From: fariyaf@gmail.com
To: linux-wireless@vger.kernel.org
Cc: Fariya Fatima <fariyaf@gmail.com>
Subject: [PATCH v4 09/11] rsi: SDIO functionality.
Date: Mon, 10 Mar 2014 20:56:37 +0530
Message-Id: <1394465199-10042-10-git-send-email-fariyaf@gmail.com> (sfid-20140310_162731_111014_66ECF3D6)
In-Reply-To: <1394465199-10042-1-git-send-email-fariyaf@gmail.com>
References: <1394465199-10042-1-git-send-email-fariyaf@gmail.com>
Sender: linux-wireless-owner@vger.kernel.org

From: Fariya Fatima <fariyaf@gmail.com>

Signed-off-by: Fariya Fatima <fariyaf@gmail.com>

This patch add the rsi_sdio module, enabling SDIO interface
for the 91x chipsets.
---
 drivers/net/wireless/rsi/rsi_91x_sdio.c |  845 +++++++++++++++++++++++++++++++
 1 files changed, 845 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/wireless/rsi/rsi_91x_sdio.c

diff --git a/drivers/net/wireless/rsi/rsi_91x_sdio.c b/drivers/net/wireless/rsi/rsi_91x_sdio.c
new file mode 100644
index 0000000..98db9e6
--- /dev/null
+++ b/drivers/net/wireless/rsi/rsi_91x_sdio.c
@@ -0,0 +1,845 @@
+/**
+ * Copyright (c) 2014 Redpine Signals Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include <linux/module.h>
+#include "rsi_sdio.h"
+#include "rsi_common.h"
+
+/**
+ * rsi_sdio_set_cmd52_arg() - This function prepares cmd 52 read/write arg.
+ * @rw: Read/write
+ * @func: function number
+ * @raw: indicates whether to perform read after write
+ * @address: address to which to read/write
+ * @writedata: data to write
+ *
+ * Return: argument
+ */
+static u32 rsi_sdio_set_cmd52_arg(bool rw,
+				  u8 func,
+				  u8 raw,
+				  u32 address,
+				  u8 writedata)
+{
+	return ((rw & 1) << 31) | ((func & 0x7) << 28) |
+		((raw & 1) << 27) | (1 << 26) |
+		((address & 0x1FFFF) << 9) | (1 << 8) |
+		(writedata & 0xFF);
+}
+
+/**
+ * rsi_cmd52writebyte() - This function issues cmd52 byte write onto the card.
+ * @card: Pointer to the mmc_card.
+ * @address: Address to write.
+ * @byte: Data to write.
+ *
+ * Return: Write status.
+ */
+static int rsi_cmd52writebyte(struct mmc_card *card,
+			      u32 address,
+			      u8 byte)
+{
+	struct mmc_command io_cmd;
+	u32 arg;
+
+	memset(&io_cmd, 0, sizeof(io_cmd));
+	arg = rsi_sdio_set_cmd52_arg(1, 0, 0, address, byte);
+	io_cmd.opcode = SD_IO_RW_DIRECT;
+	io_cmd.arg = arg;
+	io_cmd.flags = MMC_RSP_R5 | MMC_CMD_AC;
+
+	return mmc_wait_for_cmd(card->host, &io_cmd, 0);
+}
+
+/**
+ * rsi_cmd52readbyte() - This function issues cmd52 byte read onto the card.
+ * @card: Pointer to the mmc_card.
+ * @address: Address to read from.
+ * @byte: Variable to store read value.
+ *
+ * Return: Read status.
+ */
+static int rsi_cmd52readbyte(struct mmc_card *card,
+			     u32 address,
+			     u8 *byte)
+{
+	struct mmc_command io_cmd;
+	u32 arg;
+	int err;
+
+	memset(&io_cmd, 0, sizeof(io_cmd));
+	arg = rsi_sdio_set_cmd52_arg(0, 0, 0, address, 0);
+	io_cmd.opcode = SD_IO_RW_DIRECT;
+	io_cmd.arg = arg;
+	io_cmd.flags = MMC_RSP_R5 | MMC_CMD_AC;
+
+	err = mmc_wait_for_cmd(card->host, &io_cmd, 0);
+	if ((!err) && (byte))
+		*byte =  io_cmd.resp[0] & 0xFF;
+	return err;
+}
+
+/**
+ * rsi_issue_sdiocommand() - This function issues sdio commands.
