PNP: add pnp_eisa_id_to_string()

Converting the EISA ID to a string is messy and error-prone, and
we might as well use the same code for ISAPNP and PNPBIOS.

PNPACPI uses the conversion done by the ACPI core with
acpi_ex_eisa_id_to_string().

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-By: Rene Herman <rene.herman@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

5 files changed, 43 insertions, 45 deletions

diff --git a/drivers/pnp/base.h b/drivers/pnp/base.h
index ba55b0623f7e..9af0a6c7dd41 100644
--- a/drivers/pnp/base.h
+++ b/drivers/pnp/base.h
@@ -1,5 +1,7 @@
 extern spinlock_t pnp_lock;
 void *pnp_alloc(long size);
+#define PNP_EISA_ID_MASK 0x7fffffff
+void pnp_eisa_id_to_string(u32 id, char *str);
 struct pnp_id *pnp_add_id(struct pnp_dev *dev, char *id);
 int pnp_interface_attach_device(struct pnp_dev *dev);
 void pnp_fixup_device(struct pnp_dev *dev);
diff --git a/drivers/pnp/isapnp/core.c b/drivers/pnp/isapnp/core.c
index 10cade831433..ccb04190044b 100644
--- a/drivers/pnp/isapnp/core.c
+++ b/drivers/pnp/isapnp/core.c
@@ -398,24 +398,6 @@ static void __init isapnp_skip_bytes(int count)
 }
 
 /*
- *  Parse EISA id.
- */
-static void isapnp_parse_id(struct pnp_dev *dev, unsigned short vendor,
-                            unsigned short device)
-{
-        char id[8];
-
-        sprintf(id, "%c%c%c%x%x%x%x",
-                'A' + ((vendor >> 2) & 0x3f) - 1,
-                'A' + (((vendor & 3) << 3) | ((vendor >> 13) & 7)) - 1,
-                'A' + ((vendor >> 8) & 0x1f) - 1,
-                (device >> 4) & 0x0f,
-                device & 0x0f, (device >> 12) & 0x0f, (device >> 8) & 0x0f);
-
-        pnp_add_id(dev, id);
-}
-
-/*
  *  Parse logical device tag.
  */
 static struct pnp_dev *__init isapnp_parse_device(struct pnp_card *card,
@@ -423,13 +405,17 @@ static struct pnp_dev *__init isapnp_parse_device(struct pnp_card *card,
 {
         unsigned char tmp[6];
         struct pnp_dev *dev;
+        u32 eisa_id;
+        char id[8];
 
         isapnp_peek(tmp, size);
         dev = kzalloc(sizeof(struct pnp_dev), GFP_KERNEL);
         if (!dev)
                 return NULL;
         dev->number = number;
-        isapnp_parse_id(dev, (tmp[1] << 8) | tmp[0], (tmp[3] << 8) | tmp[2]);
+        eisa_id = tmp[0] | tmp[1] << 8 | tmp[2] << 16 | tmp[3] << 24;
+        pnp_eisa_id_to_string(eisa_id, id);
+        pnp_add_id(dev, id);
         dev->regs = tmp[4];
         dev->card = card;
         if (size > 5)
@@ -619,6 +605,8 @@ static int __init isapnp_create_device(struct pnp_card *card,
         unsigned char type, tmp[17];
         struct pnp_option *option;
         struct pnp_dev *dev;
+        u32 eisa_id;
+        char id[8];
 
         if ((dev = isapnp_parse_device(card, size, number++)) == NULL)
                 return 1;
@@ -658,8 +646,10 @@ static int __init isapnp_create_device(struct pnp_card *card,
                 case _STAG_COMPATDEVID:
                         if (size == 4 && compat < DEVICE_COUNT_COMPATIBLE) {
                                 isapnp_peek(tmp, 4);
-                                isapnp_parse_id(dev, (tmp[1] << 8) | tmp[0],
-                                                (tmp[3] << 8) | tmp[2]);
+                                eisa_id = tmp[0] | tmp[1] << 8 |
+                                          tmp[2] << 16 | tmp[3] << 24;
+                                pnp_eisa_id_to_string(eisa_id, id);
+                                pnp_add_id(dev, id);
                                 compat++;
                                 size = 0;
                         }
diff --git a/drivers/pnp/pnpbios/core.c b/drivers/pnp/pnpbios/core.c
index 2d592aea0aa7..3ee5ed437385 100644
--- a/drivers/pnp/pnpbios/core.c
+++ b/drivers/pnp/pnpbios/core.c
@@ -332,7 +332,7 @@ static int __init insert_device(struct pnp_bios_node *node)
         if (!dev)
                 return -1;
 
