[PATCH v3 03/20] staging: wfx: add I/O API

[Jerome Pouiller <Jerome.Pouiller@silabs.com>]

From: Jérôme Pouiller <jerome.pouiller@silabs.com>

hwio.c provides an abstraction to access different types of register of
the chip.

Note that only data register (aka FRAME_OUT) and control register are
used normal communication. Other registers are only used during chip
start up.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
---
 drivers/staging/wfx/Makefile |   1 +
 drivers/staging/wfx/hwio.c   | 327 +++++++++++++++++++++++++++++++++++
 drivers/staging/wfx/hwio.h   |  27 +++
 3 files changed, 355 insertions(+)
 create mode 100644 drivers/staging/wfx/hwio.c

diff --git a/drivers/staging/wfx/Makefile b/drivers/staging/wfx/Makefile
index 74939a5a0a1c..e860845186cf 100644
--- a/drivers/staging/wfx/Makefile
+++ b/drivers/staging/wfx/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 wfx-y := \
+	hwio.o \
 	main.o
 wfx-$(CONFIG_SPI) += bus_spi.o
 wfx-$(subst m,y,$(CONFIG_MMC)) += bus_sdio.o
diff --git a/drivers/staging/wfx/hwio.c b/drivers/staging/wfx/hwio.c
new file mode 100644
index 000000000000..fa626a49dd8a
--- /dev/null
+++ b/drivers/staging/wfx/hwio.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Low-level I/O functions.
+ *
+ * Copyright (c) 2017-2019, Silicon Laboratories, Inc.
+ * Copyright (c) 2010, ST-Ericsson
+ */
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+
+#include "hwio.h"
+#include "wfx.h"
+#include "bus.h"
+
+/*
+ * Internal helpers.
+ *
+ * About CONFIG_VMAP_STACK:
+ * When CONFIG_VMAP_STACK is enabled, it is not possible to run DMA on stack
+ * allocated data. Functions below that work with registers (aka functions
+ * ending with "32") automatically reallocate buffers with kmalloc. However,
+ * functions that work with arbitrary length buffers let's caller to handle
+ * memory location. In doubt, enable CONFIG_DEBUG_SG to detect badly located
+ * buffer.
+ */
+
+static int read32(struct wfx_dev *wdev, int reg, u32 *val)
+{
+	int ret;
+	__le32 *tmp = kmalloc(sizeof(u32), GFP_KERNEL);
+
+	*val = ~0; // Never return undefined value
+	if (!tmp)
+		return -ENOMEM;
+	ret = wdev->hwbus_ops->copy_from_io(wdev->hwbus_priv, reg, tmp, sizeof(u32));
+	if (ret >= 0)
+		*val = le32_to_cpu(*tmp);
+	kfree(tmp);
+	if (ret)
+		dev_err(wdev->dev, "%s: bus communication error: %d\n", __func__, ret);
+	return ret;
+}
+
+static int write32(struct wfx_dev *wdev, int reg, u32 val)
+{
+	int ret;
+	__le32 *tmp = kmalloc(sizeof(u32), GFP_KERNEL);
+
+	if (!tmp)
+		return -ENOMEM;
+	*tmp = cpu_to_le32(val);
+	ret = wdev->hwbus_ops->copy_to_io(wdev->hwbus_priv, reg, tmp, sizeof(u32));
+	kfree(tmp);
+	if (ret)
+		dev_err(wdev->dev, "%s: bus communication error: %d\n", __func__, ret);
+	return ret;
+}
+
+static int read32_locked(struct wfx_dev *wdev, int reg, u32 *val)
+{
+	int ret;
+
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = read32(wdev, reg, val);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	return ret;
+}
+
+static int write32_locked(struct wfx_dev *wdev, int reg, u32 val)
+{
+	int ret;
+
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = write32(wdev, reg, val);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	return ret;
+}
+
+static int write32_bits_locked(struct wfx_dev *wdev, int reg, u32 mask, u32 val)
+{
+	int ret;
+	u32 val_r, val_w;
+
+	WARN_ON(~mask & val);
+	val &= mask;
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = read32(wdev, reg, &val_r);
+	if (ret < 0)
+		goto err;
+	val_w = (val_r & ~mask) | val;
+	if (val_w != val_r) {
+		ret = write32(wdev, reg, val_w);
+	}
+err:
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	return ret;
+}
+
+static int indirect_read(struct wfx_dev *wdev, int reg, u32 addr, void *buf, size_t len)
+{
+	int ret;
+	int i;
+	u32 cfg;
+	u32 prefetch;
+
+	WARN_ON(len >= 0x2000);
+	WARN_ON(reg != WFX_REG_AHB_DPORT && reg != WFX_REG_SRAM_DPORT);
+
+	if (reg == WFX_REG_AHB_DPORT)
+		prefetch = CFG_PREFETCH_AHB;
+	else if (reg == WFX_REG_SRAM_DPORT)
+		prefetch = CFG_PREFETCH_SRAM;
+	else
+		return -ENODEV;
+
+	ret = write32(wdev, WFX_REG_BASE_ADDR, addr);
+	if (ret < 0)
+		goto err;
+
+	ret = read32(wdev, WFX_REG_CONFIG, &cfg);
+	if (ret < 0)
+		goto err;
+
+	ret = write32(wdev, WFX_REG_CONFIG, cfg | prefetch);
+	if (ret < 0)
+		goto err;
+
+	for (i = 0; i < 20; i++) {
+		ret = read32(wdev, WFX_REG_CONFIG, &cfg);
+		if (ret < 0)
+			goto err;
+		if (!(cfg & prefetch))
+			break;
+		udelay(200);
+	}
+	if (i == 20) {
+		ret = -ETIMEDOUT;
+		goto err;
+	}
+
+	ret = wdev->hwbus_ops->copy_from_io(wdev->hwbus_priv, reg, buf, len);
+
+err:
+	if (ret < 0)
+		memset(buf, 0xFF, len); // Never return undefined value
+	return ret;
+}
+
+static int indirect_write(struct wfx_dev *wdev, int reg, u32 addr, const void *buf, size_t len)
+{
+	int ret;
+
+	WARN_ON(len >= 0x2000);
+	WARN_ON(reg != WFX_REG_AHB_DPORT && reg != WFX_REG_SRAM_DPORT);
+	ret = write32(wdev, WFX_REG_BASE_ADDR, addr);
+	if (ret < 0)