+ * @func: Pointer to the sdio_func structure.
+ * @opcode: Opcode value.
+ * @arg: Arguments to pass.
+ * @flags: Flags which are set.
+ * @resp: Pointer to store response.
+ *
+ * Return: err: command status as 0 or -1.
+ */
+static int rsi_issue_sdiocommand(struct sdio_func *func,
+				 u32 opcode,
+				 u32 arg,
+				 u32 flags,
+				 u32 *resp)
+{
+	struct mmc_command cmd;
+	struct mmc_host *host;
+	int err;
+
+	host = func->card->host;
+
+	memset(&cmd, 0, sizeof(struct mmc_command));
+	cmd.opcode = opcode;
+	cmd.arg = arg;
+	cmd.flags = flags;
+	err = mmc_wait_for_cmd(host, &cmd, 3);
+
+	if ((!err) && (resp))
+		*resp = cmd.resp[0];
+
+	return err;
+}
+
+/**
+ * rsi_handle_interrupt() - This function is called upon the occurence
+ *			    of an interrupt.
+ * @function: Pointer to the sdio_func structure.
+ *
+ * Return: None.
+ */
+static void rsi_handle_interrupt(struct sdio_func *function)
+{
+	struct rsi_hw *adapter = sdio_get_drvdata(function);
+
+	sdio_release_host(function);
+	rsi_interrupt_handler(adapter);
+	sdio_claim_host(function);
+}
+
+/**
+ * rsi_reset_card() - This function resets and re-initializes the card.
+ * @pfunction: Pointer to the sdio_func structure.
+ *
+ * Return: None.
+ */
+static void rsi_reset_card(struct sdio_func *pfunction)
+{
+	int ret = 0;
+	int err;
+	struct mmc_card *card = pfunction->card;
+	struct mmc_host *host = card->host;
+	s32 bit = (fls(host->ocr_avail) - 1);
+	u8 cmd52_resp;
+	u32 clock, resp, i;
+	u16 rca;
+
+	/* Reset 9110 chip */
+	ret = rsi_cmd52writebyte(pfunction->card,
+				 SDIO_CCCR_ABORT,
+				 (1 << 3));
+
+	/* Card will not send any response as it is getting reset immediately
+	 * Hence expect a timeout status from host controller
+	 */
+	if (ret != -ETIMEDOUT)
+		rsi_dbg(ERR_ZONE, "%s: Reset failed : %d\n", __func__, ret);
+
+	/* Wait for few milli seconds to get rid of residue charges if any */
+	msleep(20);
+
+	/* Initialize the SDIO card */
+	host->ios.vdd = bit;
+	host->ios.chip_select = MMC_CS_DONTCARE;
+	host->ios.bus_mode = MMC_BUSMODE_OPENDRAIN;
+	host->ios.power_mode = MMC_POWER_UP;
+	host->ios.bus_width = MMC_BUS_WIDTH_1;
+	host->ios.timing = MMC_TIMING_LEGACY;
+	host->ops->set_ios(host, &host->ios);
+
+	/*
+	 * This delay should be sufficient to allow the power supply
+	 * to reach the minimum voltage.
+	 */
+	msleep(20);
+
+	host->ios.clock = host->f_min;
+	host->ios.power_mode = MMC_POWER_ON;
+	host->ops->set_ios(host, &host->ios);
+
+	/*
+	 * This delay must be at least 74 clock sizes, or 1 ms, or the
+	 * time required to reach a stable voltage.
