drivers/spi/ich.c

/*
 * Copyright (c) 2011-12 The Chromium OS Authors.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 *
 * This file is derived from the flashrom project.
 */

#include <common.h>
#include <errno.h>
#include <malloc.h>
#include <spi.h>
#include <pci.h>
#include <pci_ids.h>
#include <asm/io.h>

#include "ich.h"

#define SPI_OPCODE_WREN      0x06
#define SPI_OPCODE_FAST_READ 0x0b

struct ich_ctlr {
	pci_dev_t dev;		/* PCI device number */
	int ich_version;	/* Controller version, 7 or 9 */
	bool use_sbase;		/* Use SBASE instead of RCB */
	int ichspi_lock;
	int locked;
	uint8_t *opmenu;
	int menubytes;
	void *base;		/* Base of register set */
	uint16_t *preop;
	uint16_t *optype;
	uint32_t *addr;
	uint8_t *data;
	unsigned databytes;
	uint8_t *status;
	uint16_t *control;
	uint32_t *bbar;
	uint32_t *pr;		/* only for ich9 */
	uint8_t *speed;		/* pointer to speed control */
	ulong max_speed;	/* Maximum bus speed in MHz */
};

struct ich_ctlr ctlr;

static inline struct ich_spi_slave *to_ich_spi(struct spi_slave *slave)
{
	return container_of(slave, struct ich_spi_slave, slave);
}

static unsigned int ich_reg(const void *addr)
{
	return (unsigned)(addr - ctlr.base) & 0xffff;
}

static u8 ich_readb(const void *addr)
{
	u8 value = readb(addr);

	debug("read %2.2x from %4.4x\n", value, ich_reg(addr));

	return value;
}

static u16 ich_readw(const void *addr)
{
	u16 value = readw(addr);

	debug("read %4.4x from %4.4x\n", value, ich_reg(addr));

	return value;
}

static u32 ich_readl(const void *addr)
{
	u32 value = readl(addr);

	debug("read %8.8x from %4.4x\n", value, ich_reg(addr));

	return value;
}

static void ich_writeb(u8 value, void *addr)
{
	writeb(value, addr);
	debug("wrote %2.2x to %4.4x\n", value, ich_reg(addr));
}

static void ich_writew(u16 value, void *addr)
{
	writew(value, addr);
	debug("wrote %4.4x to %4.4x\n", value, ich_reg(addr));
}

static void ich_writel(u32 value, void *addr)
{
	writel(value, addr);
	debug("wrote %8.8x to %4.4x\n", value, ich_reg(addr));
}

static void write_reg(const void *value, void *dest, uint32_t size)
{
	memcpy_toio(dest, value, size);
}

static void read_reg(const void *src, void *value, uint32_t size)
{
	memcpy_fromio(value, src, size);
}

static void ich_set_bbar(struct ich_ctlr *ctlr, uint32_t minaddr)
{
	const uint32_t bbar_mask = 0x00ffff00;
	uint32_t ichspi_bbar;

	minaddr &= bbar_mask;
	ichspi_bbar = ich_readl(ctlr->bbar) & ~bbar_mask;
	ichspi_bbar |= minaddr;
	ich_writel(ichspi_bbar, ctlr->bbar);
}

int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
	puts("spi_cs_is_valid used but not implemented\n");
	return 0;
}

struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
		unsigned int max_hz, unsigned int mode)
{
	struct ich_spi_slave *ich;

	ich = spi_alloc_slave(struct ich_spi_slave, bus, cs);
	if (!ich) {
		puts("ICH SPI: Out of memory\n");
		return NULL;
	}

	/*
	 * Yes this controller can only write a small number of bytes at
	 * once! The limit is typically 64 bytes.
	 */
	ich->slave.max_write_size = ctlr.databytes;
	ich->speed = max_hz;

