drivers/mtd/pic32_flash.c - platform/external/u-boot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (C) 2015
  * Cristian Birsan <cristian.birsan@microchip.com>
  * Purna Chandra Mandal <purna.mandal@microchip.com>
  */

 #include <common.h>
 #include <cpu_func.h>
 #include <dm.h>
 #include <fdt_support.h>
 #include <flash.h>
 #include <init.h>
 #include <irq_func.h>
 #include <asm/global_data.h>
 #include <linux/bitops.h>
 #include <mach/pic32.h>
 #include <wait_bit.h>

 DECLARE_GLOBAL_DATA_PTR;

 /* NVM Controller registers */
 struct pic32_reg_nvm {
 	struct pic32_reg_atomic ctrl;
 	struct pic32_reg_atomic key;
 	struct pic32_reg_atomic addr;
 	struct pic32_reg_atomic data;
 };

 /* NVM operations */
 #define NVMOP_NOP		0
 #define NVMOP_WORD_WRITE	1
 #define NVMOP_PAGE_ERASE	4

 /* NVM control bits */
 #define NVM_WR			BIT(15)
 #define NVM_WREN		BIT(14)
 #define NVM_WRERR		BIT(13)
 #define NVM_LVDERR		BIT(12)

 /* NVM programming unlock register */
 #define LOCK_KEY		0x0
 #define UNLOCK_KEY1		0xaa996655
 #define UNLOCK_KEY2		0x556699aa

 /*
  * PIC32 flash banks consist of number of pages, each page
  * into number of rows and rows into number of words.
  * Here we will maintain page information instead of sector.
  */
 flash_info_t flash_info[CONFIG_SYS_MAX_FLASH_BANKS];
 static struct pic32_reg_nvm *nvm_regs_p;

 static inline void flash_initiate_operation(u32 nvmop)
 {
 	/* set operation */
 	writel(nvmop, &nvm_regs_p->ctrl.raw);

 	/* enable flash write */
 	writel(NVM_WREN, &nvm_regs_p->ctrl.set);

 	/* unlock sequence */
 	writel(LOCK_KEY, &nvm_regs_p->key.raw);
 	writel(UNLOCK_KEY1, &nvm_regs_p->key.raw);
 	writel(UNLOCK_KEY2, &nvm_regs_p->key.raw);

 	/* initiate operation */
 	writel(NVM_WR, &nvm_regs_p->ctrl.set);
 }

 static int flash_wait_till_busy(const char *func, ulong timeout)
 {
 	int ret = wait_for_bit_le32(&nvm_regs_p->ctrl.raw,
 				    NVM_WR, false, timeout, false);

 	return ret ? ERR_TIMEOUT : ERR_OK;
 }

 static inline int flash_complete_operation(void)
 {
 	u32 tmp;

 	tmp = readl(&nvm_regs_p->ctrl.raw);
 	if (tmp & NVM_WRERR) {
 		printf("Error in Block Erase - Lock Bit may be set!\n");
 		flash_initiate_operation(NVMOP_NOP);
 		return ERR_PROTECTED;
 	}

 	if (tmp & NVM_LVDERR) {
 		printf("Error in Block Erase - low-vol detected!\n");
 		flash_initiate_operation(NVMOP_NOP);
 		return ERR_NOT_ERASED;
 	}

 	/* disable flash write or erase operation */
 	writel(NVM_WREN, &nvm_regs_p->ctrl.clr);

 	return ERR_OK;
 }

 /*
  * Erase flash sectors, returns:
  * ERR_OK - OK
  * ERR_INVAL - invalid sector arguments
  * ERR_TIMEOUT - write timeout
  * ERR_NOT_ERASED - Flash not erased
  * ERR_UNKNOWN_FLASH_VENDOR - incorrect flash
  */
 int flash_erase(flash_info_t *info, int s_first, int s_last)
 {
 	ulong sect_start, sect_end, flags;
 	int prot, sect;
 	int rc;