+	 */
+	msleep(20);
+
+	/* Issue CMD0. Goto idle state */
+	host->ios.chip_select = MMC_CS_HIGH;
+	host->ops->set_ios(host, &host->ios);
+	msleep(20);
+	err = rsi_issue_sdiocommand(pfunction,
+				    MMC_GO_IDLE_STATE,
+				    0,
+				    (MMC_RSP_NONE | MMC_CMD_BC),
+				    NULL);
+	host->ios.chip_select = MMC_CS_DONTCARE;
+	host->ops->set_ios(host, &host->ios);
+	msleep(20);
+	host->use_spi_crc = 0;
+
+	if (err)
+		rsi_dbg(ERR_ZONE, "%s: CMD0 failed : %d\n", __func__, err);
+
+	if (!host->ocr_avail) {
+		/* Issue CMD5, arg = 0 */
+		err = rsi_issue_sdiocommand(pfunction,
+					    SD_IO_SEND_OP_COND,
+					    0,
+					    (MMC_RSP_R4 | MMC_CMD_BCR),
+					    &resp);
+		if (err)
+			rsi_dbg(ERR_ZONE, "%s: CMD5 failed : %d\n",
+				__func__, err);
+		host->ocr_avail = resp;
+	}
+
+	/* Issue CMD5, arg = ocr. Wait till card is ready  */
+	for (i = 0; i < 100; i++) {
+		err = rsi_issue_sdiocommand(pfunction,
+					    SD_IO_SEND_OP_COND,
+					    host->ocr_avail,
+					    (MMC_RSP_R4 | MMC_CMD_BCR),
+					    &resp);
+		if (err) {
+			rsi_dbg(ERR_ZONE, "%s: CMD5 failed : %d\n",
+				__func__, err);
+			break;
+		}
+
+		if (resp & MMC_CARD_BUSY)
+			break;
+		msleep(20);
+	}
+
+	if ((i == 100) || (err)) {
+		rsi_dbg(ERR_ZONE, "%s: card in not ready : %d %d\n",
+			__func__, i, err);
+		return;
+	}
+
+	/* Issue CMD3, get RCA */
+	err = rsi_issue_sdiocommand(pfunction,
+				    SD_SEND_RELATIVE_ADDR,
+				    0,
+				    (MMC_RSP_R6 | MMC_CMD_BCR),
+				    &resp);
+	if (err) {
+		rsi_dbg(ERR_ZONE, "%s: CMD3 failed : %d\n", __func__, err);
+		return;
+	}
+	rca = resp >> 16;
+	host->ios.bus_mode = MMC_BUSMODE_PUSHPULL;
+	host->ops->set_ios(host, &host->ios);
+
+	/* Issue CMD7, select card  */
+	err = rsi_issue_sdiocommand(pfunction,
+				    MMC_SELECT_CARD,
+				    (rca << 16),
+				    (MMC_RSP_R1 | MMC_CMD_AC),
+				    NULL);
+	if (err) {
+		rsi_dbg(ERR_ZONE, "%s: CMD7 failed : %d\n", __func__, err);
+		return;
+	}
+
+	/* Enable high speed */
+	if (card->host->caps & MMC_CAP_SD_HIGHSPEED) {
+		rsi_dbg(ERR_ZONE, "%s: Set high speed mode\n", __func__);
+		err = rsi_cmd52readbyte(card, SDIO_CCCR_SPEED, &cmd52_resp);
+		if (err) {
+			rsi_dbg(ERR_ZONE, "%s: CCCR speed reg read failed: %d\n",
+				__func__, err);
+			card->state &= ~MMC_STATE_HIGHSPEED;
+		} else {
+			err = rsi_cmd52writebyte(card,
+						 SDIO_CCCR_SPEED,
+						 (cmd52_resp | SDIO_SPEED_EHS));
+			if (err) {
+				rsi_dbg(ERR_ZONE,
+					"%s: CCR speed regwrite failed %d\n",
+					__func__, err);
+				return;
+			}
+			mmc_card_set_highspeed(card);
+			host->ios.timing = MMC_TIMING_SD_HS;
+			host->ops->set_ios(host, &host->ios);
+		}
+	}
+
+	/* Set clock */
+	if (mmc_card_highspeed(card))
+		clock = 50000000;
+	else
+		clock = card->cis.max_dtr;
+
+	if (clock > host->f_max)
+		clock = host->f_max;
+
+	host->ios.clock = clock;
+	host->ops->set_ios(host, &host->ios);
+
+	if (card->host->caps & MMC_CAP_4_BIT_DATA) {
+		/* CMD52: Set bus width & disable card detect resistor */
+		err = rsi_cmd52writebyte(card,
+					 SDIO_CCCR_IF,
+					 (SDIO_BUS_CD_DISABLE |
+					  SDIO_BUS_WIDTH_4BIT));
+		if (err) {
+			rsi_dbg(ERR_ZONE, "%s: Set bus mode failed : %d\n",
+				__func__, err);
+			return;
+		}
+		host->ios.bus_width = MMC_BUS_WIDTH_4;
+		host->ops->set_ios(host, &host->ios);
+	}
+}
+
+/**
+ * rsi_setclock() - This function sets the clock frequency.