	/*
	 * ICH 7 SPI controller only supports array read command
	 * and byte program command for SST flash
	 */
	if (ctlr.ich_version == 7 || ctlr.use_sbase) {
		ich->slave.op_mode_rx = SPI_OPM_RX_AS;
		ich->slave.op_mode_tx = SPI_OPM_TX_BP;
	}

	return &ich->slave;
}

struct spi_slave *spi_setup_slave_fdt(const void *blob, int slave_node,
				      int spi_node)
{
	/* We only support a single SPI at present */
	return spi_setup_slave(0, 0, 20000000, 0);
}

void spi_free_slave(struct spi_slave *slave)
{
	struct ich_spi_slave *ich = to_ich_spi(slave);

	free(ich);
}

/*
 * Check if this device ID matches one of supported Intel PCH devices.
 *
 * Return the ICH version if there is a match, or zero otherwise.
 */
static int get_ich_version(uint16_t device_id)
{
	if (device_id == PCI_DEVICE_ID_INTEL_TGP_LPC ||
	    device_id == PCI_DEVICE_ID_INTEL_ITC_LPC ||
	    device_id == PCI_DEVICE_ID_INTEL_QRK_ILB)
		return 7;

	if ((device_id >= PCI_DEVICE_ID_INTEL_COUGARPOINT_LPC_MIN &&
	     device_id <= PCI_DEVICE_ID_INTEL_COUGARPOINT_LPC_MAX) ||
	    (device_id >= PCI_DEVICE_ID_INTEL_PANTHERPOINT_LPC_MIN &&
	     device_id <= PCI_DEVICE_ID_INTEL_PANTHERPOINT_LPC_MAX) ||
	    device_id == PCI_DEVICE_ID_INTEL_VALLEYVIEW_LPC ||
	    device_id == PCI_DEVICE_ID_INTEL_LYNXPOINT_LPC)
		return 9;

	return 0;
}

/* @return 1 if the SPI flash supports the 33MHz speed */
static int ich9_can_do_33mhz(pci_dev_t dev)
{
	u32 fdod, speed;

	/* Observe SPI Descriptor Component Section 0 */
	pci_write_config_dword(dev, 0xb0, 0x1000);

	/* Extract the Write/Erase SPI Frequency from descriptor */
	pci_read_config_dword(dev, 0xb4, &fdod);

	/* Bits 23:21 have the fast read clock frequency, 0=20MHz, 1=33MHz */
	speed = (fdod >> 21) & 7;

	return speed == 1;
}

static int ich_find_spi_controller(struct ich_ctlr *ich)
{
	int last_bus = pci_last_busno();
	int bus;

	if (last_bus == -1) {
		debug("No PCI busses?\n");
		return -ENODEV;
	}

	for (bus = 0; bus <= last_bus; bus++) {
		uint16_t vendor_id, device_id;
		uint32_t ids;
		pci_dev_t dev;

		dev = PCI_BDF(bus, 31, 0);
		pci_read_config_dword(dev, 0, &ids);
		vendor_id = ids;
		device_id = ids >> 16;

		if (vendor_id == PCI_VENDOR_ID_INTEL) {
			ich->dev = dev;
			ich->ich_version = get_ich_version(device_id);
			if (device_id == PCI_DEVICE_ID_INTEL_VALLEYVIEW_LPC)
				ich->use_sbase = true;
			return ich->ich_version == 0 ? -ENODEV : 0;
		}
	}

	debug("ICH SPI: No ICH found.\n");
	return -ENODEV;
}

static int ich_init_controller(struct ich_ctlr *ctlr)
{
	uint8_t *rcrb; /* Root Complex Register Block */
	uint32_t rcba; /* Root Complex Base Address */
	uint32_t sbase_addr;
	uint8_t *sbase;

	pci_read_config_dword(ctlr->dev, 0xf0, &rcba);
	/* Bits 31-14 are the base address, 13-1 are reserved, 0 is enable. */
	rcrb = (uint8_t *)(rcba & 0xffffc000);

	/* SBASE is similar */
	pci_read_config_dword(ctlr->dev, 0x54, &sbase_addr);
	sbase = (uint8_t *)(sbase_addr & 0xfffffe00);

	if (ctlr->ich_version == 7) {
		struct ich7_spi_regs *ich7_spi;