 	if ((info->flash_id & FLASH_VENDMASK) != FLASH_MAN_MCHP) {
 		printf("Can't erase unknown flash type %08lx - aborted\n",
 		       info->flash_id);
 		return ERR_UNKNOWN_FLASH_VENDOR;
 	}

 	if ((s_first < 0) || (s_first > s_last)) {
 		printf("- no sectors to erase\n");
 		return ERR_INVAL;
 	}

 	prot = 0;
 	for (sect = s_first; sect <= s_last; ++sect) {
 		if (info->protect[sect])
 			prot++;
 	}

 	if (prot)
 		printf("- Warning: %d protected sectors will not be erased!\n",
 		       prot);
 	else
 		printf("\n");

 	/* erase on unprotected sectors */
 	for (sect = s_first; sect <= s_last; sect++) {
 		if (info->protect[sect])
 			continue;

 		/* disable interrupts */
 		flags = disable_interrupts();

 		/* write destination page address (physical) */
 		sect_start = CPHYSADDR(info->start[sect]);
 		writel(sect_start, &nvm_regs_p->addr.raw);

 		/* page erase */
 		flash_initiate_operation(NVMOP_PAGE_ERASE);

 		/* wait */
 		rc = flash_wait_till_busy(__func__,
 					  CONFIG_SYS_FLASH_ERASE_TOUT);

 		/* re-enable interrupts if necessary */
 		if (flags)
 			enable_interrupts();

 		if (rc != ERR_OK)
 			return rc;

 		rc = flash_complete_operation();
 		if (rc != ERR_OK)
 			return rc;

 		/*
 		 * flash content is updated but cache might contain stale
 		 * data, so invalidate dcache.
 		 */
 		sect_end = info->start[sect] + info->size / info->sector_count;
 		invalidate_dcache_range(info->start[sect], sect_end);
 	}

 	printf(" done\n");
 	return ERR_OK;
 }

 int page_erase(flash_info_t *info, int sect)
 {
 	return 0;
 }

 /* Write a word to flash */
 static int write_word(flash_info_t *info, ulong dest, ulong word)
 {
 	ulong flags;
 	int rc;

 	/* read flash to check if it is sufficiently erased */
 	if ((readl((void __iomem *)dest) & word) != word) {
 		printf("Error, Flash not erased!\n");
 		return ERR_NOT_ERASED;
 	}

 	/* disable interrupts */
 	flags = disable_interrupts();

 	/* update destination page address (physical) */
 	writel(CPHYSADDR(dest), &nvm_regs_p->addr.raw);
 	writel(word, &nvm_regs_p->data.raw);

 	/* word write */
 	flash_initiate_operation(NVMOP_WORD_WRITE);

 	/* wait for operation to complete */
 	rc = flash_wait_till_busy(__func__, CONFIG_SYS_FLASH_WRITE_TOUT);

 	/* re-enable interrupts if necessary */
 	if (flags)
 		enable_interrupts();

 	if (rc != ERR_OK)
 		return rc;

 	return flash_complete_operation();
 }

 /*
  * Copy memory to flash, returns:
  * ERR_OK - OK
  * ERR_TIMEOUT - write timeout
  * ERR_NOT_ERASED - Flash not erased
  */
 int write_buff(flash_info_t *info, uchar *src, ulong addr, ulong cnt)
 {
 	ulong dst, tmp_le, len = cnt;
 	int i, l, rc;
 	uchar *cp;

 	/* get lower word aligned address */
 	dst = (addr & ~3);

