com32/disk: Code cleanup at disk_write_sectors and disk_read_sectors.

Pulled common code out of these functions into new ones.
The functions chs_setup and ebios_setup were created for this purpose.

Signed-off-by: Raphael S.Carvalho <raphael.scarv@gmail.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

diff --git a/com32/include/syslinux/disk.h b/com32/include/syslinux/disk.h
index f96ca68..b8361fe 100644 (file)
--- a/com32/include/syslinux/disk.h
+++ b/com32/include/syslinux/disk.h
@@ -41,6 +41,13 @@
 
 #define SECTOR 512u            /* bytes/sector */
 
+enum disk_op_codes {
+    EBIOS_READ_CODE = 0x42, /* Extended read */
+    EBIOS_WRITE_CODE = 0x43, /* Extended write */
+    CHS_READ_CODE = 0x02,
+    CHS_WRITE_CODE = 0x03,
+};
+
 struct disk_info {
     int disk;
     int ebios;                 /* EBIOS supported on this disk */

diff --git a/com32/lib/syslinux/disk.c b/com32/lib/syslinux/disk.c
index 093751a..0b0c737 100644 (file)
--- a/com32/lib/syslinux/disk.c
+++ b/com32/lib/syslinux/disk.c
@@ -33,6 +33,7 @@
  * Deal with disks and partitions
  */
 
+#include <core.h>
 #include <dprintf.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -158,6 +159,83 @@ out:
 }
 
 /**
+ * Fill inreg based on EBIOS addressing properties.
+ *
+ * @v diskinfo                 The disk drive to read from
+ * @v inreg                    Register data structure to be filled.
+ * @v lba                      The logical block address to begin reading at
+ * @v count                    The number of sectors to read
+ * @v op_code                  Code to write/read operation
+ * @ret                        lmalloc'd buf upon success, NULL upon failure
+ */
+static void *ebios_setup(const struct disk_info *const diskinfo, com32sys_t *inreg,
+                        uint64_t lba, uint8_t count, uint8_t op_code)
+{
+    static __lowmem struct disk_ebios_dapa dapa;
+    void *buf;
+
+    buf = lmalloc(count * diskinfo->bps);
+    if (!buf)
+       return NULL;
+
+    dapa.len = sizeof(dapa);
+    dapa.count = count;
+    dapa.off = OFFS(buf);
+    dapa.seg = SEG(buf);
+    dapa.lba = lba;
+
+    inreg->eax.b[1] = op_code;
+    inreg->esi.w[0] = OFFS(&dapa);
+    inreg->ds = SEG(&dapa);
+    inreg->edx.b[0] = diskinfo->disk;
+
+    return buf;
+}
+
+/**
+ * Fill inreg based on CHS addressing properties.
+ *
+ * @v diskinfo                 The disk drive to read from
+ * @v inreg                    Register data structure to be filled.
+ * @v lba                      The logical block address to begin reading at
+ * @v count                    The number of sectors to read
+ * @v op_code                  Code to write/read operation
+ * @ret                        lmalloc'd buf upon success, NULL upon failure
+ */
+static void *chs_setup(const struct disk_info *const diskinfo, com32sys_t *inreg,
+                      uint64_t lba, uint8_t count, uint8_t op_code)
+{
+    unsigned int c, h, s, t;
+    void *buf;
+
+    buf = lmalloc(count * diskinfo->bps);
+    if (!buf)
+       return NULL;
+
+    /*
+     * if we passed lba + count check and we get here, that means that
+     * lbacnt was calculated from chs geometry (or faked from 1/1/1), thus
+     * 32bits are perfectly enough and lbacnt corresponds to cylinder
+     * boundary
+     */
+    s = lba % diskinfo->spt;
+    t = lba / diskinfo->spt;
+    h = t % diskinfo->head;
+    c = t / diskinfo->head;
+
+    inreg->eax.b[0] = count;
+    inreg->eax.b[1] = op_code;
+    inreg->ecx.b[1] = c;
+    inreg->ecx.b[0] = ((c & 0x300) >> 2) | (s+1);
+    inreg->edx.b[1] = h;
+    inreg->edx.b[0] = diskinfo->disk;
+    inreg->ebx.w[0] = OFFS(buf);
+    inreg->es = SEG(buf);
+
+    return buf;
+}
+
+/**
  * Get disk block(s) and return a malloc'd buffer.
  *
  * @v diskinfo                 The disk drive to read from
@@ -172,7 +250,6 @@ void *disk_read_sectors(const struct disk_info *const diskinfo, uint64_t lba,
                        uint8_t count)
 {
     com32sys_t inreg;
-    struct disk_ebios_dapa *dapa;
     void *buf;
     void *data = NULL;
     uint32_t maxcnt;
@@ -184,48 +261,14 @@ void *disk_read_sectors(const struct disk_info *const diskinfo, uint64_t lba,
 
     memset(&inreg, 0, sizeof inreg);
 
