xref: /kernel/linux/linux-5.10/drivers/char/xilinx_hwicap/fifo_icap.c

/*****************************************************************************
 *
 *     Author: Xilinx, Inc.
 *
 *     This program is free software; you can redistribute it and/or modify it
 *     under the terms of the GNU General Public License as published by the
 *     Free Software Foundation; either version 2 of the License, or (at your
 *     option) any later version.
 *
 *     XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS"
 *     AS A COURTESY TO YOU, SOLELY FOR USE IN DEVELOPING PROGRAMS AND
 *     SOLUTIONS FOR XILINX DEVICES.  BY PROVIDING THIS DESIGN, CODE,
 *     OR INFORMATION AS ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE,
 *     APPLICATION OR STANDARD, XILINX IS MAKING NO REPRESENTATION
 *     THAT THIS IMPLEMENTATION IS FREE FROM ANY CLAIMS OF INFRINGEMENT,
 *     AND YOU ARE RESPONSIBLE FOR OBTAINING ANY RIGHTS YOU MAY REQUIRE
 *     FOR YOUR IMPLEMENTATION.  XILINX EXPRESSLY DISCLAIMS ANY
 *     WARRANTY WHATSOEVER WITH RESPECT TO THE ADEQUACY OF THE
 *     IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OR
 *     REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE FROM CLAIMS OF
 *     INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *     FOR A PARTICULAR PURPOSE.
 *
 *     (c) Copyright 2007-2008 Xilinx Inc.
 *     All rights reserved.
 *
 *     You should have received a copy of the GNU General Public License along
 *     with this program; if not, write to the Free Software Foundation, Inc.,
 *     675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *****************************************************************************/

#include "fifo_icap.h"

/* Register offsets for the XHwIcap device. */
#define XHI_GIER_OFFSET	0x1C  /* Device Global Interrupt Enable Reg */
#define XHI_IPISR_OFFSET 0x20  /* Interrupt Status Register */
#define XHI_IPIER_OFFSET 0x28  /* Interrupt Enable Register */
#define XHI_WF_OFFSET 0x100 /* Write FIFO */
#define XHI_RF_OFFSET 0x104 /* Read FIFO */
#define XHI_SZ_OFFSET 0x108 /* Size Register */
#define XHI_CR_OFFSET 0x10C /* Control Register */
#define XHI_SR_OFFSET 0x110 /* Status Register */
#define XHI_WFV_OFFSET 0x114 /* Write FIFO Vacancy Register */
#define XHI_RFO_OFFSET 0x118 /* Read FIFO Occupancy Register */

/* Device Global Interrupt Enable Register (GIER) bit definitions */

#define XHI_GIER_GIE_MASK 0x80000000 /* Global Interrupt enable Mask */

/**
 * HwIcap Device Interrupt Status/Enable Registers
 *
 * Interrupt Status Register (IPISR) : This register holds the
 * interrupt status flags for the device. These bits are toggle on
 * write.
 *
 * Interrupt Enable Register (IPIER) : This register is used to enable
 * interrupt sources for the device.
 * Writing a '1' to a bit enables the corresponding interrupt.
 * Writing a '0' to a bit disables the corresponding interrupt.
 *
 * IPISR/IPIER registers have the same bit definitions and are only defined
 * once.
 */
#define XHI_IPIXR_RFULL_MASK 0x00000008 /* Read FIFO Full */
#define XHI_IPIXR_WEMPTY_MASK 0x00000004 /* Write FIFO Empty */
#define XHI_IPIXR_RDP_MASK 0x00000002 /* Read FIFO half full */
#define XHI_IPIXR_WRP_MASK 0x00000001 /* Write FIFO half full */
#define XHI_IPIXR_ALL_MASK 0x0000000F /* Mask of all interrupts */

/* Control Register (CR) */
#define XHI_CR_SW_RESET_MASK 0x00000008 /* SW Reset Mask */
#define XHI_CR_FIFO_CLR_MASK 0x00000004 /* FIFO Clear Mask */
#define XHI_CR_READ_MASK 0x00000002 /* Read from ICAP to FIFO */
#define XHI_CR_WRITE_MASK 0x00000001 /* Write from FIFO to ICAP */


#define XHI_WFO_MAX_VACANCY 1024 /* Max Write FIFO Vacancy, in words */
#define XHI_RFO_MAX_OCCUPANCY 256 /* Max Read FIFO Occupancy, in words */
/* The maximum amount we can request from fifo_icap_get_configuration
   at once, in bytes. */
#define XHI_MAX_READ_TRANSACTION_WORDS 0xFFF


/**
 * fifo_icap_fifo_write - Write data to the write FIFO.
 * @drvdata: a pointer to the drvdata.
 * @data: the 32-bit value to be written to the FIFO.
 *
 * This function will silently fail if the fifo is full.
 **/
static inline void fifo_icap_fifo_write(struct hwicap_drvdata *drvdata,
		u32 data)
{
	dev_dbg(drvdata->dev, "fifo_write: %x\n", data);
	out_be32(drvdata->base_address + XHI_WF_OFFSET, data);
}