		ich7_spi = (struct ich7_spi_regs *)(rcrb + 0x3020);
		ctlr->ichspi_lock = ich_readw(&ich7_spi->spis) & SPIS_LOCK;
		ctlr->opmenu = ich7_spi->opmenu;
		ctlr->menubytes = sizeof(ich7_spi->opmenu);
		ctlr->optype = &ich7_spi->optype;
		ctlr->addr = &ich7_spi->spia;
		ctlr->data = (uint8_t *)ich7_spi->spid;
		ctlr->databytes = sizeof(ich7_spi->spid);
		ctlr->status = (uint8_t *)&ich7_spi->spis;
		ctlr->control = &ich7_spi->spic;
		ctlr->bbar = &ich7_spi->bbar;
		ctlr->preop = &ich7_spi->preop;
		ctlr->base = ich7_spi;
	} else if (ctlr->ich_version == 9) {
		struct ich9_spi_regs *ich9_spi;

		if (ctlr->use_sbase)
			ich9_spi = (struct ich9_spi_regs *)sbase;
		else
			ich9_spi = (struct ich9_spi_regs *)(rcrb + 0x3800);
		ctlr->ichspi_lock = ich_readw(&ich9_spi->hsfs) & HSFS_FLOCKDN;
		ctlr->opmenu = ich9_spi->opmenu;
		ctlr->menubytes = sizeof(ich9_spi->opmenu);
		ctlr->optype = &ich9_spi->optype;
		ctlr->addr = &ich9_spi->faddr;
		ctlr->data = (uint8_t *)ich9_spi->fdata;
		ctlr->databytes = sizeof(ich9_spi->fdata);
		ctlr->status = &ich9_spi->ssfs;
		ctlr->control = (uint16_t *)ich9_spi->ssfc;
		ctlr->speed = ich9_spi->ssfc + 2;
		ctlr->bbar = &ich9_spi->bbar;
		ctlr->preop = &ich9_spi->preop;
		ctlr->pr = &ich9_spi->pr[0];
		ctlr->base = ich9_spi;
	} else {
		debug("ICH SPI: Unrecognized ICH version %d.\n",
		      ctlr->ich_version);
		return -1;
	}

	/* Work out the maximum speed we can support */
	ctlr->max_speed = 20000000;
	if (ctlr->ich_version == 9 && ich9_can_do_33mhz(ctlr->dev))
		ctlr->max_speed = 33000000;
	debug("ICH SPI: Version %d detected at %p, speed %ld\n",
	      ctlr->ich_version, ctlr->base, ctlr->max_speed);

	ich_set_bbar(ctlr, 0);

	return 0;
}

void spi_init(void)
{
	uint8_t bios_cntl;

	if (ich_find_spi_controller(&ctlr)) {
		printf("ICH SPI: Cannot find device\n");
		return;
	}

	if (ich_init_controller(&ctlr)) {
		printf("ICH SPI: Cannot setup controller\n");
		return;
	}

	/*
	 * Disable the BIOS write protect so write commands are allowed.  On
	 * v9, deassert SMM BIOS Write Protect Disable.
	 */
	if (ctlr.use_sbase) {
		struct ich9_spi_regs *ich9_spi;

		ich9_spi = (struct ich9_spi_regs *)ctlr.base;
		bios_cntl = ich_readb(&ich9_spi->bcr);
		bios_cntl &= ~(1 << 5);	/* clear Enable InSMM_STS (EISS) */
		bios_cntl |= 1;		/* Write Protect Disable (WPD) */
		ich_writeb(bios_cntl, &ich9_spi->bcr);
	} else {
		pci_read_config_byte(ctlr.dev, 0xdc, &bios_cntl);
		if (ctlr.ich_version == 9)
			bios_cntl &= ~(1 << 5);
		pci_write_config_byte(ctlr.dev, 0xdc, bios_cntl | 0x1);
	}
}

int spi_claim_bus(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
	return 0;
}

void spi_release_bus(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
}

void spi_cs_activate(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
}

void spi_cs_deactivate(struct spi_slave *slave)
{
	/* Handled by ICH automatically. */
}

static inline void spi_use_out(struct spi_trans *trans, unsigned bytes)
{
	trans->out += bytes;
	trans->bytesout -= bytes;
}

static inline void spi_use_in(struct spi_trans *trans, unsigned bytes)
{
	trans->in += bytes;
	trans->bytesin -= bytes;
}

static void spi_setup_type(struct spi_trans *trans, int data_bytes)
{
	trans->type = 0xFF;