+ * @adapter: Pointer to the adapter structure.
+ * @freq: Clock frequency.
+ *
+ * Return: 0 on success.
+ */
+static int rsi_setclock(struct rsi_hw *adapter, u32 freq)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	struct mmc_host *host = dev->pfunction->card->host;
+	u32 clock;
+
+	clock = freq * 1000;
+	if (clock > host->f_max)
+		clock = host->f_max;
+	host->ios.clock = clock;
+	host->ops->set_ios(host, &host->ios);
+	return 0;
+}
+
+/**
+ * rsi_setblocklength() - This function sets the host block length.
+ * @adapter: Pointer to the adapter structure.
+ * @length: Block length to be set.
+ *
+ * Return: status: 0 on success, -1 on failure.
+ */
+static int rsi_setblocklength(struct rsi_hw *adapter, u32 length)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	int status;
+	rsi_dbg(INIT_ZONE, "%s: Setting the block length\n", __func__);
+
+	status = sdio_set_block_size(dev->pfunction, length);
+	dev->pfunction->max_blksize = 256;
+
+	rsi_dbg(INFO_ZONE,
+		"%s: Operational blk length is %d\n", __func__, length);
+	return status;
+}
+
+/**
+ * rsi_setupcard() - This function queries and sets the card's features.
+ * @adapter: Pointer to the adapter structure.
+ *
+ * Return: status: 0 on success, -1 on failure.
+ */
+static int rsi_setupcard(struct rsi_hw *adapter)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	int status = 0;
+
+	if (rsi_setclock(adapter, 50000)) {
+		rsi_dbg(INFO_ZONE,
+			"%s: Unsuccessful at setting clk\n", __func__);
+		return -1;
+	}
+
+	dev->tx_blk_size = 256;
+	status = rsi_setblocklength(adapter, dev->tx_blk_size);
+	if (status)
+		rsi_dbg(ERR_ZONE,
+			"%s: Unable to set block length\n", __func__);
+	return status;
+}
+
+static int rsi_init_sdio_interface(struct rsi_hw *adapter,
+				   struct sdio_func *pfunction)
+{
+	struct rsi_91x_sdiodev *rsi_91x_dev;
+	int status = -1;
+
+	rsi_91x_dev = kzalloc(sizeof(*rsi_91x_dev), GFP_KERNEL);
+	if (!rsi_91x_dev)
+		return status;
+
+	adapter->rsi_dev = rsi_91x_dev;
+
+	sdio_claim_host(pfunction);
+
+	pfunction->enable_timeout = 100;
+	status = sdio_enable_func(pfunction);
+	if (status) {
+		rsi_dbg(ERR_ZONE, "%s: Failed to enable interface\n", __func__);
+		sdio_release_host(pfunction);
+		return status;
+	}
+
+	rsi_dbg(INIT_ZONE, "%s: Enabled the interface\n", __func__);
+
+	rsi_91x_dev->pfunction = pfunction;
+	adapter->device = &pfunction->dev;
+
+	sdio_set_drvdata(pfunction, adapter);
+
+	status = rsi_setupcard(adapter);
+	if (status) {
+		rsi_dbg(ERR_ZONE, "%s: Failed to setup card\n", __func__);
+		goto fail;
+	}
+
+	rsi_dbg(INIT_ZONE, "%s: Setup card succesfully\n", __func__);
+
+	status = rsi_init_sdio_slave_regs(adapter);
+	if (status) {
+		rsi_dbg(ERR_ZONE, "%s: Failed to init slave regs\n", __func__);
+		goto fail;
+	}
+	sdio_release_host(pfunction);
+
+	adapter->host_intf_write_pkt = rsi_host_intf_write_pkt;
+	adapter->host_intf_read_pkt = rsi_host_intf_read_pkt;
+	adapter->determine_event_timeout = rsi_determine_event_timeout;
+	adapter->check_hw_queue_status = rsi_read_buffer_status_register;
+
+#ifdef CONFIG_RSI_DEBUGFS
+	adapter->num_debugfs_entries = MAX_DEBUGFS_ENTRIES;
+#endif
+	return status;
+fail:
+	sdio_disable_func(pfunction);
+	sdio_release_host(pfunction);
+	return status;
+}
+
+/**
+ * rsi_read_register() - This function reads one byte of information
+ *			 from a register.
