.align_size		= wfx_spi_align_size,
+};
 
 static int wfx_spi_probe(struct spi_device *func)
 {
-	return -EIO;
+	struct wfx_spi_priv *bus;
+	int ret;
+
+	if (!func->bits_per_word)
+		func->bits_per_word = 16;
+	ret = spi_setup(func);
+	if (ret)
+		return ret;
+	// Trace below is also displayed by spi_setup() if compiled with DEBUG
+	dev_dbg(&func->dev, "SPI params: CS=%d, mode=%d bits/word=%d speed=%d\n",
+		func->chip_select, func->mode, func->bits_per_word, func->max_speed_hz);
+	if (func->bits_per_word != 16 && func->bits_per_word != 8)
+		dev_warn(&func->dev, "unusual bits/word value: %d\n", func->bits_per_word);
+	if (func->max_speed_hz > 49000000)
+		dev_warn(&func->dev, "%dHz is a very high speed\n", func->max_speed_hz);
+
+	bus = devm_kzalloc(&func->dev, sizeof(*bus), GFP_KERNEL);
+	if (!bus)
+		return -ENOMEM;
+	bus->func = func;
+	if (func->bits_per_word == 8 || IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
+		bus->need_swab = true;
+	spi_set_drvdata(func, bus);
+
+	bus->gpio_reset = wfx_get_gpio(&func->dev, gpio_reset, "reset");
+	if (!bus->gpio_reset) {
+		dev_warn(&func->dev, "try to load firmware anyway\n");
+	} else {
+		gpiod_set_value(bus->gpio_reset, 0);
+		udelay(100);
+		gpiod_set_value(bus->gpio_reset, 1);
+		udelay(2000);
+	}
+
+	ret = devm_request_irq(&func->dev, func->irq, wfx_spi_irq_handler,
+			       IRQF_TRIGGER_RISING, "wfx", bus);
+	if (ret)
+		return ret;
+
+	INIT_WORK(&bus->request_rx, wfx_spi_request_rx);
+	bus->core = wfx_init_common(&func->dev, &wfx_spi_pdata,
+				    &wfx_spi_hwbus_ops, bus);
+	if (!bus->core)
+		return -EIO;
+
+	return ret;
 }
 
 /* Disconnect Function to be called by SPI stack when device is disconnected */
 static int wfx_spi_disconnect(struct spi_device *func)
 {
+	struct wfx_spi_priv *bus = spi_get_drvdata(func);
+
+	wfx_free_common(bus->core);
+	// A few IRQ will be sent during device release. Hopefully, no IRQ
+	// should happen after wdev/wvif are released.
+	devm_free_irq(&func->dev, func->irq, bus);
+	flush_work(&bus->request_rx);
 	return 0;
 }
 

drivers/staging/wfx/hwio.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Low-level API.
+ *
+ * Copyright (c) 2017-2018, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#ifndef WFX_HWIO_H
+#define WFX_HWIO_H
+
+#define CFG_ERR_SPI_FRAME          0x00000001 // only with SPI
+#define CFG_ERR_SDIO_BUF_MISMATCH  0x00000001 // only with SDIO
+#define CFG_ERR_BUF_UNDERRUN       0x00000002
+#define CFG_ERR_DATA_IN_TOO_LARGE  0x00000004
+#define CFG_ERR_HOST_NO_OUT_QUEUE  0x00000008
+#define CFG_ERR_BUF_OVERRUN        0x00000010
+#define CFG_ERR_DATA_OUT_TOO_LARGE 0x00000020
+#define CFG_ERR_HOST_NO_IN_QUEUE   0x00000040
+#define CFG_ERR_HOST_CRC_MISS      0x00000080 // only with SDIO
+#define CFG_SPI_IGNORE_CS          0x00000080 // only with SPI
+#define CFG_WORD_MODE_MASK         0x00000300 // Bytes ordering (only writable in SPI):
+#define     CFG_WORD_MODE0         0x00000000 //   B1,B0,B3,B2 (In SPI, register address and CONFIG data always use this mode)
+#define     CFG_WORD_MODE1         0x00000100 //   B3,B2,B1,B0
+#define     CFG_WORD_MODE2         0x00000200 //   B0,B1,B2,B3 (SDIO)
+#define CFG_DIRECT_ACCESS_MODE     0x00000400 // Direct or queue access mode
+#define CFG_PREFETCH_AHB           0x00000800
+#define CFG_DISABLE_CPU_CLK        0x00001000
+#define CFG_PREFETCH_SRAM          0x00002000
+#define CFG_CPU_RESET              0x00004000
+#define CFG_SDIO_DISABLE_IRQ       0x00008000 // only with SDIO
+#define CFG_IRQ_ENABLE_DATA        0x00010000
+#define CFG_IRQ_ENABLE_WRDY        0x00020000
+#define CFG_CLK_RISE_EDGE          0x00040000
+#define CFG_SDIO_DISABLE_CRC_CHK   0x00080000 // only with SDIO
+#define CFG_RESERVED               0x00F00000
+#define CFG_DEVICE_ID_MAJOR        0x07000000
+#define CFG_DEVICE_ID_RESERVED     0x78000000
+#define CFG_DEVICE_ID_TYPE         0x80000000
+
+#define CTRL_NEXT_LEN_MASK   0x00000FFF
+#define CTRL_WLAN_WAKEUP     0x00001000
+#define CTRL_WLAN_READY      0x00002000
+
+#define IGPR_RW          0x80000000
+#define IGPR_INDEX       0x7F000000
+#define IGPR_VALUE       0x00FFFFFF
+
+#endif /* WFX_HWIO_H */

