File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/scsi/aic7xxx/aic7xxx_93cx6.c b/drivers/scsi/aic7xxx/aic7xxx_93cx6.c
new file mode 100644
index 0000000..9e85a7e
--- /dev/null
+++ b/drivers/scsi/aic7xxx/aic7xxx_93cx6.c
@@ -0,0 +1,324 @@
+/*
+ * Interface for the 93C66/56/46/26/06 serial eeprom parts.
+ *
+ * Copyright (c) 1995, 1996 Daniel M. Eischen
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL").
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $Id: //depot/aic7xxx/aic7xxx/aic7xxx_93cx6.c#19 $
+ */
+
+/*
+ *   The instruction set of the 93C66/56/46/26/06 chips are as follows:
+ *
+ *               Start  OP	    *
+ *     Function   Bit  Code  Address**  Data     Description
+ *     -------------------------------------------------------------------
+ *     READ        1    10   A5 - A0             Reads data stored in memory,
+ *                                               starting at specified address
+ *     EWEN        1    00   11XXXX              Write enable must precede
+ *                                               all programming modes
+ *     ERASE       1    11   A5 - A0             Erase register A5A4A3A2A1A0
+ *     WRITE       1    01   A5 - A0   D15 - D0  Writes register
+ *     ERAL        1    00   10XXXX              Erase all registers
+ *     WRAL        1    00   01XXXX    D15 - D0  Writes to all registers
+ *     EWDS        1    00   00XXXX              Disables all programming
+ *                                               instructions
+ *     *Note: A value of X for address is a don't care condition.
+ *    **Note: There are 8 address bits for the 93C56/66 chips unlike
+ *	      the 93C46/26/06 chips which have 6 address bits.
+ *
+ *   The 93C46 has a four wire interface: clock, chip select, data in, and
+ *   data out.  In order to perform one of the above functions, you need
+ *   to enable the chip select for a clock period (typically a minimum of
+ *   1 usec, with the clock high and low a minimum of 750 and 250 nsec
+ *   respectively).  While the chip select remains high, you can clock in
+ *   the instructions (above) starting with the start bit, followed by the
+ *   OP code, Address, and Data (if needed).  For the READ instruction, the
+ *   requested 16-bit register contents is read from the data out line but
+ *   is preceded by an initial zero (leading 0, followed by 16-bits, MSB
+ *   first).  The clock cycling from low to high initiates the next data
+ *   bit to be sent from the chip.
+ */
+
+#ifdef __linux__
+#include "aic7xxx_osm.h"
+#include "aic7xxx_inline.h"
+#include "aic7xxx_93cx6.h"
+#else
+#include <dev/aic7xxx/aic7xxx_osm.h>
+#include <dev/aic7xxx/aic7xxx_inline.h>
+#include <dev/aic7xxx/aic7xxx_93cx6.h>
+#endif
+
+/*
+ * Right now, we only have to read the SEEPROM.  But we make it easier to
+ * add other 93Cx6 functions.
+ */
+struct seeprom_cmd {
+  	uint8_t len;
+ 	uint8_t bits[11];
+};
+
+/* Short opcodes for the c46 */
+static const struct seeprom_cmd seeprom_ewen = {9, {1, 0, 0, 1, 1, 0, 0, 0, 0}};
+static const struct seeprom_cmd seeprom_ewds = {9, {1, 0, 0, 0, 0, 0, 0, 0, 0}};
+
+/* Long opcodes for the C56/C66 */
+static const struct seeprom_cmd seeprom_long_ewen = {11, {1, 0, 0, 1, 1, 0, 0, 0, 0}};
+static const struct seeprom_cmd seeprom_long_ewds = {11, {1, 0, 0, 0, 0, 0, 0, 0, 0}};
+
+/* Common opcodes */
+static const struct seeprom_cmd seeprom_write = {3, {1, 0, 1}};
+static const struct seeprom_cmd seeprom_read  = {3, {1, 1, 0}};
+
+/*
+ * Wait for the SEERDY to go high; about 800 ns.
+ */
+#define CLOCK_PULSE(sd, rdy)				\
+	while ((SEEPROM_STATUS_INB(sd) & rdy) == 0) {	\
+		;  /* Do nothing */			\
+	}						\
+	(void)SEEPROM_INB(sd);	/* Clear clock */
+
+/*
+ * Send a START condition and the given command
+ */
+static void
+send_seeprom_cmd(struct seeprom_descriptor *sd, const struct seeprom_cmd *cmd)
+{
+	uint8_t temp;
+	int i = 0;
+
+	/* Send chip select for one clock cycle. */
+	temp = sd->sd_MS ^ sd->sd_CS;
+	SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+	CLOCK_PULSE(sd, sd->sd_RDY);
+
+	for (i = 0; i < cmd->len; i++) {
+		if (cmd->bits[i] != 0)
+			temp ^= sd->sd_DO;
+		SEEPROM_OUTB(sd, temp);
+		CLOCK_PULSE(sd, sd->sd_RDY);
+		SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+		CLOCK_PULSE(sd, sd->sd_RDY);
+		if (cmd->bits[i] != 0)
+			temp ^= sd->sd_DO;
+	}
+}
+
+/*
+ * Clear CS put the chip in the reset state, where it can wait for new commands.
+ */
+static void
+reset_seeprom(struct seeprom_descriptor *sd)
+{
+	uint8_t temp;
+
+	temp = sd->sd_MS;
+	SEEPROM_OUTB(sd, temp);
+	CLOCK_PULSE(sd, sd->sd_RDY);
+	SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+	CLOCK_PULSE(sd, sd->sd_RDY);
+	SEEPROM_OUTB(sd, temp);
+	CLOCK_PULSE(sd, sd->sd_RDY);
+}
+
+/*
+ * Read the serial EEPROM and returns 1 if successful and 0 if
+ * not successful.