+ * @adapter: Pointer to the adapter structure.
+ * @addr: Address of the register.
+ * @data: Pointer to the data that stores the data read.
+ *
+ * Return: 0 on success, -1 on failure.
+ */
+int rsi_read_register(struct rsi_hw *adapter,
+		      u32 addr,
+		      u8 *data)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	u8 fun_num = 0;
+	int status;
+
+	sdio_claim_host(dev->pfunction);
+
+	if (fun_num == 0)
+		*data = sdio_f0_readb(dev->pfunction, addr, &status);
+	else
+		*data = sdio_readb(dev->pfunction, addr, &status);
+
+	sdio_release_host(dev->pfunction);
+
+	return status;
+}
+
+/**
+ * rsi_write_register() - This function writes one byte of information
+ *			  into a register.
+ * @adapter: Pointer to the adapter structure.
+ * @function: Function Number.
+ * @addr: Address of the register.
+ * @data: Pointer to the data tha has to be written.
+ *
+ * Return: 0 on success, -1 on failure.
+ */
+int rsi_write_register(struct rsi_hw *adapter,
+		       u8 function,
+		       u32 addr,
+		       u8 *data)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	int status = 0;
+
+	sdio_claim_host(dev->pfunction);
+
+	if (function == 0)
+		sdio_f0_writeb(dev->pfunction, *data, addr, &status);
+	else
+		sdio_writeb(dev->pfunction, *data, addr, &status);
+
+	sdio_release_host(dev->pfunction);
+
+	return status;
+}
+
+/**
+ * rsi_ack_interrupt() - This function acks the interrupt received.
+ * @adapter: Pointer to the adapter structure.
+ * @int_bit: Interrupt bit to write into register.
+ *
+ * Return: None.
+ */
+void rsi_ack_interrupt(struct rsi_hw *adapter, u8 int_bit)
+{
+	int status;
+	status = rsi_write_register(adapter,
+				    1,
+				    (SDIO_FUN1_INTR_CLR_REG |
+				     RSI_SD_REQUEST_MASTER),
+				    &int_bit);
+	if (status)
+		rsi_dbg(ERR_ZONE, "%s: unable to send ack\n", __func__);
+}
+
+
+
+/**
+ * rsi_read_register_multiple() - This function read multiple bytes of
+ *				  information from the SD card.
+ * @adapter: Pointer to the adapter structure.
+ * @addr: Address of the register.
+ * @count: Number of multiple bytes to be read.
+ * @data: Pointer to the read data.
+ *
+ * Return: 0 on success, -1 on failure.
+ */
+static int rsi_read_register_multiple(struct rsi_hw *adapter,
+				      u32 addr,
+				      u32 count,
+				      u8 *data)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	u32 status;
+
+	sdio_claim_host(dev->pfunction);
+
+	status =  sdio_readsb(dev->pfunction, data, addr, count);
+
+	sdio_release_host(dev->pfunction);
+
+	if (status != 0)
+		rsi_dbg(ERR_ZONE, "%s: Synch Cmd53 read failed\n", __func__);
+	return status;
+}
+
+/**
+ * rsi_write_register_multiple() - This function writes multiple bytes of
+ *				   information to the SD card.
+ * @adapter: Pointer to the adapter structure.
+ * @addr: Address of the register.
+ * @data: Pointer to the data that has to be written.
+ * @count: Number of multiple bytes to be written.
+ *
+ * Return: 0 on success, -1 on failure.
