[MTD] map driver for NOR flash on the Intel Vermilion Range chipset

The Vermilion Range Expansion Bus supports four chip selects, each of which
has 64MiB of address space.  The 2nd BAR of the Expansion Bus PCI Device
is a 256MiB memory region containing the address spaces for all four of
the chip selects, with start addresses hardcoded on 64MiB boundaries.

This map driver only supports NOR flash on chip select 0.  The buswidth
(either 8 bits or 16 bits) is determined by reading the Expansion Bus Timing
and Control Register for Chip Select 0 (EXP_TIMING_CS0).
Signed-off-by: Andy Lowe <alowe@mvista.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/maps/Kconfig

@@ -581,6 +581,13 @@ config MTD_SHARP_SL
 	help
 	  This enables access to the flash chip on the Sharp SL Series of PDAs.
 
+config MTD_INTEL_VR_NOR
+	tristate "NOR flash on Intel Vermilion Range Expansion Bus CS0"
+	depends on PCI
+	help
+	  Map driver for a NOR flash bank located on the Expansion Bus of the
+	  Intel Vermilion Range chipset.
+
 config MTD_PLATRAM
 	tristate "Map driver for platform device RAM (mtd-ram)"
 	select MTD_RAM

drivers/mtd/maps/Makefile

@@ -68,3 +68,4 @@ obj-$(CONFIG_MTD_SHARP_SL)	+= sharpsl-flash.o
 obj-$(CONFIG_MTD_PLATRAM)	+= plat-ram.o
 obj-$(CONFIG_MTD_OMAP_NOR)	+= omap_nor.o
 obj-$(CONFIG_MTD_MTX1)		+= mtx-1_flash.o
+obj-$(CONFIG_MTD_INTEL_VR_NOR)	+= intel_vr_nor.o