-        pnpid32_to_pnpid(node->eisa_id, id);
+        pnp_eisa_id_to_string(node->eisa_id & PNP_EISA_ID_MASK, id);
         dev_id = pnp_add_id(dev, id);
         if (!dev_id) {
                 kfree(dev);
diff --git a/drivers/pnp/pnpbios/rsparser.c b/drivers/pnp/pnpbios/rsparser.c
index dbc88412c12e..948a661280d7 100644
--- a/drivers/pnp/pnpbios/rsparser.c
+++ b/drivers/pnp/pnpbios/rsparser.c
@@ -494,32 +494,12 @@ len_err:
  * Compatible Device IDs
  */
 
-#define HEX(id,a) hex[((id)>>a) & 15]
-#define CHAR(id,a) (0x40 + (((id)>>a) & 31))
-
-void pnpid32_to_pnpid(u32 id, char *str)
-{
-        const char *hex = "0123456789abcdef";
-
-        id = be32_to_cpu(id);
-        str[0] = CHAR(id, 26);
-        str[1] = CHAR(id, 21);
-        str[2] = CHAR(id, 16);
-        str[3] = HEX(id, 12);
-        str[4] = HEX(id, 8);
-        str[5] = HEX(id, 4);
-        str[6] = HEX(id, 0);
-        str[7] = '\0';
-}
-
-#undef CHAR
-#undef HEX
-
 static unsigned char *pnpbios_parse_compatible_ids(unsigned char *p,
                                                    unsigned char *end,
                                                    struct pnp_dev *dev)
 {
         int len, tag;
+        u32 eisa_id;
         char id[8];
         struct pnp_id *dev_id;
 
@@ -549,8 +529,8 @@ static unsigned char *pnpbios_parse_compatible_ids(unsigned char *p,
                 case SMALL_TAG_COMPATDEVID:     /* compatible ID */
                         if (len != 4)
                                 goto len_err;
-                        pnpid32_to_pnpid(p[1] | p[2] << 8 | p[3] << 16 | p[4] <<
-                                         24, id);
+                        eisa_id = p[1] | p[2] << 8 | p[3] << 16 | p[4] << 24;
+                        pnp_eisa_id_to_string(eisa_id & PNP_EISA_ID_MASK, id);
                         dev_id = pnp_add_id(dev, id);
                         if (!dev_id)
                                 return NULL;
diff --git a/drivers/pnp/support.c b/drivers/pnp/support.c
index 13c608f5fb30..e848b794e312 100644
--- a/drivers/pnp/support.c
+++ b/drivers/pnp/support.c
@@ -25,3 +25,29 @@ int pnp_is_active(struct pnp_dev *dev)
 }
 
 EXPORT_SYMBOL(pnp_is_active);
+
+/*
+ * Functionally similar to acpi_ex_eisa_id_to_string(), but that's
+ * buried in the ACPI CA, and we can't depend on it being present.
+ */
+void pnp_eisa_id_to_string(u32 id, char *str)
+{
+        id = be32_to_cpu(id);
+
+        /*
+         * According to the specs, the first three characters are five-bit
+         * compressed ASCII, and the left-over high order bit should be zero.
+         * However, the Linux ISAPNP code historically used six bits for the
+         * first character, and there seem to be IDs that depend on that,
+         * e.g., "nEC8241" in the Linux 8250_pnp serial driver and the
+         * FreeBSD sys/pc98/cbus/sio_cbus.c driver.
+         */
+        str[0] = 'A' + ((id >> 26) & 0x3f) - 1;
+        str[1] = 'A' + ((id >> 21) & 0x1f) - 1;
+        str[2] = 'A' + ((id >> 16) & 0x1f) - 1;
+        str[3] = hex_asc((id >> 12) & 0xf);
+        str[4] = hex_asc((id >>  8) & 0xf);
+        str[5] = hex_asc((id >>  4) & 0xf);
+        str[6] = hex_asc((id >>  0) & 0xf);
+        str[7] = '\0';
+}