nand: Introduce CONFIG_SYS_NAND_SELF_INIT

This allows a driver to run code between nand_scan_ident() and
nand_scan_tail(), among other things.  See the additions to
doc/README.nand for details.

To allow a gradual transition, Boards that don't set
CONFIG_SYS_NAND_SELF_INIT will still be initialized the old way, but
new drivers should not require this, and existing drivers should be
converted when convenient.

Signed-off-by: Scott Wood <scottwood@freescale.com>

doc/README.nand

@@ -120,6 +120,68 @@ Configuration Options:
    CONFIG_SYS_NAND_MAX_CHIPS
       The maximum number of NAND chips per device to be supported.
 
+   CONFIG_SYS_NAND_SELF_INIT
+      Traditionally, glue code in drivers/mtd/nand/nand.c has driven
+      the initialization process -- it provides the mtd and nand
+      structs, calls a board init function for a specific device,
+      calls nand_scan(), and registers with mtd.
+
+      This arrangement does not provide drivers with the flexibility to
+      run code between nand_scan_ident() and nand_scan_tail(), or other
+      deviations from the "normal" flow.
+
+      If a board defines CONFIG_SYS_NAND_SELF_INIT, drivers/mtd/nand/nand.c
+      will make one call to board_nand_init(), with no arguments.  That
+      function is responsible for calling a driver init function for
+      each NAND device on the board, that performs all initialization
+      tasks except setting mtd->name, and registering with the rest of
+      U-Boot.  Those last tasks are accomplished by calling  nand_register()
+      on the new mtd device.
+
+      Example of new init to be added to the end of an existing driver
+      init:
+
+	/*
+	 * devnum is the device number to be used in nand commands
+	 * and in mtd->name.  Must be less than
+	 * CONFIG_SYS_NAND_MAX_DEVICE.
+	 */
+	mtd = &nand_info[devnum];
+
+	/* chip is struct nand_chip, and is now provided by the driver. */
+	mtd->priv = &chip;
+
+	/*
+	 * Fill in appropriate values if this driver uses these fields,
+	 * or uses the standard read_byte/write_buf/etc. functions from
+	 * nand_base.c that use these fields.
+	 */
+	chip.IO_ADDR_R = ...;
+	chip.IO_ADDR_W = ...;
+
+	if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_CHIPS, NULL))
+		error out
+
+	/*
+	 * Insert here any code you wish to run after the chip has been
+	 * identified, but before any other I/O is done.
+	 */
+
+	if (nand_scan_tail(mtd))
+		error out
+
+	if (nand_register(devnum))
+		error out
+
+      In addition to providing more flexibility to the driver, it reduces
+      the difference between a U-Boot driver and its Linux counterpart.
+      nand_init() is now reduced to calling board_nand_init() once, and
+      printing a size summary.  This should also make it easier to
+      transition to delayed NAND initialization.
+
+      Please convert your driver even if you don't need the extra
+      flexibility, so that one day we can eliminate the old mechanism.
+
 NOTE:
 =====
 

drivers/mtd/nand/nand.c

@@ -23,6 +23,7 @@
 
 #include <common.h>
 #include <nand.h>
+#include <errno.h>
 
 #ifndef CONFIG_SYS_NAND_BASE_LIST
 #define CONFIG_SYS_NAND_BASE_LIST { CONFIG_SYS_NAND_BASE }
@@ -31,63 +32,84 @@
 DECLARE_GLOBAL_DATA_PTR;
 
 int nand_curr_device = -1;
+
+
 nand_info_t nand_info[CONFIG_SYS_MAX_NAND_DEVICE];
 