+		return ret;
+
+	return wdev->hwbus_ops->copy_to_io(wdev->hwbus_priv, reg, buf, len);
+}
+
+static int indirect_read_locked(struct wfx_dev *wdev, int reg, u32 addr, void *buf, size_t len)
+{
+	int ret;
+
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = indirect_read(wdev, reg, addr, buf, len);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	return ret;
+}
+
+static int indirect_write_locked(struct wfx_dev *wdev, int reg, u32 addr, const void *buf, size_t len)
+{
+	int ret;
+
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = indirect_write(wdev, reg, addr, buf, len);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	return ret;
+}
+
+static int indirect_read32_locked(struct wfx_dev *wdev, int reg, u32 addr, u32 *val)
+{
+	int ret;
+	__le32 *tmp = kmalloc(sizeof(u32), GFP_KERNEL);
+
+	if (!tmp)
+		return -ENOMEM;
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = indirect_read(wdev, reg, addr, tmp, sizeof(u32));
+	*val = cpu_to_le32(*tmp);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	kfree(tmp);
+	return ret;
+}
+
+static int indirect_write32_locked(struct wfx_dev *wdev, int reg, u32 addr, u32 val)
+{
+	int ret;
+	__le32 *tmp = kmalloc(sizeof(u32), GFP_KERNEL);
+
+	if (!tmp)
+		return -ENOMEM;
+	*tmp = cpu_to_le32(val);
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = indirect_write(wdev, reg, addr, tmp, sizeof(u32));
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	kfree(tmp);
+	return ret;
+}
+
+int wfx_data_read(struct wfx_dev *wdev, void *buf, size_t len)
+{
+	int ret;
+
+	WARN((long) buf & 3, "%s: unaligned buffer", __func__);
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = wdev->hwbus_ops->copy_from_io(wdev->hwbus_priv, WFX_REG_IN_OUT_QUEUE, buf, len);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	if (ret)
+		dev_err(wdev->dev, "%s: bus communication error: %d\n", __func__, ret);
+	return ret;
+}
+
+int wfx_data_write(struct wfx_dev *wdev, const void *buf, size_t len)
+{
+	int ret;
+
+	WARN((long) buf & 3, "%s: unaligned buffer", __func__);
+	wdev->hwbus_ops->lock(wdev->hwbus_priv);
+	ret = wdev->hwbus_ops->copy_to_io(wdev->hwbus_priv, WFX_REG_IN_OUT_QUEUE, buf, len);
+	wdev->hwbus_ops->unlock(wdev->hwbus_priv);
+	if (ret)
+		dev_err(wdev->dev, "%s: bus communication error: %d\n", __func__, ret);
+	return ret;
+}
+
+int sram_buf_read(struct wfx_dev *wdev, u32 addr, void *buf, size_t len)
+{
+	return indirect_read_locked(wdev, WFX_REG_SRAM_DPORT, addr, buf, len);
+}
+
+int ahb_buf_read(struct wfx_dev *wdev, u32 addr, void *buf, size_t len)
+{
+	return indirect_read_locked(wdev, WFX_REG_AHB_DPORT, addr, buf, len);
+}
+
+int sram_buf_write(struct wfx_dev *wdev, u32 addr, const void *buf, size_t len)
+{
+	return indirect_write_locked(wdev, WFX_REG_SRAM_DPORT, addr, buf, len);
+}
+
+int ahb_buf_write(struct wfx_dev *wdev, u32 addr, const void *buf, size_t len)
+{
+	return indirect_write_locked(wdev, WFX_REG_AHB_DPORT, addr, buf, len);
+}
+
+int sram_reg_read(struct wfx_dev *wdev, u32 addr, u32 *val)
+{
+	return indirect_read32_locked(wdev, WFX_REG_SRAM_DPORT, addr, val);
+}
+
+int ahb_reg_read(struct wfx_dev *wdev, u32 addr, u32 *val)
+{
+	return indirect_read32_locked(wdev, WFX_REG_AHB_DPORT, addr, val);
+}
+
+int sram_reg_write(struct wfx_dev *wdev, u32 addr, u32 val)
+{
+	return indirect_write32_locked(wdev, WFX_REG_SRAM_DPORT, addr, val);
+}
+
+int ahb_reg_write(struct wfx_dev *wdev, u32 addr, u32 val)
+{
+	return indirect_write32_locked(wdev, WFX_REG_AHB_DPORT, addr, val);
+}
+
+int config_reg_read(struct wfx_dev *wdev, u32 *val)
+{
+	return read32_locked(wdev, WFX_REG_CONFIG, val);
+}
+
+int config_reg_write(struct wfx_dev *wdev, u32 val)
+{
+	return write32_locked(wdev, WFX_REG_CONFIG, val);
+}
+
+int config_reg_write_bits(struct wfx_dev *wdev, u32 mask, u32 val)
+{
+	return write32_bits_locked(wdev, WFX_REG_CONFIG, mask, val);
+}
+
+int control_reg_read(struct wfx_dev *wdev, u32 *val)
+{
+	return read32_locked(wdev, WFX_REG_CONTROL, val);
+}
+
+int control_reg_write(struct wfx_dev *wdev, u32 val)
+{
+	return write32_locked(wdev, WFX_REG_CONTROL, val);
+}
+
+int control_reg_write_bits(struct wfx_dev *wdev, u32 mask, u32 val)
+{
+	return write32_bits_locked(wdev, WFX_REG_CONTROL, mask, val);
+}
+
+int igpr_reg_read(struct wfx_dev *wdev, int index, u32 *val)
+{
+	int ret;
+
+	*val = ~0; // Never return undefined value
+	ret = write32_locked(wdev, WFX_REG_SET_GEN_R_W, IGPR_RW | index << 24);
+	if (ret)
+		return ret;
+	ret = read32_locked(wdev, WFX_REG_SET_GEN_R_W, val);
+	if (ret)
+		return ret;
+	*val &= IGPR_VALUE;
+	return ret;
+}
+
+int igpr_reg_write(struct wfx_dev *wdev, int index, u32 val)
+{
+	return write32_locked(wdev, WFX_REG_SET_GEN_R_W, index << 24 | val);
+}
diff --git a/drivers/staging/wfx/hwio.h b/drivers/staging/wfx/hwio.h
index c490014c1df8..906524f71fd1 100644
--- a/drivers/staging/wfx/hwio.h
+++ b/drivers/staging/wfx/hwio.h
@@ -8,6 +8,25 @@
 #ifndef WFX_HWIO_H
 #define WFX_HWIO_H
 
