[PATCH 1/8] LPDDR qinfo probing.

[Alexey Korolev]

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.pdf

Signed-off-by: Alexey Korolev <akorolev at infradead.org>
Acked-by: Jared Hulbert <jaredeh at gmail.com>
---

diff --git a/drivers/mtd/lpddr/qinfo_probe.c b/drivers/mtd/lpddr/qinfo_probe.c
new file mode 100644
index 0000000..475b728
--- /dev/null
+++ b/drivers/mtd/lpddr/qinfo_probe.c
@@ -0,0 +1,255 @@
+/*
+ * Probing flash chips with QINFO records.
+ * (C) 2008 Korolev Alexey <akorolev at infradead.org>
+ * (C) 2008 Vasiliy Leonenko <vasiliy.leonenko at 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 at gmail.com>");
+MODULE_DESCRIPTION("Driver to probe qinfo flash chips");
+