 	/* handle unaligned start bytes */
 	l = addr - dst;
 	if (l != 0) {
 		tmp_le = 0;
 		for (i = 0, cp = (uchar *)dst; i < l; ++i, ++cp)
 			tmp_le |= *cp << (i * 8);

 		for (; (i < 4) && (cnt > 0); ++i, ++src, --cnt, ++cp)
 			tmp_le |= *src << (i * 8);

 		for (; (cnt == 0) && (i < 4); ++i, ++cp)
 			tmp_le |= *cp << (i * 8);

 		rc = write_word(info, dst, tmp_le);
 		if (rc)
 			goto out;

 		dst += 4;
 	}

 	/* handle word aligned part */
 	while (cnt >= 4) {
 		tmp_le = src[0] | src[1] << 8 | src[2] << 16 | src[3] << 24;
 		rc = write_word(info, dst, tmp_le);
 		if (rc)
 			goto out;
 		src += 4;
 		dst += 4;
 		cnt -= 4;
 	}

 	if (cnt == 0) {
 		rc = ERR_OK;
 		goto out;
 	}

 	/* handle unaligned tail bytes */
 	tmp_le = 0;
 	for (i = 0, cp = (uchar *)dst; (i < 4) && (cnt > 0); ++i, ++cp) {
 		tmp_le |= *src++ << (i * 8);
 		--cnt;
 	}

 	for (; i < 4; ++i, ++cp)
 		tmp_le |= *cp << (i * 8);

 	rc = write_word(info, dst, tmp_le);
 out:
 	/*
 	 * flash content updated by nvm controller but CPU cache might
 	 * have stale data, so invalidate dcache.
 	 */
 	invalidate_dcache_range(addr, addr + len);

 	printf(" done\n");
 	return rc;
 }

 void flash_print_info(flash_info_t *info)
 {
 	int i;

 	if (info->flash_id == FLASH_UNKNOWN) {
 		printf("missing or unknown FLASH type\n");
 		return;
 	}

 	switch (info->flash_id & FLASH_VENDMASK) {
 	case FLASH_MAN_MCHP:
 		printf("Microchip Technology ");
 		break;
 	default:
 		printf("Unknown Vendor ");
 		break;
 	}

 	switch (info->flash_id & FLASH_TYPEMASK) {
 	case FLASH_MCHP100T:
 		printf("Internal (8 Mbit, 64 x 16k)\n");
 		break;
 	default:
 		printf("Unknown Chip Type\n");
 		break;
 	}

 	printf("  Size: %ld MB in %d Sectors\n",
 	       info->size >> 20, info->sector_count);

 	printf("  Sector Start Addresses:");
 	for (i = 0; i < info->sector_count; ++i) {
 		if ((i % 5) == 0)
 			printf("\n   ");

 		printf(" %08lX%s", info->start[i],
 		       info->protect[i] ? " (RO)" : "     ");
 	}
 	printf("\n");
 }

 unsigned long flash_init(void)
 {
 	unsigned long size = 0;
 	struct udevice *dev;
 	int bank;

 	/* probe every MTD device */
 	for (uclass_first_device(UCLASS_MTD, &dev); dev;
 	     uclass_next_device(&dev)) {
 		/* nop */
 	}

 	/* calc total flash size */
 	for (bank = 0; bank < CONFIG_SYS_MAX_FLASH_BANKS; ++bank)
 		size += flash_info[bank].size;

 	return size;
 }

 static void pic32_flash_bank_init(flash_info_t *info,
 				  ulong base, ulong size)
 {
 	ulong sect_size;
 	int sect;

 	/* device & manufacturer code */
 	info->flash_id = FLASH_MAN_MCHP | FLASH_MCHP100T;
 	info->sector_count = CONFIG_SYS_MAX_FLASH_SECT;
 	info->size = size;

 	/* update sector (i.e page) info */
 	sect_size = info->size / info->sector_count;
 	for (sect = 0; sect < info->sector_count; sect++) {
 		info->start[sect] = base;
 		/* protect each sector by default */
 		info->protect[sect] = 1;
 		base += sect_size;
 	}
 }

 static int pic32_flash_probe(struct udevice *dev)
 {
 	void *blob = (void *)gd->fdt_blob;
 	int node = dev_of_offset(dev);
 	const char *list, *end;
 	const fdt32_t *cell;
 	unsigned long addr, size;
 	int parent, addrc, sizec;
 	flash_info_t *info;
 	int len, idx;