+ */
+int
+ahc_read_seeprom(struct seeprom_descriptor *sd, uint16_t *buf,
+		 u_int start_addr, u_int count)
+{
+	int i = 0;
+	u_int k = 0;
+	uint16_t v;
+	uint8_t temp;
+
+	/*
+	 * Read the requested registers of the seeprom.  The loop
+	 * will range from 0 to count-1.
+	 */
+	for (k = start_addr; k < count + start_addr; k++) {
+		/*
+		 * Now we're ready to send the read command followed by the
+		 * address of the 16-bit register we want to read.
+		 */
+		send_seeprom_cmd(sd, &seeprom_read);
+
+		/* Send the 6 or 8 bit address (MSB first, LSB last). */
+		temp = sd->sd_MS ^ sd->sd_CS;
+		for (i = (sd->sd_chip - 1); i >= 0; i--) {
+			if ((k & (1 << i)) != 0)
+				temp ^= sd->sd_DO;
+			SEEPROM_OUTB(sd, temp);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			if ((k & (1 << i)) != 0)
+				temp ^= sd->sd_DO;
+		}
+
+		/*
+		 * Now read the 16 bit register.  An initial 0 precedes the
+		 * register contents which begins with bit 15 (MSB) and ends
+		 * with bit 0 (LSB).  The initial 0 will be shifted off the
+		 * top of our word as we let the loop run from 0 to 16.
+		 */
+		v = 0;
+		for (i = 16; i >= 0; i--) {
+			SEEPROM_OUTB(sd, temp);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			v <<= 1;
+			if (SEEPROM_DATA_INB(sd) & sd->sd_DI)
+				v |= 1;
+			SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+		}
+
+		buf[k - start_addr] = v;
+
+		/* Reset the chip select for the next command cycle. */
+		reset_seeprom(sd);
+	}
+#ifdef AHC_DUMP_EEPROM
+	printk("\nSerial EEPROM:\n\t");
+	for (k = 0; k < count; k = k + 1) {
+		if (((k % 8) == 0) && (k != 0)) {
+			printk(KERN_CONT "\n\t");
+		}
+		printk(KERN_CONT " 0x%x", buf[k]);
+	}
+	printk(KERN_CONT "\n");
+#endif
+	return (1);
+}
+
+/*
+ * Write the serial EEPROM and return 1 if successful and 0 if
+ * not successful.
+ */
+int
+ahc_write_seeprom(struct seeprom_descriptor *sd, uint16_t *buf,
+		  u_int start_addr, u_int count)
+{
+	const struct seeprom_cmd *ewen, *ewds;
+	uint16_t v;
+	uint8_t temp;
+	int i, k;
+
+	/* Place the chip into write-enable mode */
+	if (sd->sd_chip == C46) {
+		ewen = &seeprom_ewen;
+		ewds = &seeprom_ewds;
+	} else if (sd->sd_chip == C56_66) {
+		ewen = &seeprom_long_ewen;
+		ewds = &seeprom_long_ewds;
+	} else {
+		printk("ahc_write_seeprom: unsupported seeprom type %d\n",
+		       sd->sd_chip);
+		return (0);
+	}
+
+	send_seeprom_cmd(sd, ewen);
+	reset_seeprom(sd);
+
+	/* Write all requested data out to the seeprom. */
+	temp = sd->sd_MS ^ sd->sd_CS;
+	for (k = start_addr; k < count + start_addr; k++) {
+		/* Send the write command */
+		send_seeprom_cmd(sd, &seeprom_write);
+
+		/* Send the 6 or 8 bit address (MSB first). */
+		for (i = (sd->sd_chip - 1); i >= 0; i--) {
+			if ((k & (1 << i)) != 0)
+				temp ^= sd->sd_DO;
+			SEEPROM_OUTB(sd, temp);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			if ((k & (1 << i)) != 0)
+				temp ^= sd->sd_DO;
+		}
+
+		/* Write the 16 bit value, MSB first */
+		v = buf[k - start_addr];
+		for (i = 15; i >= 0; i--) {
+			if ((v & (1 << i)) != 0)
+				temp ^= sd->sd_DO;
+			SEEPROM_OUTB(sd, temp);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			if ((v & (1 << i)) != 0)
+				temp ^= sd->sd_DO;
+		}
+
+		/* Wait for the chip to complete the write */
+		temp = sd->sd_MS;
+		SEEPROM_OUTB(sd, temp);
+		CLOCK_PULSE(sd, sd->sd_RDY);
+		temp = sd->sd_MS ^ sd->sd_CS;
+		do {
+			SEEPROM_OUTB(sd, temp);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+			SEEPROM_OUTB(sd, temp ^ sd->sd_CK);
+			CLOCK_PULSE(sd, sd->sd_RDY);
+		} while ((SEEPROM_DATA_INB(sd) & sd->sd_DI) == 0);
+
+		reset_seeprom(sd);
+	}
+
+	/* Put the chip back into write-protect mode */
+	send_seeprom_cmd(sd, ewds);
+	reset_seeprom(sd);
+
+	return (1);
+}
+
+int
+ahc_verify_cksum(struct seeprom_config *sc)
+{
+	int i;
+	int maxaddr;
+	uint32_t checksum;
+	uint16_t *scarray;
+
+	maxaddr = (sizeof(*sc)/2) - 1;
+	checksum = 0;
+	scarray = (uint16_t *)sc;
+
+	for (i = 0; i < maxaddr; i++)
+		checksum = checksum + scarray[i];
+	if (checksum == 0
+	 || (checksum & 0xFFFF) != sc->checksum) {
+		return (0);
+	} else {
+		return(1);
+	}
+}