drivers/mtd/maps/intel_vr_nor.c

+/*
+ * drivers/mtd/maps/intel_vr_nor.c
+ *
+ * An MTD map driver for a NOR flash bank on the Expansion Bus of the Intel
+ * Vermilion Range chipset.
+ *
+ * The Vermilion Range Expansion Bus supports four chip selects, each of which
+ * has 64MiB of address space.  The 2nd BAR of the Expansion Bus PCI Device
+ * is a 256MiB memory region containing the address spaces for all four of the
+ * chip selects, with start addresses hardcoded on 64MiB boundaries.
+ *
+ * This map driver only supports NOR flash on chip select 0.  The buswidth
+ * (either 8 bits or 16 bits) is determined by reading the Expansion Bus Timing
+ * and Control Register for Chip Select 0 (EXP_TIMING_CS0).  This driver does
+ * not modify the value in the EXP_TIMING_CS0 register except to enable writing
+ * and disable boot acceleration.  The timing parameters in the register are
+ * assumed to have been properly initialized by the BIOS.  The reset default
+ * timing parameters are maximally conservative (slow), so access to the flash
+ * will be slower than it should be if the BIOS has not initialized the timing
+ * parameters.
+ *
+ * Author: Andy Lowe <alowe@mvista.com>
+ *
+ * 2006 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/cfi.h>
+#include <linux/mtd/flashchip.h>
+
+#define DRV_NAME "vr_nor"
+
+struct vr_nor_mtd {
+	void __iomem *csr_base;
+	struct map_info map;
+	struct mtd_info *info;
+	int nr_parts;
+	struct pci_dev *dev;
+};
+
+/* Expansion Bus Configuration and Status Registers are in BAR 0 */
+#define EXP_CSR_MBAR 0
+/* Expansion Bus Memory Window is BAR 1 */
+#define EXP_WIN_MBAR 1
+/* Maximum address space for Chip Select 0 is 64MiB */
+#define CS0_SIZE 0x04000000
+/* Chip Select 0 is at offset 0 in the Memory Window */
+#define CS0_START 0x0
+/* Chip Select 0 Timing Register is at offset 0 in CSR */
+#define EXP_TIMING_CS0 0x00
+#define TIMING_CS_EN		(1 << 31)	/* Chip Select Enable */
+#define TIMING_BOOT_ACCEL_DIS	(1 <<  8)	/* Boot Acceleration Disable */
+#define TIMING_WR_EN		(1 <<  1)	/* Write Enable */
+#define TIMING_BYTE_EN		(1 <<  0)	/* 8-bit vs 16-bit bus */
+#define TIMING_MASK		0x3FFF0000
+
+static void __devexit vr_nor_destroy_partitions(struct vr_nor_mtd *p)
+{
+	if (p->nr_parts > 0) {
+#if defined(CONFIG_MTD_PARTITIONS) || defined(CONFIG_MTD_PARTITIONS_MODULE)
+		del_mtd_partitions(p->info);
+#endif
+	} else
+		del_mtd_device(p->info);
+}
+
+static int __devinit vr_nor_init_partitions(struct vr_nor_mtd *p)
+{
+	int err = 0;
+#if defined(CONFIG_MTD_PARTITIONS) || defined(CONFIG_MTD_PARTITIONS_MODULE)
+	struct mtd_partition *parts;
+	static const char *part_probes[] = { "cmdlinepart", NULL };
+#endif
+
+	/* register the flash bank */
+#if defined(CONFIG_MTD_PARTITIONS) || defined(CONFIG_MTD_PARTITIONS_MODULE)
+	/* partition the flash bank */
+	p->nr_parts = parse_mtd_partitions(p->info, part_probes, &parts, 0);
+	if (p->nr_parts > 0)
+		err = add_mtd_partitions(p->info, parts, p->nr_parts);
+#endif
+	if (p->nr_parts <= 0)
+		err = add_mtd_device(p->info);
+
+	return err;
+}
+
+static void __devexit vr_nor_destroy_mtd_setup(struct vr_nor_mtd *p)
+{
+	map_destroy(p->info);
+}
+
+static int __devinit vr_nor_mtd_setup(struct vr_nor_mtd *p)
+{
+	static const char *probe_types[] =
+	    { "cfi_probe", "jedec_probe", NULL };
+	const char **type;
+
+	for (type = probe_types; !p->info && *type; type++)
+		p->info = do_map_probe(*type, &p->map);
+	if (!p->info)
+		return -ENODEV;
+
+	p->info->owner = THIS_MODULE;
+
+	return 0;
+}
+
+static void __devexit vr_nor_destroy_maps(struct vr_nor_mtd *p)
+{
+	unsigned int exp_timing_cs0;
+
+	/* write-protect the flash bank */
+	exp_timing_cs0 = readl(p->csr_base + EXP_TIMING_CS0);
+	exp_timing_cs0 &= ~TIMING_WR_EN;
+	writel(exp_timing_cs0, p->csr_base + EXP_TIMING_CS0);
+
+	/* unmap the flash window */
+	iounmap(p->map.virt);
+
+	/* unmap the csr window */