 	/*
 	 * decode regs. there are multiple reg tuples, and they need to
 	 * match with reg-names.
 	 */
 	parent = fdt_parent_offset(blob, node);
 	fdt_support_default_count_cells(blob, parent, &addrc, &sizec);
 	list = fdt_getprop(blob, node, "reg-names", &len);
 	if (!list)
 		return -ENOENT;

 	end = list + len;
 	cell = fdt_getprop(blob, node, "reg", &len);
 	if (!cell)
 		return -ENOENT;

 	for (idx = 0, info = &flash_info[0]; list < end;) {
 		addr = fdt_translate_address((void *)blob, node, cell + idx);
 		size = fdt_addr_to_cpu(cell[idx + addrc]);
 		len = strlen(list);
 		if (!strncmp(list, "nvm", len)) {
 			/* NVM controller */
 			nvm_regs_p = ioremap(addr, size);
 		} else if (!strncmp(list, "bank", 4)) {
 			/* Flash bank: use kseg0 cached address */
 			pic32_flash_bank_init(info, CKSEG0ADDR(addr), size);
 			info++;
 		}
 		idx += addrc + sizec;
 		list += len + 1;
 	}

 	/* disable flash write/erase operations */
 	writel(NVM_WREN, &nvm_regs_p->ctrl.clr);

 #if (CONFIG_SYS_MONITOR_BASE >= CONFIG_SYS_FLASH_BASE)
 	/* monitor protection ON by default */
 	flash_protect(FLAG_PROTECT_SET,
 		      CONFIG_SYS_MONITOR_BASE,
 		      CONFIG_SYS_MONITOR_BASE + monitor_flash_len - 1,
 		      &flash_info[0]);
 #endif

 #ifdef CONFIG_ENV_IS_IN_FLASH
 	/* ENV protection ON by default */
 	flash_protect(FLAG_PROTECT_SET,
 		      CONFIG_ENV_ADDR,
 		      CONFIG_ENV_ADDR + CONFIG_ENV_SECT_SIZE - 1,
 		      &flash_info[0]);
 #endif
 	return 0;
 }

 static const struct udevice_id pic32_flash_ids[] = {
 	{ .compatible = "microchip,pic32mzda-flash" },
 	{}
 };

 U_BOOT_DRIVER(pic32_flash) = {
 	.name	= "pic32_flash",
 	.id	= UCLASS_MTD,
 	.of_match = pic32_flash_ids,
 	.probe	= pic32_flash_probe,
 };
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Copyright (C) 2015
	* Cristian Birsan <cristian.birsan@microchip.com>
	* Purna Chandra Mandal <purna.mandal@microchip.com>
	*/

	#include <common.h>
	#include <cpu_func.h>
	#include <dm.h>
	#include <fdt_support.h>
	#include <flash.h>
	#include <init.h>
	#include <irq_func.h>
	#include <asm/global_data.h>
	#include <linux/bitops.h>
	#include <mach/pic32.h>
	#include <wait_bit.h>

	DECLARE_GLOBAL_DATA_PTR;

	/* NVM Controller registers */
	struct pic32_reg_nvm {
	struct pic32_reg_atomic ctrl;
	struct pic32_reg_atomic key;
	struct pic32_reg_atomic addr;
	struct pic32_reg_atomic data;
	};

	/* NVM operations */
	#define NVMOP_NOP 0
	#define NVMOP_WORD_WRITE 1
	#define NVMOP_PAGE_ERASE 4

	/* NVM control bits */
	#define NVM_WR BIT(15)
	#define NVM_WREN BIT(14)
	#define NVM_WRERR BIT(13)
	#define NVM_LVDERR BIT(12)

	/* NVM programming unlock register */
	#define LOCK_KEY 0x0
	#define UNLOCK_KEY1 0xaa996655
	#define UNLOCK_KEY2 0x556699aa

