[MTD] LPDDR qinfo probing.

LPDDR flash chips are based on completely new kind of chips probing.
Device capabilities are available via special request.
We sent field request command which contains Major and Minor numbers - and
recieve corresponend value.
All requests are performed within PFOW window.
Detailed information about qinfo records can be found here:
http://www.numonyx.com/Documents/Datasheets/DS-315768_Velocity-Discrete.pdfSigned-off-by: NAlexey Korolev <akorolev@infradead.org>
Acked-by: NJared Hulbert <jaredeh@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/lpddr/qinfo_probe.c

+/*
+ * Probing flash chips with QINFO records.
+ * (C) 2008 Korolev Alexey <akorolev@infradead.org>
+ * (C) 2008 Vasiliy Leonenko <vasiliy.leonenko@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+
+#include <linux/mtd/xip.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/pfow.h>
+#include <linux/mtd/qinfo.h>
+
+static int lpddr_chip_setup(struct map_info *map, struct lpddr_private *lpddr);
+struct mtd_info *lpddr_probe(struct map_info *map);
+static struct lpddr_private *lpddr_probe_chip(struct map_info *map);
+static int lpddr_pfow_present(struct map_info *map,
+			struct lpddr_private *lpddr);
+
+static struct qinfo_query_info qinfo_array[] = {
+	/* General device info */
+	{0, 0, "DevSizeShift", "Device size 2^n bytes"},
+	{0, 3, "BufSizeShift", "Program buffer size 2^n bytes"},
+	/* Erase block information */
+	{1, 1, "TotalBlocksNum", "Total number of blocks"},
+	{1, 2, "UniformBlockSizeShift", "Uniform block size 2^n bytes"},
+	/* Partition information */
+	{2, 1, "HWPartsNum", "Number of hardware partitions"},
+	/* Optional features */
+	{5, 1, "SuspEraseSupp", "Suspend erase supported"},
+	/* Operation typical time */
+	{10, 0, "SingleWordProgTime", "Single word program 2^n u-sec"},
+	{10, 1, "ProgBufferTime", "Program buffer write 2^n u-sec"},
+	{10, 2, "BlockEraseTime", "Block erase 2^n m-sec"},
+	{10, 3, "FullChipEraseTime", "Full chip erase 2^n m-sec"},
+};
+
+static long lpddr_get_qinforec_pos(struct map_info *map, char *id_str)
+{
+	int qinfo_lines = sizeof(qinfo_array)/sizeof(struct qinfo_query_info);
+	int i;
+	int bankwidth = map_bankwidth(map) * 8;
+	int major, minor;
+
+	for (i = 0; i < qinfo_lines; i++) {
+		if (strcmp(id_str, qinfo_array[i].id_str) == 0) {
+			major = qinfo_array[i].major & ((1 << bankwidth) - 1);
+			minor = qinfo_array[i].minor & ((1 << bankwidth) - 1);
+			return minor | (major << bankwidth);
+		}
+	}
+	printk(KERN_ERR"%s qinfo id string is wrong! \n", map->name);
+	BUG();
+	return -1;
+}
+
+static uint16_t lpddr_info_query(struct map_info *map, char *id_str)
+{
+	unsigned int dsr, val;
+	int bits_per_chip = map_bankwidth(map) * 8;
+	unsigned long adr = lpddr_get_qinforec_pos(map, id_str);
+	int attempts = 20;
+
+	/* Write a request for the PFOW record */
+	map_write(map, CMD(LPDDR_INFO_QUERY),
+			map->pfow_base + PFOW_COMMAND_CODE);
+	map_write(map, CMD(adr & ((1 << bits_per_chip) - 1)),
+			map->pfow_base + PFOW_COMMAND_ADDRESS_L);
+	map_write(map, CMD(adr >> bits_per_chip),
+			map->pfow_base + PFOW_COMMAND_ADDRESS_H);
+	map_write(map, CMD(LPDDR_START_EXECUTION),
+			map->pfow_base + PFOW_COMMAND_EXECUTE);
+
+	while ((attempts--) > 0) {
+		dsr = CMDVAL(map_read(map, map->pfow_base + PFOW_DSR));
+		if (dsr & DSR_READY_STATUS)
+			break;
+		udelay(10);
+	}
+
+	val = CMDVAL(map_read(map, map->pfow_base + PFOW_COMMAND_DATA));
+	return val;
+}
+
+static int lpddr_pfow_present(struct map_info *map, struct lpddr_private *lpddr)
+{
+	map_word pfow_val[4];
+
+	/* Check identification string */
+	pfow_val[0] = map_read(map, map->pfow_base + PFOW_QUERY_STRING_P);
+	pfow_val[1] = map_read(map, map->pfow_base + PFOW_QUERY_STRING_F);
+	pfow_val[2] = map_read(map, map->pfow_base + PFOW_QUERY_STRING_O);
+	pfow_val[3] = map_read(map, map->pfow_base + PFOW_QUERY_STRING_W);
+
+	if (!map_word_equal(map, CMD('P'), pfow_val[0]))
+		goto out;
+