	/* Try to guess spi type from read/write sizes. */
	if (trans->bytesin == 0) {
		if (trans->bytesout + data_bytes > 4)
			/*
			 * If bytesin = 0 and bytesout > 4, we presume this is
			 * a write data operation, which is accompanied by an
			 * address.
			 */
			trans->type = SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS;
		else
			trans->type = SPI_OPCODE_TYPE_WRITE_NO_ADDRESS;
		return;
	}

	if (trans->bytesout == 1) {	/* and bytesin is > 0 */
		trans->type = SPI_OPCODE_TYPE_READ_NO_ADDRESS;
		return;
	}

	if (trans->bytesout == 4)	/* and bytesin is > 0 */
		trans->type = SPI_OPCODE_TYPE_READ_WITH_ADDRESS;

	/* Fast read command is called with 5 bytes instead of 4 */
	if (trans->out[0] == SPI_OPCODE_FAST_READ && trans->bytesout == 5) {
		trans->type = SPI_OPCODE_TYPE_READ_WITH_ADDRESS;
		--trans->bytesout;
	}
}

static int spi_setup_opcode(struct spi_trans *trans)
{
	uint16_t optypes;
	uint8_t opmenu[ctlr.menubytes];

	trans->opcode = trans->out[0];
	spi_use_out(trans, 1);
	if (!ctlr.ichspi_lock) {
		/* The lock is off, so just use index 0. */
		ich_writeb(trans->opcode, ctlr.opmenu);
		optypes = ich_readw(ctlr.optype);
		optypes = (optypes & 0xfffc) | (trans->type & 0x3);
		ich_writew(optypes, ctlr.optype);
		return 0;
	} else {
		/* The lock is on. See if what we need is on the menu. */
		uint8_t optype;
		uint16_t opcode_index;

		/* Write Enable is handled as atomic prefix */
		if (trans->opcode == SPI_OPCODE_WREN)
			return 0;

		read_reg(ctlr.opmenu, opmenu, sizeof(opmenu));
		for (opcode_index = 0; opcode_index < ctlr.menubytes;
				opcode_index++) {
			if (opmenu[opcode_index] == trans->opcode)
				break;
		}

		if (opcode_index == ctlr.menubytes) {
			printf("ICH SPI: Opcode %x not found\n",
			       trans->opcode);
			return -1;
		}

		optypes = ich_readw(ctlr.optype);
		optype = (optypes >> (opcode_index * 2)) & 0x3;
		if (trans->type == SPI_OPCODE_TYPE_WRITE_NO_ADDRESS &&
		    optype == SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS &&
		    trans->bytesout >= 3) {
			/* We guessed wrong earlier. Fix it up. */
			trans->type = optype;
		}
		if (optype != trans->type) {
			printf("ICH SPI: Transaction doesn't fit type %d\n",
			       optype);
			return -1;
		}
		return opcode_index;
	}
}

static int spi_setup_offset(struct spi_trans *trans)
{
	/* Separate the SPI address and data. */
	switch (trans->type) {
	case SPI_OPCODE_TYPE_READ_NO_ADDRESS:
	case SPI_OPCODE_TYPE_WRITE_NO_ADDRESS:
		return 0;
	case SPI_OPCODE_TYPE_READ_WITH_ADDRESS:
	case SPI_OPCODE_TYPE_WRITE_WITH_ADDRESS:
		trans->offset = ((uint32_t)trans->out[0] << 16) |
				((uint32_t)trans->out[1] << 8) |
				((uint32_t)trans->out[2] << 0);
		spi_use_out(trans, 3);
		return 1;
	default:
		printf("Unrecognized SPI transaction type %#x\n", trans->type);
		return -1;
	}
}

/*
 * Wait for up to 6s til status register bit(s) turn 1 (in case wait_til_set
 * below is true) or 0. In case the wait was for the bit(s) to set - write
 * those bits back, which would cause resetting them.
 *
 * Return the last read status value on success or -1 on failure.
 */
static int ich_status_poll(u16 bitmask, int wait_til_set)
{
	int timeout = 600000; /* This will result in 6s */
	u16 status = 0;

	while (timeout--) {
		status = ich_readw(ctlr.status);
		if (wait_til_set ^ ((status & bitmask) == 0)) {
			if (wait_til_set)
				ich_writew((status & bitmask), ctlr.status);
			return status;
		}
		udelay(10);
	}

	printf("ICH SPI: SCIP timeout, read %x, expected %x\n",
	       status, bitmask);
	return -1;
}