	/*
	* PIC32 flash banks consist of number of pages, each page
	* into number of rows and rows into number of words.
	* Here we will maintain page information instead of sector.
	*/
	flash_info_t flash_info[CONFIG_SYS_MAX_FLASH_BANKS];
	static struct pic32_reg_nvm *nvm_regs_p;

	static inline void flash_initiate_operation(u32 nvmop)
	{
	/* set operation */
	writel(nvmop, &nvm_regs_p->ctrl.raw);

	/* enable flash write */
	writel(NVM_WREN, &nvm_regs_p->ctrl.set);

	/* unlock sequence */
	writel(LOCK_KEY, &nvm_regs_p->key.raw);
	writel(UNLOCK_KEY1, &nvm_regs_p->key.raw);
	writel(UNLOCK_KEY2, &nvm_regs_p->key.raw);

	/* initiate operation */
	writel(NVM_WR, &nvm_regs_p->ctrl.set);
	}

	static int flash_wait_till_busy(const char *func, ulong timeout)
	{
	int ret = wait_for_bit_le32(&nvm_regs_p->ctrl.raw,
	NVM_WR, false, timeout, false);

	return ret ? ERR_TIMEOUT : ERR_OK;
	}

	static inline int flash_complete_operation(void)
	{
	u32 tmp;

	tmp = readl(&nvm_regs_p->ctrl.raw);
	if (tmp & NVM_WRERR) {
	printf("Error in Block Erase - Lock Bit may be set!\n");
	flash_initiate_operation(NVMOP_NOP);
	return ERR_PROTECTED;
	}

	if (tmp & NVM_LVDERR) {
	printf("Error in Block Erase - low-vol detected!\n");
	flash_initiate_operation(NVMOP_NOP);
	return ERR_NOT_ERASED;
	}

	/* disable flash write or erase operation */
	writel(NVM_WREN, &nvm_regs_p->ctrl.clr);

	return ERR_OK;
	}

	/*
	* Erase flash sectors, returns:
	* ERR_OK - OK
	* ERR_INVAL - invalid sector arguments
	* ERR_TIMEOUT - write timeout
	* ERR_NOT_ERASED - Flash not erased
	* ERR_UNKNOWN_FLASH_VENDOR - incorrect flash
	*/
	int flash_erase(flash_info_t *info, int s_first, int s_last)
	{
	ulong sect_start, sect_end, flags;
	int prot, sect;
	int rc;

	if ((info->flash_id & FLASH_VENDMASK) != FLASH_MAN_MCHP) {
	printf("Can't erase unknown flash type %08lx - aborted\n",
	info->flash_id);
	return ERR_UNKNOWN_FLASH_VENDOR;
	}

	if ((s_first < 0) \|\| (s_first > s_last)) {
	printf("- no sectors to erase\n");
	return ERR_INVAL;
	}

	prot = 0;
	for (sect = s_first; sect <= s_last; ++sect) {
	if (info->protect[sect])
	prot++;
	}

	if (prot)
	printf("- Warning: %d protected sectors will not be erased!\n",
	prot);
	else
	printf("\n");

	/* erase on unprotected sectors */
	for (sect = s_first; sect <= s_last; sect++) {
	if (info->protect[sect])
	continue;

	/* disable interrupts */
	flags = disable_interrupts();

	/* write destination page address (physical) */
	sect_start = CPHYSADDR(info->start[sect]);
	writel(sect_start, &nvm_regs_p->addr.raw);

	/* page erase */
	flash_initiate_operation(NVMOP_PAGE_ERASE);

	/* wait */
	rc = flash_wait_till_busy(__func__,
	CONFIG_SYS_FLASH_ERASE_TOUT);

	/* re-enable interrupts if necessary */
	if (flags)
	enable_interrupts();

	if (rc != ERR_OK)
	return rc;

	rc = flash_complete_operation();
	if (rc != ERR_OK)
	return rc;

	/*
	* flash content is updated but cache might contain stale
	* data, so invalidate dcache.
	*/
	sect_end = info->start[sect] + info->size / info->sector_count;
	invalidate_dcache_range(info->start[sect], sect_end);
	}

	printf(" done\n");
	return ERR_OK;
	}

	int page_erase(flash_info_t *info, int sect)
	{
	return 0;
	}

	/* Write a word to flash */
	static int write_word(flash_info_t *info, ulong dest, ulong word)
	{
	ulong flags;
	int rc;

