--- /dev/null
+/*
+ * SPL driver for Diskonchip G4 nand flash
+ *
+ * Copyright (C) 2013 Mike Dunn <mikedunn@newsguy.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * This driver basically mimics the load functionality of a typical IPL (initial
+ * program loader) resident in the 2k NOR-like region of the docg4 that is
+ * mapped to the reset vector. It allows the u-boot SPL to continue loading if
+ * the IPL loads a fixed number of flash blocks that is insufficient to contain
+ * the entire u-boot image. In this case, a concatenated spl + u-boot image is
+ * written at the flash offset from which the IPL loads an image, and when the
+ * IPL jumps to the SPL, the SPL resumes loading where the IPL left off. See
+ * the palmtreo680 for an example.
+ *
+ * This driver assumes that the data was written to the flash using the device's
+ * "reliable" mode, and also assumes that each 512 byte page is stored
+ * redundantly in the subsequent page. This storage format is likely to be used
+ * by all boards that boot from the docg4. The format compensates for the lack
+ * of ecc in the IPL.
+ *
+ * Reliable mode reduces the capacity of a block by half, and the redundant
+ * pages reduce it by half again. As a result, the normal 256k capacity of a
+ * block is reduced to 64k for the purposes of the IPL/SPL.
+ */
+
+#include <asm/io.h>
+#include <linux/mtd/docg4.h>
+
+/* forward declarations */
+static inline void write_nop(void __iomem *docptr);
+static int poll_status(void __iomem *docptr);
+static void write_addr(void __iomem *docptr, uint32_t docg4_addr);
+static void address_sequence(unsigned int g4_page, unsigned int g4_index,
+ void __iomem *docptr);
+static int docg4_load_block_reliable(uint32_t flash_offset, void *dest_addr);
+
+int nand_spl_load_image(uint32_t offs, unsigned int size, void *dst)
+{
+ void *load_addr = dst;
+ uint32_t flash_offset = offs;
+ const unsigned int block_count =
+ (size + DOCG4_BLOCK_CAPACITY_SPL - 1)
+ / DOCG4_BLOCK_CAPACITY_SPL;
+ int i;
+
+ for (i = 0; i < block_count; i++) {
+ int ret = docg4_load_block_reliable(flash_offset, load_addr);
+ if (ret)
+ return ret;
+ load_addr += DOCG4_BLOCK_CAPACITY_SPL;
+ flash_offset += DOCG4_BLOCK_SIZE;
+ }
+ return 0;
+}
+
+static inline void write_nop(void __iomem *docptr)
+{
+ writew(0, docptr + DOC_NOP);
+}
+
+static int poll_status(void __iomem *docptr)
+{
+ /*
+ * Busy-wait for the FLASHREADY bit to be set in the FLASHCONTROL
+ * register. Operations known to take a long time (e.g., block erase)
+ * should sleep for a while before calling this.
+ */
+
+ uint8_t flash_status;
+
+ /* hardware quirk requires reading twice initially */
+ flash_status = readb(docptr + DOC_FLASHCONTROL);
+
+ do {
+ flash_status = readb(docptr + DOC_FLASHCONTROL);
+ } while (!(flash_status & DOC_CTRL_FLASHREADY));
+
+ return 0;
+}
+
+static void write_addr(void __iomem *docptr, uint32_t docg4_addr)
+{
+ /* write the four address bytes packed in docg4_addr to the device */
+
+ writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
+ docg4_addr >>= 8;
+ writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
+ docg4_addr >>= 8;
+ writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
+ docg4_addr >>= 8;
+ writeb(docg4_addr & 0xff, docptr + DOC_FLASHADDRESS);
+}
+
+static void address_sequence(unsigned int g4_page, unsigned int g4_index,
+ void __iomem *docptr)
+{
+ writew(DOCG4_SEQ_PAGE_READ, docptr + DOC_FLASHSEQUENCE);
+ writew(DOCG4_CMD_PAGE_READ, docptr + DOC_FLASHCOMMAND);
+ write_nop(docptr);
+ write_addr(docptr, ((uint32_t)g4_page << 16) | g4_index);