/*
int spi_xfer(struct spi_slave *slave, const void *dout,
		unsigned int bitsout, void *din, unsigned int bitsin)
*/
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
		void *din, unsigned long flags)
{
	struct ich_spi_slave *ich = to_ich_spi(slave);
	uint16_t control;
	int16_t opcode_index;
	int with_address;
	int status;
	int bytes = bitlen / 8;
	struct spi_trans *trans = &ich->trans;
	unsigned type = flags & (SPI_XFER_BEGIN | SPI_XFER_END);
	int using_cmd = 0;

	/* Ee don't support writing partial bytes. */
	if (bitlen % 8) {
		debug("ICH SPI: Accessing partial bytes not supported\n");
		return -1;
	}

	/* An empty end transaction can be ignored */
	if (type == SPI_XFER_END && !dout && !din)
		return 0;

	if (type & SPI_XFER_BEGIN)
		memset(trans, '\0', sizeof(*trans));

	/* Dp we need to come back later to finish it? */
	if (dout && type == SPI_XFER_BEGIN) {
		if (bytes > ICH_MAX_CMD_LEN) {
			debug("ICH SPI: Command length limit exceeded\n");
			return -1;
		}
		memcpy(trans->cmd, dout, bytes);
		trans->cmd_len = bytes;
		debug("ICH SPI: Saved %d bytes\n", bytes);
		return 0;
	}

	/*
	 * We process a 'middle' spi_xfer() call, which has no
	 * SPI_XFER_BEGIN/END, as an independent transaction as if it had
	 * an end. We therefore repeat the command. This is because ICH
	 * seems to have no support for this, or because interest (in digging
	 * out the details and creating a special case in the code) is low.
	 */
	if (trans->cmd_len) {
		trans->out = trans->cmd;
		trans->bytesout = trans->cmd_len;
		using_cmd = 1;
		debug("ICH SPI: Using %d bytes\n", trans->cmd_len);
	} else {
		trans->out = dout;
		trans->bytesout = dout ? bytes : 0;
	}

	trans->in = din;
	trans->bytesin = din ? bytes : 0;

	/* There has to always at least be an opcode. */
	if (!trans->bytesout) {
		debug("ICH SPI: No opcode for transfer\n");
		return -1;
	}

	if (ich_status_poll(SPIS_SCIP, 0) == -1)
		return -1;

	ich_writew(SPIS_CDS | SPIS_FCERR, ctlr.status);

	spi_setup_type(trans, using_cmd ? bytes : 0);
	opcode_index = spi_setup_opcode(trans);
	if (opcode_index < 0)
		return -1;
	with_address = spi_setup_offset(trans);
	if (with_address < 0)
		return -1;

	if (trans->opcode == SPI_OPCODE_WREN) {
		/*
		 * Treat Write Enable as Atomic Pre-Op if possible
		 * in order to prevent the Management Engine from
		 * issuing a transaction between WREN and DATA.
		 */
		if (!ctlr.ichspi_lock)
			ich_writew(trans->opcode, ctlr.preop);
		return 0;
	}

	if (ctlr.speed && ctlr.max_speed >= 33000000) {
		int byte;

		byte = ich_readb(ctlr.speed);
		if (ich->speed >= 33000000)
			byte |= SSFC_SCF_33MHZ;
		else
			byte &= ~SSFC_SCF_33MHZ;
		ich_writeb(byte, ctlr.speed);
	}

	/* See if we have used up the command data */
	if (using_cmd && dout && bytes) {
		trans->out = dout;
		trans->bytesout = bytes;
		debug("ICH SPI: Moving to data, %d bytes\n", bytes);
	}

	/* Preset control fields */
	control = ich_readw(ctlr.control);
	control &= ~SSFC_RESERVED;
	control = SPIC_SCGO | ((opcode_index & 0x07) << 4);

	/* Issue atomic preop cycle if needed */
	if (ich_readw(ctlr.preop))
		control |= SPIC_ACS;

	if (!trans->bytesout && !trans->bytesin) {
		/* SPI addresses are 24 bit only */
		if (with_address)
			ich_writel(trans->offset & 0x00FFFFFF, ctlr.addr);