/**
 * fifo_icap_fifo_read - Read data from the Read FIFO.
 * @drvdata: a pointer to the drvdata.
 *
 * This function will silently fail if the fifo is empty.
 **/
static inline u32 fifo_icap_fifo_read(struct hwicap_drvdata *drvdata)
{
	u32 data = in_be32(drvdata->base_address + XHI_RF_OFFSET);
	dev_dbg(drvdata->dev, "fifo_read: %x\n", data);
	return data;
}

/**
 * fifo_icap_set_read_size - Set the the size register.
 * @drvdata: a pointer to the drvdata.
 * @data: the size of the following read transaction, in words.
 **/
static inline void fifo_icap_set_read_size(struct hwicap_drvdata *drvdata,
		u32 data)
{
	out_be32(drvdata->base_address + XHI_SZ_OFFSET, data);
}

/**
 * fifo_icap_start_config - Initiate a configuration (write) to the device.
 * @drvdata: a pointer to the drvdata.
 **/
static inline void fifo_icap_start_config(struct hwicap_drvdata *drvdata)
{
	out_be32(drvdata->base_address + XHI_CR_OFFSET, XHI_CR_WRITE_MASK);
	dev_dbg(drvdata->dev, "configuration started\n");
}

/**
 * fifo_icap_start_readback - Initiate a readback from the device.
 * @drvdata: a pointer to the drvdata.
 **/
static inline void fifo_icap_start_readback(struct hwicap_drvdata *drvdata)
{
	out_be32(drvdata->base_address + XHI_CR_OFFSET, XHI_CR_READ_MASK);
	dev_dbg(drvdata->dev, "readback started\n");
}

/**
 * fifo_icap_get_status - Get the contents of the status register.
 * @drvdata: a pointer to the drvdata.
 *
 * The status register contains the ICAP status and the done bit.
 *
 * D8 - cfgerr
 * D7 - dalign
 * D6 - rip
 * D5 - in_abort_l
 * D4 - Always 1
 * D3 - Always 1
 * D2 - Always 1
 * D1 - Always 1
 * D0 - Done bit
 **/
u32 fifo_icap_get_status(struct hwicap_drvdata *drvdata)
{
	u32 status = in_be32(drvdata->base_address + XHI_SR_OFFSET);
	dev_dbg(drvdata->dev, "Getting status = %x\n", status);
	return status;
}

/**
 * fifo_icap_busy - Return true if the ICAP is still processing a transaction.
 * @drvdata: a pointer to the drvdata.
 **/
static inline u32 fifo_icap_busy(struct hwicap_drvdata *drvdata)
{
	u32 status = in_be32(drvdata->base_address + XHI_SR_OFFSET);
	return (status & XHI_SR_DONE_MASK) ? 0 : 1;
}

/**
 * fifo_icap_write_fifo_vacancy - Query the write fifo available space.
 * @drvdata: a pointer to the drvdata.
 *
 * Return the number of words that can be safely pushed into the write fifo.
 **/
static inline u32 fifo_icap_write_fifo_vacancy(
		struct hwicap_drvdata *drvdata)
{
	return in_be32(drvdata->base_address + XHI_WFV_OFFSET);
}

/**
 * fifo_icap_read_fifo_occupancy - Query the read fifo available data.
 * @drvdata: a pointer to the drvdata.
 *
 * Return the number of words that can be safely read from the read fifo.
 **/
static inline u32 fifo_icap_read_fifo_occupancy(
		struct hwicap_drvdata *drvdata)
{
	return in_be32(drvdata->base_address + XHI_RFO_OFFSET);
}

/**
 * fifo_icap_set_configuration - Send configuration data to the ICAP.
 * @drvdata: a pointer to the drvdata.
 * @frame_buffer: a pointer to the data to be written to the
 *		ICAP device.
 * @num_words: the number of words (32 bit) to write to the ICAP
 *		device.

 * This function writes the given user data to the Write FIFO in
 * polled mode and starts the transfer of the data to
 * the ICAP device.
 **/
int fifo_icap_set_configuration(struct hwicap_drvdata *drvdata,
		u32 *frame_buffer, u32 num_words)
{

	u32 write_fifo_vacancy = 0;
	u32 retries = 0;
	u32 remaining_words;

	dev_dbg(drvdata->dev, "fifo_set_configuration\n");

	/*
	 * Check if the ICAP device is Busy with the last Read/Write
	 */
	if (fifo_icap_busy(drvdata))
		return -EBUSY;

