ghes_edac: Improve driver's printk messages

Provide a better infrastructure for printk's inside the driver:
	- use edac_dbg() for debug messages;
	- standardize the usage of pr_info();
	- provide warning about the risk of relying on this
	  driver.

While here, changes the size of a fake memory to 1 page. This is
as good or as bad as 1000 pages, but it is easier for userspace to
detect, as I don't expect that any machine implementing GHES would
provide just 1 page available ;)
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

Conflicts:
	drivers/edac/ghes_edac.c

drivers/edac/ghes_edac.c

@@ -9,12 +9,13 @@
  * Red Hat Inc. http://www.redhat.com
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <acpi/ghes.h>
 #include <linux/edac.h>
 #include <linux/dmi.h>
 #include "edac_core.h"
 
-#define GHES_PFX   "ghes_edac: "
 #define GHES_EDAC_REVISION " Ver: 1.0.0"
 
 struct ghes_edac_pvt {
@@ -27,6 +28,7 @@ static LIST_HEAD(ghes_reglist);
 static DEFINE_MUTEX(ghes_edac_lock);
 static int ghes_edac_mc_num;
 
+
 /* Memory Device - Type 17 of SMBIOS spec */
 struct memdev_dmi_entry {
 	u8 type;
@@ -98,7 +100,8 @@ static void ghes_edac_dmidecode(const struct dmi_header *dh, void *arg)
 						       dimm_fill->count, 0, 0);
 
 		if (entry->size == 0xffff) {
-			pr_info(GHES_PFX "Can't get dimm size\n");
+			pr_info("Can't get DIMM%i size\n",
+				dimm_fill->count);
 			dimm->nr_pages = MiB_TO_PAGES(32);/* Unknown */
 		} else if (entry->size == 0x7fff) {
 			dimm->nr_pages = MiB_TO_PAGES(entry->extended_size);
@@ -163,11 +166,11 @@ static void ghes_edac_dmidecode(const struct dmi_header *dh, void *arg)
 		 */
 
 		if (dimm->nr_pages) {
-			pr_info(GHES_PFX "DIMM%i: %s size = %d MB%s\n",
+			edac_dbg(1, "DIMM%i: %s size = %d MB%s\n",
 				dimm_fill->count, memory_type[dimm->mtype],
 				PAGES_TO_MiB(dimm->nr_pages),
 				(dimm->edac_mode != EDAC_NONE) ? "(ECC)" : "");
-			pr_info(GHES_PFX "\ttype %d, detail 0x%02x, width %d(total %d)\n",
+			edac_dbg(2, "\ttype %d, detail 0x%02x, width %d(total %d)\n",
 				entry->memory_type, entry->type_detail,
 				entry->total_width, entry->data_width);
 		}
@@ -261,12 +264,10 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	 * to avoid duplicated memory controller numbers
 	 */
 	mutex_lock(&ghes_edac_lock);
-	pr_info("ghes_edac#%d: allocating space for %d dimms\n",
-		ghes_edac_mc_num, num_dimm);
 	mci = edac_mc_alloc(ghes_edac_mc_num, ARRAY_SIZE(layers), layers,
 			    sizeof(*pvt));
 	if (!mci) {
-		pr_info(GHES_PFX "Can't allocate memory for EDAC data\n");
+		pr_info("Can't allocate memory for EDAC data\n");
 		mutex_unlock(&ghes_edac_lock);
 		return -ENOMEM;
 	}
@@ -286,6 +287,22 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	mci->ctl_name = "ghes_edac";
 	mci->dev_name = "ghes";
 
+	if (!ghes_edac_mc_num) {
+		if (!fake) {
+			pr_info("This EDAC driver relies on BIOS to enumerate memory and get error reports.\n");
+			pr_info("Unfortunately, not all BIOSes reflect the memory layout correctly.\n");
+			pr_info("So, the end result of using this driver varies from vendor to vendor.\n");
+			pr_info("If you find incorrect reports, please contact your hardware vendor\n");
+			pr_info("to correct its BIOS.\n");
+			pr_info("This system has %d DIMM sockets.\n",
+				num_dimm);
+		} else {
+			pr_info("This system has a very crappy BIOS: It doesn't even list the DIMMS.\n");
+			pr_info("Its SMBIOS info is wrong. It is doubtful that the error report would\n");
+			pr_info("work on such system. Use this driver with caution\n");
+		}
+	}
+
 	if (!fake) {
 		/*
 		 * Fill DIMM info from DMI for the memory controller #0
@@ -304,8 +321,7 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 		struct dimm_info *dimm = EDAC_DIMM_PTR(mci->layers, mci->dimms,
 						       mci->n_layers, 0, 0, 0);
 
-		pr_info(GHES_PFX "Crappy BIOS detected. Faking DIMM EDAC data\n");
-		dimm->nr_pages = 1000;
+		dimm->nr_pages = 1;
 		dimm->grain = 128;
 		dimm->mtype = MEM_UNKNOWN;
 		dimm->dtype = DEV_UNKNOWN;
@@ -314,7 +330,7 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 
 	rc = edac_mc_add_mc(mci);
 	if (rc < 0) {
-		pr_info(GHES_PFX "Can't register at EDAC core\n");
+		pr_info("Can't register at EDAC core\n");
 		edac_mc_free(mci);
 		mutex_unlock(&ghes_edac_lock);
 		return -ENODEV;