drivers: mtd: add Microchip PIC32 internal non-CFI flash driver.

PIC32 internal flash devices are parallel NOR flash divided into
number of banks to allow erase-programming in one while fetch and
execution continues on other. As the flash banks are memory mapped
stored code can be executed directly from flash (XIP), also there
is additional hardware logic to prefetch and cache contents to
improve execution performance. These flash can also be used to
store user data (like environment).
Flash erase and programming are handled by on-chip NVM controller.

Driver implemented driver model but MTD is not really support.

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/mtd/Kconfig

@@ -28,6 +28,13 @@ config ALTERA_QSPI
 	  NOR flash to parallel flash interface. Please find details on the
 	  "Embedded Peripherals IP User Guide" of Altera.
 
+config FLASH_PIC32
+	bool "Microchip PIC32 Flash driver"
+	depends on MACH_PIC32 && MTD
+	help
+	  This enables access to Microchip PIC32 internal non-CFI flash
+	  chips through PIC32 Non-Volatile-Memory Controller.
+
 endmenu
 
 source "drivers/mtd/nand/Kconfig"

drivers/mtd/Makefile

@@ -19,5 +19,6 @@ obj-$(CONFIG_HAS_DATAFLASH) += dataflash.o
 obj-$(CONFIG_FTSMC020) += ftsmc020.o
 obj-$(CONFIG_FLASH_CFI_LEGACY) += jedec_flash.o
 obj-$(CONFIG_MW_EEPROM) += mw_eeprom.o
+obj-$(CONFIG_FLASH_PIC32) += pic32_flash.o
 obj-$(CONFIG_ST_SMI) += st_smi.o
 obj-$(CONFIG_STM32_FLASH) += stm32_flash.o

drivers/mtd/pic32_flash.c

@@ -0,0 +1,444 @@
+/*
+ * Copyright (C) 2015
+ * Cristian Birsan <cristian.birsan@microchip.com>
+ * Purna Chandra Mandal <purna.mandal@microchip.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <fdt_support.h>
+#include <flash.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(__func__, &nvm_regs_p->ctrl.raw,
+			       NVM_WR, false, timeout, false);
+
+	return ret ? ERR_TIMOUT : 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_TIMOUT - 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_TIMOUT - 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;
+	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);
+	of_bus_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,
+};