drivers/staging/wfx/main.c

@@ -11,10 +11,15 @@
  * Copyright (c) 2004-2006 Jean-Baptiste Note <jbnote@gmail.com>, et al.
  */
 #include <linux/module.h>
+#include <linux/of.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/mmc/sdio_func.h>
 #include <linux/spi/spi.h>
 #include <linux/etherdevice.h>
 
+#include "main.h"
+#include "wfx.h"
 #include "bus.h"
 #include "wfx_version.h"
 
@@ -23,6 +28,54 @@ MODULE_AUTHOR("Jérôme Pouiller <jerome.pouiller@silabs.com>");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(WFX_LABEL);
 
+struct gpio_desc *wfx_get_gpio(struct device *dev, int override, const char *label)
+{
+	struct gpio_desc *ret;
+	char label_buf[256];
+
+	if (override >= 0) {
+		snprintf(label_buf, sizeof(label_buf), "wfx_%s", label);
+		ret = ERR_PTR(devm_gpio_request_one(dev, override, GPIOF_OUT_INIT_LOW, label_buf));
+		if (!ret)
+			ret = gpio_to_desc(override);
+	} else if (override == -1) {
+		ret = NULL;
+	} else {
+		ret = devm_gpiod_get(dev, label, GPIOD_OUT_LOW);
+	}
+	if (IS_ERR(ret) || !ret) {
+		if (!ret || PTR_ERR(ret) == -ENOENT)
+			dev_warn(dev, "gpio %s is not defined\n", label);
+		else
+			dev_warn(dev, "error while requesting gpio %s\n", label);
+		ret = NULL;
+	} else {
+		dev_dbg(dev, "using gpio %d for %s\n", desc_to_gpio(ret), label);
+	}
+	return ret;
+}
+
+struct wfx_dev *wfx_init_common(struct device *dev,
+				const struct wfx_platform_data *pdata,
+				const struct hwbus_ops *hwbus_ops,
+				void *hwbus_priv)
+{
+	struct wfx_dev *wdev;
+
+	wdev = devm_kmalloc(dev, sizeof(*wdev), GFP_KERNEL);
+	if (!wdev)
+		return NULL;
+	wdev->dev = dev;
+	wdev->hwbus_ops = hwbus_ops;
+	wdev->hwbus_priv = hwbus_priv;
+	memcpy(&wdev->pdata, pdata, sizeof(*pdata));
+	return wdev;
+}
+
+void wfx_free_common(struct wfx_dev *wdev)
+{
+}
+
 static int __init wfx_core_init(void)
 {
 	int ret = 0;

drivers/staging/wfx/main.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Device probe and register.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ * Copyright (c) 2006, Michael Wu <flamingice@sourmilk.net>
+ * Copyright 2004-2006 Jean-Baptiste Note <jbnote@gmail.com>, et al.
+ */
+#ifndef WFX_MAIN_H
+#define WFX_MAIN_H
+
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+
+#include "bus.h"
+
+struct wfx_dev;
+
+struct wfx_platform_data {
+};
+
+struct wfx_dev *wfx_init_common(struct device *dev,
+				const struct wfx_platform_data *pdata,
+				const struct hwbus_ops *hwbus_ops,
+				void *hwbus_priv);
+void wfx_free_common(struct wfx_dev *wdev);
+
+struct gpio_desc *wfx_get_gpio(struct device *dev, int override,
+			       const char *label);
+
+#endif

drivers/staging/wfx/wfx.h

+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Common private data for Silicon Labs WFx chips.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ * Copyright (c) 2006, Michael Wu <flamingice@sourmilk.net>
+ * Copyright 2004-2006 Jean-Baptiste Note <jbnote@gmail.com>, et al.
+ */
+#ifndef WFX_H
+#define WFX_H
+
+#include "main.h"
+
+struct hwbus_ops;
+
+struct wfx_dev {
+	struct wfx_platform_data pdata;
+	struct device		*dev;
+	const struct hwbus_ops	*hwbus_ops;
+	void			*hwbus_priv;
+};
+
+#endif /* WFX_H */