+#include <linux/types.h>
+
+struct wfx_dev;
+
+int wfx_data_read(struct wfx_dev *wdev, void *buf, size_t buf_len);
+int wfx_data_write(struct wfx_dev *wdev, const void *buf, size_t buf_len);
+
+int sram_buf_read(struct wfx_dev *wdev, u32 addr, void *buf, size_t len);
+int sram_buf_write(struct wfx_dev *wdev, u32 addr, const void *buf, size_t len);
+
+int ahb_buf_read(struct wfx_dev *wdev, u32 addr, void *buf, size_t len);
+int ahb_buf_write(struct wfx_dev *wdev, u32 addr, const void *buf, size_t len);
+
+int sram_reg_read(struct wfx_dev *wdev, u32 addr, u32 *val);
+int sram_reg_write(struct wfx_dev *wdev, u32 addr, u32 val);
+
+int ahb_reg_read(struct wfx_dev *wdev, u32 addr, u32 *val);
+int ahb_reg_write(struct wfx_dev *wdev, u32 addr, u32 val);
+
 #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
@@ -36,13 +55,21 @@
 #define CFG_DEVICE_ID_MAJOR        0x07000000
 #define CFG_DEVICE_ID_RESERVED     0x78000000
 #define CFG_DEVICE_ID_TYPE         0x80000000
+int config_reg_read(struct wfx_dev *wdev, u32 *val);
+int config_reg_write(struct wfx_dev *wdev, u32 val);
+int config_reg_write_bits(struct wfx_dev *wdev, u32 mask, u32 val);
 
 #define CTRL_NEXT_LEN_MASK   0x00000FFF
 #define CTRL_WLAN_WAKEUP     0x00001000
 #define CTRL_WLAN_READY      0x00002000
+int control_reg_read(struct wfx_dev *wdev, u32 *val);
+int control_reg_write(struct wfx_dev *wdev, u32 val);
+int control_reg_write_bits(struct wfx_dev *wdev, u32 mask, u32 val);
 
 #define IGPR_RW          0x80000000
 #define IGPR_INDEX       0x7F000000
 #define IGPR_VALUE       0x00FFFFFF
+int igpr_reg_read(struct wfx_dev *wdev, int index, u32 *val);
+int igpr_reg_write(struct wfx_dev *wdev, int index, u32 val);
 
 #endif /* WFX_HWIO_H */
-- 
2.20.1