+ write_nop(docptr);
+}
+
+static int docg4_load_block_reliable(uint32_t flash_offset, void *dest_addr)
+{
+ void __iomem *docptr = (void *)CONFIG_SYS_NAND_BASE;
+ unsigned int g4_page = flash_offset >> 11; /* 2k page */
+ const unsigned int last_g4_page = g4_page + 0x80; /* last in block */
+ int g4_index = 0;
+ uint16_t flash_status;
+ uint16_t *buf;
+
+ /* flash_offset must be aligned to the start of a block */
+ if (flash_offset & 0x3ffff)
+ return -1;
+
+ writew(DOC_SEQ_RESET, docptr + DOC_FLASHSEQUENCE);
+ writew(DOC_CMD_RESET, docptr + DOC_FLASHCOMMAND);
+ write_nop(docptr);
+ write_nop(docptr);
+ poll_status(docptr);
+ write_nop(docptr);
+ writew(0x45, docptr + DOC_FLASHSEQUENCE);
+ writew(0xa3, docptr + DOC_FLASHCOMMAND);
+ write_nop(docptr);
+ writew(0x22, docptr + DOC_FLASHCOMMAND);
+ write_nop(docptr);
+
+ /* read 1st 4 oob bytes of first subpage of block */
+ address_sequence(g4_page, 0x0100, docptr); /* index at oob */
+ write_nop(docptr);
+ flash_status = readw(docptr + DOC_FLASHCONTROL);
+ flash_status = readw(docptr + DOC_FLASHCONTROL);
+ if (flash_status & 0x06) /* sequence or protection errors */
+ return -1;
+ writew(DOCG4_CMD_READ2, docptr + DOC_FLASHCOMMAND);
+ write_nop(docptr);
+ write_nop(docptr);
+ poll_status(docptr);
+ writew(DOC_ECCCONF0_READ_MODE | 4, docptr + DOC_ECCCONF0);
+ write_nop(docptr);
+ write_nop(docptr);
+ write_nop(docptr);
+ write_nop(docptr);
+ write_nop(docptr);
+
+ /*
+ * Here we read the first four oob bytes of the first page of the block.
+ * The IPL on the palmtreo680 requires that this contain a 32 bit magic
+ * number, or the load aborts. We'll ignore it.
+ */
+ readw(docptr + 0x103c); /* hw quirk; 1st read discarded */
+ readw(docptr + 0x103c); /* lower 16 bits of magic number */
+ readw(docptr + DOCG4_MYSTERY_REG); /* upper 16 bits of magic number */
+ writew(0, docptr + DOC_DATAEND);
+ write_nop(docptr);
+ write_nop(docptr);
+
+ /* load contents of block to memory */
+ buf = (uint16_t *)dest_addr;
+ do {
+ int i;
+
+ address_sequence(g4_page, g4_index, docptr);
+ writew(DOCG4_CMD_READ2,
+ docptr + DOC_FLASHCOMMAND);
+ write_nop(docptr);
+ write_nop(docptr);
+ poll_status(docptr);
+ writew(DOC_ECCCONF0_READ_MODE |
+ DOC_ECCCONF0_ECC_ENABLE |
+ DOCG4_BCH_SIZE,
+ docptr + DOC_ECCCONF0);
+ write_nop(docptr);
+ write_nop(docptr);
+ write_nop(docptr);
+ write_nop(docptr);
+ write_nop(docptr);
+
+ /* read the 512 bytes of page data, 2 bytes at a time */
+ readw(docptr + 0x103c); /* hw quirk */
+ for (i = 0; i < 256; i++)
+ *buf++ = readw(docptr + 0x103c);
+
+ /* read oob, but discard it */
+ for (i = 0; i < 7; i++)
+ readw(docptr + 0x103c);
+ readw(docptr + DOCG4_OOB_6_7);
+ readw(docptr + DOCG4_OOB_6_7);
+
+ writew(0, docptr + DOC_DATAEND);
+ write_nop(docptr);
+ write_nop(docptr);
+
+ if (!(g4_index & 0x100)) {
+ /* not redundant subpage read; check for ecc error */
+ write_nop(docptr);
+ flash_status = readw(docptr + DOC_ECCCONF1);
+ flash_status = readw(docptr + DOC_ECCCONF1);
+ if (flash_status & 0x80) { /* ecc error */
+ g4_index += 0x108; /* read redundant subpage */
+ buf -= 256; /* back up ram ptr */
+ continue;
+ } else /* no ecc error */
+ g4_index += 0x210; /* skip redundant subpage */
+ } else /* redundant page was just read; skip ecc error check */
+ g4_index += 0x108;
+
+ if (g4_index == 0x420) { /* finished with 2k page */
+ g4_index = 0;
+ g4_page += 2; /* odd-numbered 2k pages skipped */
+ }
+
+ } while (g4_page != last_g4_page); /* while still on same block */
+
+ return 0;
+}
projects / karo-tx-uboot.git / blobdiff