+	iounmap(p->csr_base);
+}
+
+/*
+ * Initialize the map_info structure and map the flash.
+ * Returns 0 on success, nonzero otherwise.
+ */
+static int __devinit vr_nor_init_maps(struct vr_nor_mtd *p)
+{
+	unsigned long csr_phys, csr_len;
+	unsigned long win_phys, win_len;
+	unsigned int exp_timing_cs0;
+	int err;
+
+	csr_phys = pci_resource_start(p->dev, EXP_CSR_MBAR);
+	csr_len = pci_resource_len(p->dev, EXP_CSR_MBAR);
+	win_phys = pci_resource_start(p->dev, EXP_WIN_MBAR);
+	win_len = pci_resource_len(p->dev, EXP_WIN_MBAR);
+
+	if (!csr_phys || !csr_len || !win_phys || !win_len)
+		return -ENODEV;
+
+	if (win_len < (CS0_START + CS0_SIZE))
+		return -ENXIO;
+
+	p->csr_base = ioremap_nocache(csr_phys, csr_len);
+	if (!p->csr_base)
+		return -ENOMEM;
+
+	exp_timing_cs0 = readl(p->csr_base + EXP_TIMING_CS0);
+	if (!(exp_timing_cs0 & TIMING_CS_EN)) {
+		dev_warn(&p->dev->dev, "Expansion Bus Chip Select 0 "
+		       "is disabled.\n");
+		err = -ENODEV;
+		goto release;
+	}
+	if ((exp_timing_cs0 & TIMING_MASK) == TIMING_MASK) {
+		dev_warn(&p->dev->dev, "Expansion Bus Chip Select 0 "
+		       "is configured for maximally slow access times.\n");
+	}
+	p->map.name = DRV_NAME;
+	p->map.bankwidth = (exp_timing_cs0 & TIMING_BYTE_EN) ? 1 : 2;
+	p->map.phys = win_phys + CS0_START;
+	p->map.size = CS0_SIZE;
+	p->map.virt = ioremap_nocache(p->map.phys, p->map.size);
+	if (!p->map.virt) {
+		err = -ENOMEM;
+		goto release;
+	}
+	simple_map_init(&p->map);
+
+	/* Enable writes to flash bank */
+	exp_timing_cs0 |= TIMING_BOOT_ACCEL_DIS | TIMING_WR_EN;
+	writel(exp_timing_cs0, p->csr_base + EXP_TIMING_CS0);
+
+	return 0;
+
+      release:
+	iounmap(p->csr_base);
+	return err;
+}
+
+static struct pci_device_id vr_nor_pci_ids[] = {
+	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x500D)},
+	{0,}
+};
+
+static void __devexit vr_nor_pci_remove(struct pci_dev *dev)
+{
+	struct vr_nor_mtd *p = pci_get_drvdata(dev);
+
+	pci_set_drvdata(dev, NULL);
+	vr_nor_destroy_partitions(p);
+	vr_nor_destroy_mtd_setup(p);
+	vr_nor_destroy_maps(p);
+	kfree(p);
+	pci_release_regions(dev);
+	pci_disable_device(dev);
+}
+
+static int __devinit
+vr_nor_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	struct vr_nor_mtd *p = NULL;
+	unsigned int exp_timing_cs0;
+	int err;
+
+	err = pci_enable_device(dev);
+	if (err)
+		goto out;
+
+	err = pci_request_regions(dev, DRV_NAME);
+	if (err)
+		goto disable_dev;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	err = -ENOMEM;
+	if (!p)
+		goto release;
+
+	p->dev = dev;
+
+	err = vr_nor_init_maps(p);
+	if (err)
+		goto release;
+
+	err = vr_nor_mtd_setup(p);
+	if (err)
+		goto destroy_maps;
+
+	err = vr_nor_init_partitions(p);
+	if (err)
+		goto destroy_mtd_setup;
+
+	pci_set_drvdata(dev, p);
+
+	return 0;
+
+      destroy_mtd_setup:
+	map_destroy(p->info);
+
+      destroy_maps:
+	/* write-protect the flash bank */
+	exp_timing_cs0 = readl(p->csr_base + EXP_TIMING_CS0);
+	exp_timing_cs0 &= ~TIMING_WR_EN;
+	writel(exp_timing_cs0, p->csr_base + EXP_TIMING_CS0);
+
+	/* unmap the flash window */
+	iounmap(p->map.virt);
+
+	/* unmap the csr window */
+	iounmap(p->csr_base);
+
+      release:
+	kfree(p);
+	pci_release_regions(dev);
+
+      disable_dev:
+	pci_disable_device(dev);
+
+      out:
+	return err;
+}
+
+static struct pci_driver vr_nor_pci_driver = {
+	.name = DRV_NAME,
+	.probe = vr_nor_pci_probe,
+	.remove = __devexit_p(vr_nor_pci_remove),
+	.id_table = vr_nor_pci_ids,
+};
+
+static int __init vr_nor_mtd_init(void)
+{
+	return pci_register_driver(&vr_nor_pci_driver);
+}
+
+static void __exit vr_nor_mtd_exit(void)
+{
+	pci_unregister_driver(&vr_nor_pci_driver);
+}
+
+module_init(vr_nor_mtd_init);
+module_exit(vr_nor_mtd_exit);
+
+MODULE_AUTHOR("Andy Lowe");
+MODULE_DESCRIPTION("MTD map driver for NOR flash on Intel Vermilion Range");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, vr_nor_pci_ids);