+#ifndef CONFIG_SYS_NAND_SELF_INIT
 static struct nand_chip nand_chip[CONFIG_SYS_MAX_NAND_DEVICE];
 static ulong base_address[CONFIG_SYS_MAX_NAND_DEVICE] = CONFIG_SYS_NAND_BASE_LIST;
-
-static const char default_nand_name[] = "nand";
-static __attribute__((unused)) char dev_name[CONFIG_SYS_MAX_NAND_DEVICE][8];
-
-static void nand_init_chip(struct mtd_info *mtd, struct nand_chip *nand,
-			   ulong base_addr)
-{
-	int maxchips = CONFIG_SYS_NAND_MAX_CHIPS;
-	static int __attribute__((unused)) i = 0;
-
-	if (maxchips < 1)
-		maxchips = 1;
-	mtd->priv = nand;
-
-	nand->IO_ADDR_R = nand->IO_ADDR_W = (void  __iomem *)base_addr;
-	if (board_nand_init(nand) == 0) {
-		if (nand_scan(mtd, maxchips) == 0) {
-			if (!mtd->name)
-				mtd->name = (char *)default_nand_name;
-#ifdef CONFIG_NEEDS_MANUAL_RELOC
-			else
-				mtd->name += gd->reloc_off;
 #endif
 
+static char dev_name[CONFIG_SYS_MAX_NAND_DEVICE][8];
+
+static unsigned long total_nand_size; /* in kiB */
+
+/* Register an initialized NAND mtd device with the U-Boot NAND command. */
+int nand_register(int devnum)
+{
+	struct mtd_info *mtd;
+
+	if (devnum >= CONFIG_SYS_MAX_NAND_DEVICE)
+		return -EINVAL;
+
+	mtd = &nand_info[devnum];
+
+	sprintf(dev_name[devnum], "nand%d", devnum);
+	mtd->name = dev_name[devnum];
+
 #ifdef CONFIG_MTD_DEVICE
 	/*
 	 * Add MTD device so that we can reference it later
 	 * via the mtdcore infrastructure (e.g. ubi).
 	 */
-			sprintf(dev_name[i], "nand%d", i);
-			mtd->name = dev_name[i++];
 	add_mtd_device(mtd);
 #endif
-		} else
-			mtd->name = NULL;
-	} else {
-		mtd->name = NULL;
-		mtd->size = 0;
-	}
 
+	total_nand_size += mtd->size / 1024;
+
+	if (nand_curr_device == -1)
+		nand_curr_device = devnum;
+
+	return 0;
 }
 
+#ifndef CONFIG_SYS_NAND_SELF_INIT
+static void nand_init_chip(int i)
+{
+	struct mtd_info *mtd = &nand_info[i];
+	struct nand_chip *nand = &nand_chip[i];
+	ulong base_addr = base_address[i];
+	int maxchips = CONFIG_SYS_NAND_MAX_CHIPS;
+
+	if (maxchips < 1)
+		maxchips = 1;
+
+	mtd->priv = nand;
+	nand->IO_ADDR_R = nand->IO_ADDR_W = (void  __iomem *)base_addr;
+
+	if (board_nand_init(nand))
+		return;
+
+	if (nand_scan(mtd, maxchips))
+		return;
+
+	nand_register(i);
+}
+#endif
+
 void nand_init(void)
 {
+#ifdef CONFIG_SYS_NAND_SELF_INIT
+	board_nand_init();
+#else
 	int i;
-	unsigned int size = 0;
-	for (i = 0; i < CONFIG_SYS_MAX_NAND_DEVICE; i++) {
-		nand_init_chip(&nand_info[i], &nand_chip[i], base_address[i]);
-		size += nand_info[i].size / 1024;
-		if (nand_curr_device == -1)
-			nand_curr_device = i;
-	}
-	printf("%u MiB\n", size / 1024);
+
+	for (i = 0; i < CONFIG_SYS_MAX_NAND_DEVICE; i++)
+		nand_init_chip(i);
+#endif
+
+	printf("%lu MiB\n", total_nand_size / 1024);
 
 #ifdef CONFIG_SYS_NAND_SELECT_DEVICE
 	/*

include/nand.h

@@ -30,7 +30,12 @@ extern void nand_init(void);
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/nand.h>
 
+#ifdef CONFIG_SYS_NAND_SELF_INIT
+void board_nand_init(void);
+int nand_register(int devnum);
+#else
 extern int board_nand_init(struct nand_chip *nand);
+#endif
 
 typedef struct mtd_info nand_info_t;