	/*
	 * Set up the buffer pointer and the words to be transferred.
	 */
	remaining_words = num_words;

	while (remaining_words > 0) {
		/*
		 * Wait until we have some data in the fifo.
		 */
		while (write_fifo_vacancy == 0) {
			write_fifo_vacancy =
				fifo_icap_write_fifo_vacancy(drvdata);
			retries++;
			if (retries > XHI_MAX_RETRIES)
				return -EIO;
		}

		/*
		 * Write data into the Write FIFO.
		 */
		while ((write_fifo_vacancy != 0) &&
				(remaining_words > 0)) {
			fifo_icap_fifo_write(drvdata, *frame_buffer);

			remaining_words--;
			write_fifo_vacancy--;
			frame_buffer++;
		}
		/* Start pushing whatever is in the FIFO into the ICAP. */
		fifo_icap_start_config(drvdata);
	}

	/* Wait until the write has finished. */
	while (fifo_icap_busy(drvdata)) {
		retries++;
		if (retries > XHI_MAX_RETRIES)
			break;
	}

	dev_dbg(drvdata->dev, "done fifo_set_configuration\n");

	/*
	 * If the requested number of words have not been read from
	 * the device then indicate failure.
	 */
	if (remaining_words != 0)
		return -EIO;

	return 0;
}

/**
 * fifo_icap_get_configuration - Read configuration data from the device.
 * @drvdata: a pointer to the drvdata.
 * @data: Address of the data representing the partial bitstream
 * @size: the size of the partial bitstream in 32 bit words.
 *
 * This function reads the specified number of words from the ICAP device in
 * the polled mode.
 */
int fifo_icap_get_configuration(struct hwicap_drvdata *drvdata,
		u32 *frame_buffer, u32 num_words)
{

	u32 read_fifo_occupancy = 0;
	u32 retries = 0;
	u32 *data = frame_buffer;
	u32 remaining_words;
	u32 words_to_read;

	dev_dbg(drvdata->dev, "fifo_get_configuration\n");

	/*
	 * Check if the ICAP device is Busy with the last Write/Read
	 */
	if (fifo_icap_busy(drvdata))
		return -EBUSY;

	remaining_words = num_words;

	while (remaining_words > 0) {
		words_to_read = remaining_words;
		/* The hardware has a limit on the number of words
		   that can be read at one time.  */
		if (words_to_read > XHI_MAX_READ_TRANSACTION_WORDS)
			words_to_read = XHI_MAX_READ_TRANSACTION_WORDS;

		remaining_words -= words_to_read;

		fifo_icap_set_read_size(drvdata, words_to_read);
		fifo_icap_start_readback(drvdata);

		while (words_to_read > 0) {
			/* Wait until we have some data in the fifo. */
			while (read_fifo_occupancy == 0) {
				read_fifo_occupancy =
					fifo_icap_read_fifo_occupancy(drvdata);
				retries++;
				if (retries > XHI_MAX_RETRIES)
					return -EIO;
			}

			if (read_fifo_occupancy > words_to_read)
				read_fifo_occupancy = words_to_read;

			words_to_read -= read_fifo_occupancy;

			/* Read the data from the Read FIFO. */
			while (read_fifo_occupancy != 0) {
				*data++ = fifo_icap_fifo_read(drvdata);
				read_fifo_occupancy--;
			}
		}
	}

	dev_dbg(drvdata->dev, "done fifo_get_configuration\n");

	return 0;
}

/**
 * buffer_icap_reset - Reset the logic of the icap device.
 * @drvdata: a pointer to the drvdata.
 *
 * This function forces the software reset of the complete HWICAP device.
 * All the registers will return to the default value and the FIFO is also
 * flushed as a part of this software reset.
 */
void fifo_icap_reset(struct hwicap_drvdata *drvdata)
{
	u32 reg_data;
	/*
	 * Reset the device by setting/clearing the RESET bit in the
	 * Control Register.
	 */
	reg_data = in_be32(drvdata->base_address + XHI_CR_OFFSET);

	out_be32(drvdata->base_address + XHI_CR_OFFSET,
				reg_data | XHI_CR_SW_RESET_MASK);

	out_be32(drvdata->base_address + XHI_CR_OFFSET,
				reg_data & (~XHI_CR_SW_RESET_MASK));

}

/**
 * fifo_icap_flush_fifo - This function flushes the FIFOs in the device.
 * @drvdata: a pointer to the drvdata.
 */
void fifo_icap_flush_fifo(struct hwicap_drvdata *drvdata)
{
	u32 reg_data;
	/*
	 * Flush the FIFO by setting/clearing the FIFO Clear bit in the
	 * Control Register.
	 */
	reg_data = in_be32(drvdata->base_address + XHI_CR_OFFSET);

	out_be32(drvdata->base_address + XHI_CR_OFFSET,
				reg_data | XHI_CR_FIFO_CLR_MASK);

	out_be32(drvdata->base_address + XHI_CR_OFFSET,
				reg_data & (~XHI_CR_FIFO_CLR_MASK));
}