+	if (!map_word_equal(map, CMD('F'), pfow_val[1]))
+		goto out;
+
+	if (!map_word_equal(map, CMD('O'), pfow_val[2]))
+		goto out;
+
+	if (!map_word_equal(map, CMD('W'), pfow_val[3]))
+		goto out;
+
+	return 1;	/* "PFOW" is found */
+out:
+	printk(KERN_WARNING"%s: PFOW string at 0x%lx is not found \n",
+					map->name, map->pfow_base);
+	return 0;
+}
+
+static int lpddr_chip_setup(struct map_info *map, struct lpddr_private *lpddr)
+{
+
+	lpddr->qinfo = kmalloc(sizeof(struct qinfo_chip), GFP_KERNEL);
+	if (!lpddr->qinfo) {
+		printk(KERN_WARNING "%s: no memory for LPDDR qinfo structure\n",
+				map->name);
+		return 0;
+	}
+	memset(lpddr->qinfo, 0, sizeof(struct qinfo_chip));
+
+	/* Get the ManuID */
+	lpddr->ManufactId = CMDVAL(map_read(map, map->pfow_base + PFOW_MANUFACTURER_ID));
+	/* Get the DeviceID */
+	lpddr->DevId = CMDVAL(map_read(map, map->pfow_base + PFOW_DEVICE_ID));
+	/* read parameters from chip qinfo table */
+	lpddr->qinfo->DevSizeShift = lpddr_info_query(map, "DevSizeShift");
+	lpddr->qinfo->TotalBlocksNum = lpddr_info_query(map, "TotalBlocksNum");
+	lpddr->qinfo->BufSizeShift = lpddr_info_query(map, "BufSizeShift");
+	lpddr->qinfo->HWPartsNum = lpddr_info_query(map, "HWPartsNum");
+	lpddr->qinfo->UniformBlockSizeShift =
+				lpddr_info_query(map, "UniformBlockSizeShift");
+	lpddr->qinfo->SuspEraseSupp = lpddr_info_query(map, "SuspEraseSupp");
+	lpddr->qinfo->SingleWordProgTime =
+				lpddr_info_query(map, "SingleWordProgTime");
+	lpddr->qinfo->ProgBufferTime = lpddr_info_query(map, "ProgBufferTime");
+	lpddr->qinfo->BlockEraseTime = lpddr_info_query(map, "BlockEraseTime");
+	return 1;
+}
+static struct lpddr_private *lpddr_probe_chip(struct map_info *map)
+{
+	struct lpddr_private lpddr;
+	struct lpddr_private *retlpddr;
+	int numvirtchips;
+
+
+	if ((map->pfow_base + 0x1000) >= map->size) {
+		printk(KERN_NOTICE"%s Probe at base (0x%08lx) past the end of"
+				"the map(0x%08lx)\n", map->name,
+				(unsigned long)map->pfow_base, map->size - 1);
+		return NULL;
+	}
+	memset(&lpddr, 0, sizeof(struct lpddr_private));
+	if (!lpddr_pfow_present(map, &lpddr))
+		return NULL;
+
+	if (!lpddr_chip_setup(map, &lpddr))
+		return NULL;
+
+	/* Ok so we found a chip */
+	lpddr.chipshift = lpddr.qinfo->DevSizeShift;
+	lpddr.numchips = 1;
+
+	numvirtchips = lpddr.numchips * lpddr.qinfo->HWPartsNum;
+	retlpddr = kmalloc(sizeof(struct lpddr_private) +
+			numvirtchips * sizeof(struct flchip), GFP_KERNEL);
+	if (!retlpddr)
+		return NULL;
+
+	memset(retlpddr, 0, sizeof(struct lpddr_private) +
+				numvirtchips * sizeof(struct flchip));
+	memcpy(retlpddr, &lpddr, sizeof(struct lpddr_private));
+
+	retlpddr->numchips = numvirtchips;
+	retlpddr->chipshift = retlpddr->qinfo->DevSizeShift -
+				__ffs(retlpddr->qinfo->HWPartsNum);
+
+	return retlpddr;
+}
+
+struct mtd_info *lpddr_probe(struct map_info *map)
+{
+	struct mtd_info *mtd = NULL;
+	struct lpddr_private *lpddr;
+
+	/* First probe the map to see if we havecan open PFOW here */
+	lpddr = lpddr_probe_chip(map);
+	if (!lpddr)
+		return NULL;
+
+	map->fldrv_priv = lpddr;
+	mtd = lpddr_cmdset(map);
+	if (mtd) {
+		if (mtd->size > map->size) {
+			printk(KERN_WARNING "Reducing visibility of %ldKiB chip"
+				"to %ldKiB\n", (unsigned long)mtd->size >> 10,
+				(unsigned long)map->size >> 10);
+			mtd->size = map->size;
+		}
+		return mtd;
+	}
+
+	kfree(lpddr->qinfo);
+	kfree(lpddr);
+	map->fldrv_priv = NULL;
+	return NULL;
+}
+
+static struct mtd_chip_driver lpddr_chipdrv = {
+	.probe		= lpddr_probe,
+	.name		= "qinfo_probe",
+	.module		= THIS_MODULE
+};
+
+static int __init lpddr_probe_init(void)
+{
+	register_mtd_chip_driver(&lpddr_chipdrv);
+	return 0;
+}
+
+static void __exit lpddr_probe_exit(void)
+{
+	unregister_mtd_chip_driver(&lpddr_chipdrv);
+}
+
+module_init(lpddr_probe_init);
+module_exit(lpddr_probe_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Vasiliy Leonenko <vasiliy.leonenko@gmail.com>");
+MODULE_DESCRIPTION("Driver to probe qinfo flash chips");
+