+ */
+int rsi_write_register_multiple(struct rsi_hw *adapter,
+				u32 addr,
+				u8 *data,
+				u32 count)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	int status = 0;
+
+	if (dev->write_fail > 1) {
+		rsi_dbg(ERR_ZONE, "%s: Stopping card writes\n", __func__);
+		return 0;
+	} else if (dev->write_fail == 1) {
+		/**
+		 * Assuming it is a CRC failure, we want to allow another
+		 *  card write
+		 */
+		rsi_dbg(ERR_ZONE, "%s: Continue card writes\n", __func__);
+		dev->write_fail++;
+	}
+
+	sdio_claim_host(dev->pfunction);
+
+	status = sdio_writesb(dev->pfunction, addr, data, count);
+
+	sdio_release_host(dev->pfunction);
+
+	if (status) {
+		rsi_dbg(ERR_ZONE, "%s: Synch Cmd53 write failed %d\n",
+			__func__, status);
+		dev->write_fail = 2;
+	} else {
+		memcpy(dev->prev_desc, data, FRAME_DESC_SZ);
+	}
+	return status;
+}
+
+/**
+ * rsi_host_intf_write_pkt() - This function writes the packet to the device.
+ * @adapter: Pointer to the adapter structure.
+ * @pkt: Pointer to the data to be written on to the device.
+ * @len: length of the data to be written on to the device.
+ *
+ * Return: 0 on success, -1 on failure.
+ */
+int rsi_host_intf_write_pkt(struct rsi_hw *adapter,
+			    u8 *pkt,
+			    u32 len)
+{
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+	u32 block_size = dev->tx_blk_size;
+	u32 num_blocks, address, length;
+	u32 queueno;
+	int status = 0;
+
+	queueno = ((pkt[1] >> 4) & 0xf);
+
+	num_blocks = len / block_size;
+
+	if (len % block_size)
+		num_blocks++;
+
+	address = (num_blocks * block_size | (queueno << 12));
+	length  = num_blocks * block_size;
+
+	status = rsi_write_register_multiple(adapter,
+					     address,
+					     (u8 *)pkt,
+					     length);
+	if (status)
+		rsi_dbg(ERR_ZONE, "%s: Unable to write onto the card: %d\n",
+			__func__, status);
+	rsi_dbg(DATA_TX_ZONE, "%s: Successfully written onto card\n", __func__);
+	return status;
+}
+
+/**
+ * rsi_host_intf_read_pkt() - This function reads the packet from the SD card.
+ * @adapter: Pointer to the adapter data structure.
+ * @pkt: Pointer to the packet data to be read from the the device.
+ * @length: Length of the data to be read from the device.
+ *
+ * Return: 0 on success, -1 on failure.
+ */
+int rsi_host_intf_read_pkt(struct rsi_hw *adapter,
+			   u8 *pkt,
+			   u32 length)
+{
+	int status  = 0;
+
+	if (!length) {
+		rsi_dbg(ERR_ZONE, "%s: Pkt size is zero\n", __func__);
+		return status;
+	}
+
+	status = rsi_read_register_multiple(adapter,
+					    length,
+					    length, /*num of bytes*/
+					    (u8 *)pkt);
+
+	if (status)
+		rsi_dbg(ERR_ZONE, "%s: Failed to read frame: %d\n", __func__,
+			status);
+	return status;
+}
+
+/**
+ * rsi_probe() - This function is called by kernel when the driver provided
+ *		 Vendor and device IDs are matched. All the initialization
+ *		 work is done here.
+ * @pfunction: Pointer to the sdio_func structure.
+ * @id: Pointer to sdio_device_id structure.
+ *
+ * Return: 0 on success, 1 on failure.