	/* read flash to check if it is sufficiently erased */
	if ((readl((void __iomem *)dest) & word) != word) {
	printf("Error, Flash not erased!\n");
	return ERR_NOT_ERASED;
	}

	/* disable interrupts */
	flags = disable_interrupts();

	/* update destination page address (physical) */
	writel(CPHYSADDR(dest), &nvm_regs_p->addr.raw);
	writel(word, &nvm_regs_p->data.raw);

	/* word write */
	flash_initiate_operation(NVMOP_WORD_WRITE);

	/* wait for operation to complete */
	rc = flash_wait_till_busy(__func__, CONFIG_SYS_FLASH_WRITE_TOUT);

	/* re-enable interrupts if necessary */
	if (flags)
	enable_interrupts();

	if (rc != ERR_OK)
	return rc;

	return flash_complete_operation();
	}

	/*
	* Copy memory to flash, returns:
	* ERR_OK - OK
	* ERR_TIMEOUT - write timeout
	* ERR_NOT_ERASED - Flash not erased
	*/
	int write_buff(flash_info_t info, uchar src, ulong addr, ulong cnt)
	{
	ulong dst, tmp_le, len = cnt;
	int i, l, rc;
	uchar *cp;

	/* get lower word aligned address */
	dst = (addr & ~3);

	/* handle unaligned start bytes */
	l = addr - dst;
	if (l != 0) {
	tmp_le = 0;
	for (i = 0, cp = (uchar *)dst; i < l; ++i, ++cp)
	tmp_le \|= cp << (i 8);

	for (; (i < 4) && (cnt > 0); ++i, ++src, --cnt, ++cp)
	tmp_le \|= src << (i 8);

	for (; (cnt == 0) && (i < 4); ++i, ++cp)
	tmp_le \|= cp << (i 8);

	rc = write_word(info, dst, tmp_le);
	if (rc)
	goto out;

	dst += 4;
	}

	/* handle word aligned part */
	while (cnt >= 4) {
	tmp_le = src[0] \| src[1] << 8 \| src[2] << 16 \| src[3] << 24;
	rc = write_word(info, dst, tmp_le);
	if (rc)
	goto out;
	src += 4;
	dst += 4;
	cnt -= 4;
	}

	if (cnt == 0) {
	rc = ERR_OK;
	goto out;
	}

	/* handle unaligned tail bytes */
	tmp_le = 0;
	for (i = 0, cp = (uchar *)dst; (i < 4) && (cnt > 0); ++i, ++cp) {
	tmp_le \|= src++ << (i 8);
	--cnt;
	}

	for (; i < 4; ++i, ++cp)
	tmp_le \|= cp << (i 8);

	rc = write_word(info, dst, tmp_le);
	out:
	/*
	* flash content updated by nvm controller but CPU cache might
	* have stale data, so invalidate dcache.
	*/
	invalidate_dcache_range(addr, addr + len);

	printf(" done\n");
	return rc;
	}

	void flash_print_info(flash_info_t *info)
	{
	int i;

	if (info->flash_id == FLASH_UNKNOWN) {
	printf("missing or unknown FLASH type\n");
	return;
	}

	switch (info->flash_id & FLASH_VENDMASK) {
	case FLASH_MAN_MCHP:
	printf("Microchip Technology ");
	break;
	default:
	printf("Unknown Vendor ");
	break;
	}

	switch (info->flash_id & FLASH_TYPEMASK) {
	case FLASH_MCHP100T:
	printf("Internal (8 Mbit, 64 x 16k)\n");
	break;
	default:
	printf("Unknown Chip Type\n");
	break;
	}

	printf(" Size: %ld MB in %d Sectors\n",
	info->size >> 20, info->sector_count);

	printf(" Sector Start Addresses:");
	for (i = 0; i < info->sector_count; ++i) {
	if ((i % 5) == 0)
	printf("\n ");

	printf(" %08lX%s", info->start[i],
	info->protect[i] ? " (RO)" : " ");
	}
	printf("\n");
	}

	unsigned long flash_init(void)
	{
	unsigned long size = 0;
	struct udevice *dev;
	int bank;