		/*
		 * This is a 'no data' command (like Write Enable), its
		 * bitesout size was 1, decremented to zero while executing
		 * spi_setup_opcode() above. Tell the chip to send the
		 * command.
		 */
		ich_writew(control, ctlr.control);

		/* wait for the result */
		status = ich_status_poll(SPIS_CDS | SPIS_FCERR, 1);
		if (status == -1)
			return -1;

		if (status & SPIS_FCERR) {
			debug("ICH SPI: Command transaction error\n");
			return -1;
		}

		return 0;
	}

	/*
	 * Check if this is a write command atempting to transfer more bytes
	 * than the controller can handle. Iterations for writes are not
	 * supported here because each SPI write command needs to be preceded
	 * and followed by other SPI commands, and this sequence is controlled
	 * by the SPI chip driver.
	 */
	if (trans->bytesout > ctlr.databytes) {
		debug("ICH SPI: Too much to write. This should be prevented by the driver's max_write_size?\n");
		return -1;
	}

	/*
	 * Read or write up to databytes bytes at a time until everything has
	 * been sent.
	 */
	while (trans->bytesout || trans->bytesin) {
		uint32_t data_length;

		/* SPI addresses are 24 bit only */
		ich_writel(trans->offset & 0x00FFFFFF, ctlr.addr);

		if (trans->bytesout)
			data_length = min(trans->bytesout, ctlr.databytes);
		else
			data_length = min(trans->bytesin, ctlr.databytes);

		/* Program data into FDATA0 to N */
		if (trans->bytesout) {
			write_reg(trans->out, ctlr.data, data_length);
			spi_use_out(trans, data_length);
			if (with_address)
				trans->offset += data_length;
		}

		/* Add proper control fields' values */
		control &= ~((ctlr.databytes - 1) << 8);
		control |= SPIC_DS;
		control |= (data_length - 1) << 8;

		/* write it */
		ich_writew(control, ctlr.control);

		/* Wait for Cycle Done Status or Flash Cycle Error. */
		status = ich_status_poll(SPIS_CDS | SPIS_FCERR, 1);
		if (status == -1)
			return -1;

		if (status & SPIS_FCERR) {
			debug("ICH SPI: Data transaction error\n");
			return -1;
		}

		if (trans->bytesin) {
			read_reg(ctlr.data, trans->in, data_length);
			spi_use_in(trans, data_length);
			if (with_address)
				trans->offset += data_length;
		}
	}

	/* Clear atomic preop now that xfer is done */
	ich_writew(0, ctlr.preop);

	return 0;
}


/*
 * This uses the SPI controller from the Intel Cougar Point and Panther Point
 * PCH to write-protect portions of the SPI flash until reboot. The changes
 * don't actually take effect until the HSFS[FLOCKDN] bit is set, but that's
 * done elsewhere.
 */
int spi_write_protect_region(uint32_t lower_limit, uint32_t length, int hint)
{
	uint32_t tmplong;
	uint32_t upper_limit;

	if (!ctlr.pr) {
		printf("%s: operation not supported on this chipset\n",
		       __func__);
		return -1;
	}

	if (length == 0 ||
	    lower_limit > (0xFFFFFFFFUL - length) + 1 ||
	    hint < 0 || hint > 4) {
		printf("%s(0x%x, 0x%x, %d): invalid args\n", __func__,
		       lower_limit, length, hint);
		return -1;
	}

	upper_limit = lower_limit + length - 1;

	/*
	 * Determine bits to write, as follows:
	 *  31     Write-protection enable (includes erase operation)
	 *  30:29  reserved
	 *  28:16  Upper Limit (FLA address bits 24:12, with 11:0 == 0xfff)
	 *  15     Read-protection enable
	 *  14:13  reserved
	 *  12:0   Lower Limit (FLA address bits 24:12, with 11:0 == 0x000)
	 */
	tmplong = 0x80000000 |
		((upper_limit & 0x01fff000) << 4) |
		((lower_limit & 0x01fff000) >> 12);

	printf("%s: writing 0x%08x to %p\n", __func__, tmplong,
	       &ctlr.pr[hint]);
	ctlr.pr[hint] = tmplong;

	return 0;
}