Refine physical address mapping of flash chips

 - Create distinct functions for mapping and unmapping for flash chips.
 - Map only when needed: map before probing and unmap immediately
   after it. Map again when a single chip was probed successfully before
   taking any actual actions and clean up afterwards.
 - Map special function chip registers centrally together with flash space
   instead of within (some) probing methods after successful probes.
 - Save the used base addresses of the mappings in struct flashctx as well.
 - Do not try to (un)map the zero-sized chip definitions that are merely hacks.
   This also fixes the printing of wrong warnings for these chip definitions
   introduced in r1765.

Corresponding to flashrom svn r1847.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/flashrom.c b/flashrom.c
index 93b292b..01c1d03 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -479,6 +479,7 @@
 void programmer_unmap_flash_region(void *virt_addr, size_t len)
 {
 	programmer_table[programmer].unmap_flash_region(virt_addr, len);
+	msg_gspew("%s: unmapped 0x%0*" PRIxPTR "\n", __func__, PRIxPTR_WIDTH, (uintptr_t)virt_addr);
 }
 
 void chip_writeb(const struct flashctx *flash, uint8_t val, chipaddr addr)
@@ -528,14 +529,6 @@
 		programmer_table[programmer].delay(usecs);
 }
 
-void map_flash_registers(struct flashctx *flash)
-{
-	size_t size = flash->chip->total_size * 1024;
-	/* Flash registers live 4 MByte below the flash. */
-	/* FIXME: This is incorrect for nonstandard flashbase. */
-	flash->virtual_registers = (chipaddr)programmer_map_flash_region("flash chip registers", (0xFFFFFFFF - 0x400000 - size + 1), size);
-}
-
 int read_memmapped(struct flashctx *flash, uint8_t *buf, unsigned int start,
 		   int unsigned len)
 {
@@ -1052,12 +1045,64 @@
 	return limitexceeded;
 }
 
+void unmap_flash(struct flashctx *flash)
+{
+	if (flash->virtual_registers != (chipaddr)ERROR_PTR) {
+		programmer_unmap_flash_region((void *)flash->virtual_registers, flash->chip->total_size * 1024);
+		flash->physical_registers = 0;
+		flash->virtual_registers = (chipaddr)ERROR_PTR;
+	}
+
+	if (flash->virtual_memory != (chipaddr)ERROR_PTR) {
+		programmer_unmap_flash_region((void *)flash->virtual_memory, flash->chip->total_size * 1024);
+		flash->physical_memory = 0;
+		flash->virtual_memory = (chipaddr)ERROR_PTR;
+	}
+}
+
+int map_flash(struct flashctx *flash)
+{
+	/* Init pointers to the fail-safe state to distinguish them later from legit values. */
+	flash->virtual_memory = (chipaddr)ERROR_PTR;
+	flash->virtual_registers = (chipaddr)ERROR_PTR;
+
+	/* FIXME: This avoids mapping (and unmapping) of flash chip definitions with size 0.
+	 * These are used for various probing-related hacks that would not map successfully anyway and should be
+	 * removed ASAP. */
+	if (flash->chip->total_size == 0)
+		return 0;
+
+	const chipsize_t size = flash->chip->total_size * 1024;
+	uintptr_t base = flashbase ? flashbase : (0xffffffff - size + 1);
+	void *addr = programmer_map_flash_region(flash->chip->name, base, size);
+	if (addr == ERROR_PTR) {
+		msg_perr("Could not map flash chip %s at 0x%0*" PRIxPTR ".\n",
+			 flash->chip->name, PRIxPTR_WIDTH, base);
+		return 1;
+	}
+	flash->physical_memory = base;
+	flash->virtual_memory = (chipaddr)addr;
+
+	/* FIXME: Special function registers normally live 4 MByte below flash space, but it might be somewhere
+	 * completely different on some chips and programmers, or not mappable at all.
+	 * Ignore these problems for now and always report success. */
+	if (flash->chip->feature_bits & FEATURE_REGISTERMAP) {
+		base = 0xffffffff - size - 0x400000 + 1;
+		addr = programmer_map_flash_region("flash chip registers", base, size);
+		if (addr == ERROR_PTR) {
+			msg_pdbg2("Could not map flash chip registers %s at 0x%0*" PRIxPTR ".\n",
+				 flash->chip->name, PRIxPTR_WIDTH, base);
+			return 0;
+		}
+		flash->physical_registers = base;
+		flash->virtual_registers = (chipaddr)addr;
+	}
+	return 0;
+}
+
 int probe_flash(struct registered_master *mst, int startchip, struct flashctx *flash, int force)
 {
 	const struct flashchip *chip;
-	unsigned long base = 0;
-	char location[64];
-	uint32_t size;
 	enum chipbustype buses_common;
 	char *tmp;
 
@@ -1082,9 +1127,8 @@
 		memcpy(flash->chip, chip, sizeof(struct flashchip));
 		flash->mst = mst;
 
-		size = flash->chip->total_size * 1024;
-		base = flashbase ? flashbase : (0xffffffff - size + 1);
-		flash->virtual_memory = (chipaddr)programmer_map_flash_region("flash chip", base, size);
+		if (map_flash(flash) != 0)
+			return -1;
 
 		/* We handle a forced match like a real match, we just avoid probing. Note that probe_flash()
 		 * is only called with force=1 after normal probing failed.
@@ -1133,8 +1177,7 @@
 			break;
 		/* Not the first flash chip detected on this bus, and it's just a generic match. Ignore it. */
 notfound:
-		programmer_unmap_flash_region((void *)flash->virtual_memory, size);
-		flash->virtual_memory = (chipaddr)NULL;
+		unmap_flash(flash);
 		free(flash->chip);
 		flash->chip = NULL;
 	}
@@ -1142,25 +1185,28 @@
 	if (!flash->chip)
 		return -1;
 
-#if CONFIG_INTERNAL == 1
-	if (programmer_table[programmer].map_flash_region == physmap)
-		snprintf(location, sizeof(location), "at physical address 0x%lx", base);
-	else
-#endif
-		snprintf(location, sizeof(location), "on %s", programmer_table[programmer].name);
 
 	tmp = flashbuses_to_text(flash->chip->bustype);
-	msg_cinfo("%s %s flash chip \"%s\" (%d kB, %s) %s.\n", force ? "Assuming" : "Found",
-		  flash->chip->vendor, flash->chip->name, flash->chip->total_size, tmp, location);
+	msg_cinfo("%s %s flash chip \"%s\" (%d kB, %s) ", force ? "Assuming" : "Found",
+		  flash->chip->vendor, flash->chip->name, flash->chip->total_size, tmp);
 	free(tmp);
+#if CONFIG_INTERNAL == 1
+	if (programmer_table[programmer].map_flash_region == physmap)
+		msg_cinfo("mapped at physical address 0x%0*" PRIxPTR ".\n",
+			  PRIxPTR_WIDTH, flash->physical_memory);
+	else
+#endif
+		msg_cinfo("on %s.\n", programmer_table[programmer].name);
 
-	/* Flash registers will not be mapped if the chip was forced. Lock info
-	 * may be stored in registers, so avoid lock info printing.
-	 */
+	/* Flash registers may more likely not be mapped if the chip was forced.
+	 * Lock info may be stored in registers, so avoid lock info printing. */
 	if (!force)
 		if (flash->chip->printlock)
 			flash->chip->printlock(flash);
 
+	/* Get out of the way for later runs. */
+	unmap_flash(flash);
+
 	/* Return position of matching chip. */
 	return chip - flashchips;
 }