-    buf = lmalloc(count * diskinfo->bps);
+    if (diskinfo->ebios)
+       buf = ebios_setup(diskinfo, &inreg, lba, count, EBIOS_READ_CODE);
+    else
+       buf = chs_setup(diskinfo, &inreg, lba, count, CHS_READ_CODE);
+
     if (!buf)
        return NULL;
 
-    dapa = lmalloc(sizeof(*dapa));
-    if (!dapa)
-       goto out;
-
-    if (diskinfo->ebios) {
-       dapa->len = sizeof(*dapa);
-       dapa->count = count;
-       dapa->off = OFFS(buf);
-       dapa->seg = SEG(buf);
-       dapa->lba = lba;
-
-       inreg.esi.w[0] = OFFS(dapa);
-       inreg.ds = SEG(dapa);
-       inreg.edx.b[0] = diskinfo->disk;
-       inreg.eax.b[1] = 0x42;  /* Extended read */
-    } else {
-       unsigned int c, h, s, t;
-       /*
-        * if we passed lba + count check and we get here, that means that
-        * lbacnt was calculated from chs geometry (or faked from 1/1/1), thus
-        * 32bits are perfectly enough and lbacnt corresponds to cylinder
-        * boundary
-        */
-       s = lba % diskinfo->spt;
-       t = lba / diskinfo->spt;
-       h = t % diskinfo->head;
-       c = t / diskinfo->head;
-
-       inreg.eax.b[0] = count;
-       inreg.eax.b[1] = 0x02;  /* Read */
-       inreg.ecx.b[1] = c;
-       inreg.ecx.b[0] = ((c & 0x300) >> 2) | (s+1);
-       inreg.edx.b[1] = h;
-       inreg.edx.b[0] = diskinfo->disk;
-       inreg.ebx.w[0] = OFFS(buf);
-       inreg.es = SEG(buf);
-    }
-
     if (disk_int13_retry(&inreg, NULL))
        goto out;
 
@@ -233,7 +276,6 @@ void *disk_read_sectors(const struct disk_info *const diskinfo, uint64_t lba,
     if (data)
        memcpy(data, buf, count * diskinfo->bps);
 out:
-    lfree(dapa);
     lfree(buf);
     return data;
 }
@@ -254,7 +296,6 @@ int disk_write_sectors(const struct disk_info *const diskinfo, uint64_t lba,
                       const void *data, uint8_t count)
 {
     com32sys_t inreg;
-    struct disk_ebios_dapa *dapa;
     void *buf;
     uint32_t maxcnt;
     uint32_t size = 65536;
@@ -264,57 +305,23 @@ int disk_write_sectors(const struct disk_info *const diskinfo, uint64_t lba,
     if (!count || count > maxcnt || lba + count > diskinfo->lbacnt)
        return -1;
 
-    buf = lmalloc(count * diskinfo->bps);
+    memset(&inreg, 0, sizeof inreg);
+
+    if (diskinfo->ebios)
+       buf = ebios_setup(diskinfo, &inreg, lba, count, EBIOS_WRITE_CODE);
+    else
+       buf = chs_setup(diskinfo, &inreg, lba, count, CHS_WRITE_CODE);
+
     if (!buf)
        return -1;
 
     memcpy(buf, data, count * diskinfo->bps);
-    memset(&inreg, 0, sizeof inreg);
-
-    dapa = lmalloc(sizeof(*dapa));
-    if (!dapa)
-       goto out;
-
-    if (diskinfo->ebios) {
-       dapa->len = sizeof(*dapa);
-       dapa->count = count;
-       dapa->off = OFFS(buf);
-       dapa->seg = SEG(buf);
-       dapa->lba = lba;
-
-       inreg.esi.w[0] = OFFS(dapa);
-       inreg.ds = SEG(dapa);
-       inreg.edx.b[0] = diskinfo->disk;
-       inreg.eax.b[1] = 0x43;  /* Extended write */
-    } else {
-       unsigned int c, h, s, t;
-       /*
-        * if we passed lba + count check and we get here, that means that
-        * lbacnt was calculated from chs geometry (or faked from 1/1/1), thus
-        * 32bits are perfectly enough and lbacnt corresponds to cylinder
-        * boundary
-        */
-       s = lba % diskinfo->spt;
-       t = lba / diskinfo->spt;
-       h = t % diskinfo->head;
-       c = t / diskinfo->head;
-
-       inreg.eax.b[0] = count;
-       inreg.eax.b[1] = 0x03;  /* Write */
-       inreg.ecx.b[1] = c;
-       inreg.ecx.b[0] = ((c & 0x300) >> 2) | (s+1);
-       inreg.edx.b[1] = h;
-       inreg.edx.b[0] = diskinfo->disk;
-       inreg.ebx.w[0] = OFFS(buf);
-       inreg.es = SEG(buf);
-    }
 
     if (disk_int13_retry(&inreg, NULL))
        goto out;
 
     rv = 0;                    /* ok */
 out:
-    lfree(dapa);
     lfree(buf);
     return rv;
 }