	/* probe every MTD device */
	for (uclass_first_device(UCLASS_MTD, &dev); dev;
	uclass_next_device(&dev)) {
	/* nop */
	}

	/* calc total flash size */
	for (bank = 0; bank < CONFIG_SYS_MAX_FLASH_BANKS; ++bank)
	size += flash_info[bank].size;

	return size;
	}

	static void pic32_flash_bank_init(flash_info_t *info,
	ulong base, ulong size)
	{
	ulong sect_size;
	int sect;

	/* device & manufacturer code */
	info->flash_id = FLASH_MAN_MCHP \| FLASH_MCHP100T;
	info->sector_count = CONFIG_SYS_MAX_FLASH_SECT;
	info->size = size;

	/* update sector (i.e page) info */
	sect_size = info->size / info->sector_count;
	for (sect = 0; sect < info->sector_count; sect++) {
	info->start[sect] = base;
	/* protect each sector by default */
	info->protect[sect] = 1;
	base += sect_size;
	}
	}

	static int pic32_flash_probe(struct udevice *dev)
	{
	void blob = (void )gd->fdt_blob;
	int node = dev_of_offset(dev);
	const char list, end;
	const fdt32_t *cell;
	unsigned long addr, size;
	int parent, addrc, sizec;
	flash_info_t *info;
	int len, idx;

	/*
	* decode regs. there are multiple reg tuples, and they need to
	* match with reg-names.
	*/
	parent = fdt_parent_offset(blob, node);
	fdt_support_default_count_cells(blob, parent, &addrc, &sizec);
	list = fdt_getprop(blob, node, "reg-names", &len);
	if (!list)
	return -ENOENT;

	end = list + len;
	cell = fdt_getprop(blob, node, "reg", &len);
	if (!cell)
	return -ENOENT;

	for (idx = 0, info = &flash_info[0]; list < end;) {
	addr = fdt_translate_address((void *)blob, node, cell + idx);
	size = fdt_addr_to_cpu(cell[idx + addrc]);
	len = strlen(list);
	if (!strncmp(list, "nvm", len)) {
	/* NVM controller */
	nvm_regs_p = ioremap(addr, size);
	} else if (!strncmp(list, "bank", 4)) {
	/* Flash bank: use kseg0 cached address */
	pic32_flash_bank_init(info, CKSEG0ADDR(addr), size);
	info++;
	}
	idx += addrc + sizec;
	list += len + 1;
	}

	/* disable flash write/erase operations */
	writel(NVM_WREN, &nvm_regs_p->ctrl.clr);

	#if (CONFIG_SYS_MONITOR_BASE >= CONFIG_SYS_FLASH_BASE)
	/* monitor protection ON by default */
	flash_protect(FLAG_PROTECT_SET,
	CONFIG_SYS_MONITOR_BASE,
	CONFIG_SYS_MONITOR_BASE + monitor_flash_len - 1,
	&flash_info[0]);
	#endif

	#ifdef CONFIG_ENV_IS_IN_FLASH
	/* ENV protection ON by default */
	flash_protect(FLAG_PROTECT_SET,
	CONFIG_ENV_ADDR,
	CONFIG_ENV_ADDR + CONFIG_ENV_SECT_SIZE - 1,
	&flash_info[0]);
	#endif
	return 0;
	}

	static const struct udevice_id pic32_flash_ids[] = {
	{ .compatible = "microchip,pic32mzda-flash" },
	{}
	};

	U_BOOT_DRIVER(pic32_flash) = {
	.name = "pic32_flash",
	.id = UCLASS_MTD,
	.of_match = pic32_flash_ids,
	.probe = pic32_flash_probe,
	};