+ */
+static int rsi_probe(struct sdio_func *pfunction,
+		     const struct sdio_device_id *id)
+{
+	struct rsi_hw *adapter;
+
+	rsi_dbg(INIT_ZONE, "%s: Init function called\n", __func__);
+
+	adapter = rsi_91x_init();
+	if (!adapter) {
+		rsi_dbg(ERR_ZONE, "%s: Failed to init os intf ops\n",
+			__func__);
+		return 1;
+	}
+
+	if (rsi_init_sdio_interface(adapter, pfunction)) {
+		rsi_dbg(ERR_ZONE, "%s: Failed to init sdio interface\n",
+			__func__);
+		goto fail;
+	}
+
+	if (rsi_device_init(adapter->priv)) {
+		rsi_dbg(ERR_ZONE, "%s: Failed in device init\n", __func__);
+		sdio_claim_host(pfunction);
+		sdio_disable_func(pfunction);
+		sdio_release_host(pfunction);
+		goto fail;
+	}
+
+	sdio_claim_host(pfunction);
+	if (sdio_claim_irq(pfunction, rsi_handle_interrupt)) {
+		rsi_dbg(ERR_ZONE, "%s: Failed to request IRQ\n", __func__);
+		sdio_release_host(pfunction);
+		goto fail;
+	}
+
+	sdio_release_host(pfunction);
+	rsi_dbg(INIT_ZONE, "%s: Registered Interrupt handler\n", __func__);
+
+	return 0;
+fail:
+	rsi_91x_deinit(adapter);
+	rsi_dbg(ERR_ZONE, "%s: Failed in probe...Exiting\n", __func__);
+	return 1;
+}
+
+/**
+ * rsi_disconnect() - This function performs the reverse of the probe function.
+ * @pfunction: Pointer to the sdio_func structure.
+ *
+ * Return: void.
+ */
+static void rsi_disconnect(struct sdio_func *pfunction)
+{
+	struct rsi_hw *adapter = sdio_get_drvdata(pfunction);
+	struct rsi_91x_sdiodev *dev =
+		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
+
+	if (!adapter)
+		return;
+
+	dev->write_fail = 2;
+	rsi_mac80211_detach(adapter);
+
+	sdio_claim_host(pfunction);
+	sdio_release_irq(pfunction);
+	sdio_disable_func(pfunction);
+	rsi_91x_deinit(adapter);
+	/* Resetting to take care of the case, where-in driver is re-loaded */
+	rsi_reset_card(pfunction);
+	sdio_release_host(pfunction);
+}
+
+#ifdef CONFIG_PM
+static int rsi_suspend(struct device *dev)
+{
+	/* Not yet implemented */
+	return -ENOSYS;
+}
+
+static int rsi_resume(struct device *dev)
+{
+	/* Not yet implemented */
+	return -ENOSYS;
+}
+
+static const struct dev_pm_ops rsi_pm_ops = {
+	.suspend = rsi_suspend,
+	.resume = rsi_resume,
+};
+#endif
+
+static const struct sdio_device_id rsi_dev_table[] =  {
+	{ SDIO_DEVICE(0x303, 0x100) },
+	{ SDIO_DEVICE(0x041B, 0x0301) },
+	{ SDIO_DEVICE(0x041B, 0x0201) },
+	{ SDIO_DEVICE(0x041B, 0x9330) },
+	{ /* Blank */},
+};
+
+static struct sdio_driver rsi_driver = {
+	.name       = "RSI-SDIO WLAN",
+	.probe      = rsi_probe,
+	.remove     = rsi_disconnect,
+	.id_table   = rsi_dev_table,
+#ifdef CONFIG_PM
+	.drv = {
+		.pm = &rsi_pm_ops,
+	}
+#endif
+};
+
+/**
+ * rsi_module_init() - This function registers the sdio module.
+ * @void: Void.
+ *
+ * Return: 0 on success.
+ */
+static int rsi_module_init(void)
+{
+	sdio_register_driver(&rsi_driver);
+	rsi_dbg(INIT_ZONE, "%s: Registering driver\n", __func__);
+	return 0;
+}
+
+/**
+ * rsi_module_exit() - This function unregisters the sdio module.
+ * @void: Void.
+ *
+ * Return: None.
+ */
+static void rsi_module_exit(void)
+{
+	sdio_unregister_driver(&rsi_driver);
+	rsi_dbg(INFO_ZONE, "%s: Unregistering driver\n", __func__);
+}
+
+module_init(rsi_module_init);
+module_exit(rsi_module_exit);
+
+MODULE_AUTHOR("Redpine Signals Inc");
+MODULE_DESCRIPTION("Common SDIO layer for RSI drivers");
+MODULE_SUPPORTED_DEVICE("RSI-91x");
+MODULE_DEVICE_TABLE(sdio, rsi_dev_table);
+MODULE_FIRMWARE(FIRMWARE_RSI9113);
+MODULE_VERSION("0.1");
+MODULE_LICENSE("Dual BSD/GPL");
-- 
1.7.5.4