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

1 files changed, 26 insertions, 10 deletions

diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index fb866804820c..b4acc4f2074d 100644
--- a/drivers/edac/ghes_edac.c
+++ b/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;