[PATCH 01/22] hw/block: m25p80: Add ISSI SPI flash support

[Bin Meng <bmeng.cn@gmail.com>]

From: Bin Meng <bin.meng@windriver.com>

This adds the ISSI SPI flash support. The number of dummy cycles in
fast read, fast read dual output and fast read quad output commands
is currently using the default 8. Per the datasheet [1], the number
of dummy cycles configurable, but this is not modeled.

For flash whose size is larger than 16 MiB, the sequence of 3-byte
address along with EXTADD bit in the bank address register (BAR) is
not supported. Currently we assume that guest software will alawys
use op codes with 4-byte address sequence. Fortunately this is the
case for both U-Boot and Linux.

[1] http://www.issi.com/WW/pdf/25LP-WP256.pdf

Signed-off-by: Bin Meng <bin.meng@windriver.com>
---

 hw/block/m25p80.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
index 844cabea21..8a62bc4bc4 100644
--- a/hw/block/m25p80.c
+++ b/hw/block/m25p80.c
@@ -411,6 +411,7 @@ typedef enum {
     MAN_NUMONYX,
     MAN_WINBOND,
     MAN_SST,
+    MAN_ISSI,
     MAN_GENERIC,
 } Manufacturer;
 
@@ -486,6 +487,8 @@ static inline Manufacturer get_man(Flash *s)
         return MAN_MACRONIX;
     case 0xBF:
         return MAN_SST;
+    case 0x9D:
+        return MAN_ISSI;
     default:
         return MAN_GENERIC;
     }
@@ -705,6 +708,9 @@ static void complete_collecting_data(Flash *s)
         case MAN_SPANSION:
             s->quad_enable = !!(s->data[1] & 0x02);
             break;
+        case MAN_ISSI:
+            s->quad_enable = extract32(s->data[0], 6, 1);
+            break;
         case MAN_MACRONIX:
             s->quad_enable = extract32(s->data[0], 6, 1);
             if (s->len > 1) {
@@ -897,6 +903,16 @@ static void decode_fast_read_cmd(Flash *s)
                                     SPANSION_DUMMY_CLK_LEN
                                     );
         break;
+    case MAN_ISSI:
+        /*
+         * The fast read instruction code is followed by address bytes and
+         * dummy cycles, transmitted via the SI line.
+         *
+         * The number of dummy cycles are configurable but this is currently
+         * unmodeled, hence the default value 8 is used.
+         */
+        s->needed_bytes += ((8 * 1) / 8);
+        break;
     default:
         break;
     }
@@ -936,6 +952,16 @@ static void decode_dio_read_cmd(Flash *s)
             break;
         }
         break;
+    case MAN_ISSI:
+        /*
+         * The fast read dual I/O instruction code is followed by address bytes
+         * and dummy cycles, transmitted via the IO1 and IO0 line.
+         *
+         * The number of dummy cycles are configurable but this is currently
+         * unmodeled, hence the default value 4 is used.
+         */
+        s->needed_bytes += ((4 * 2) / 8);
+        break;
     default:
         break;
     }
@@ -976,6 +1002,16 @@ static void decode_qio_read_cmd(Flash *s)
             break;
         }
         break;
+    case MAN_ISSI:
+        /*
+         * The fast read quad I/O instruction code is followed by address bytes
+         * and dummy cycles, transmitted via the IO3, IO2, IO1 and IO0 line.
+         *
+         * The number of dummy cycles are configurable but this is currently
+         * unmodeled, hence the default value 6 is used.
+         */
+        s->needed_bytes += ((6 * 4) / 8);
+        break;
     default:
         break;
     }
@@ -1134,7 +1170,7 @@ static void decode_new_cmd(Flash *s, uint32_t value)
 
     case RDSR:
         s->data[0] = (!!s->write_enable) << 1;
-        if (get_man(s) == MAN_MACRONIX) {
+        if (get_man(s) == MAN_MACRONIX || get_man(s) == MAN_ISSI) {
             s->data[0] |= (!!s->quad_enable) << 6;
         }
         if (get_man(s) == MAN_SST) {
-- 
2.25.1