[PATCH v4 10/21] ppc440_sdram: Implement enable bit in the DDR2 SDRAM

[BALATON Zoltan]

To allow removing the do_init hack we need to improve the DDR2 SDRAM
controller model to handle the enable/disable bit that it ignored so
far.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
---
v4: Add define for enable bit
v2: replace 0x08000000 with BIT(27)

 hw/ppc/ppc440_uc.c | 38 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/ppc440_uc.c b/hw/ppc/ppc440_uc.c
index 01184e717b..aa09534abb 100644
--- a/hw/ppc/ppc440_uc.c
+++ b/hw/ppc/ppc440_uc.c
@@ -23,6 +23,7 @@
 #include "sysemu/reset.h"
 #include "ppc440.h"
 #include "qom/object.h"
+#include "trace.h"
 
 /*****************************************************************************/
 /* L2 Cache as SRAM */
@@ -484,6 +485,7 @@ void ppc4xx_sdr_init(CPUPPCState *env)
 /* SDRAM controller */
 typedef struct ppc440_sdram_t {
     uint32_t addr;
+    uint32_t mcopt2;
     int nbanks;
     Ppc4xxSdramBank bank[4];
 } ppc440_sdram_t;
@@ -581,12 +583,15 @@ static void sdram_set_bcr(ppc440_sdram_t *sdram, int i,
 {
     if (sdram->bank[i].bcr & 1) {
         /* First unmap RAM if enabled */
+        trace_ppc4xx_sdram_unmap(sdram_base(sdram->bank[i].bcr),
+                                 sdram_size(sdram->bank[i].bcr));
         sdram_bank_unmap(&sdram->bank[i]);
     }
     sdram->bank[i].bcr = bcr & 0xffe0ffc1;
     sdram->bank[i].base = sdram_base(bcr);
     sdram->bank[i].size = sdram_size(bcr);
     if (enabled && (bcr & 1)) {
+        trace_ppc4xx_sdram_map(sdram_base(bcr), sdram_size(bcr));
         sdram_bank_map(&sdram->bank[i]);
     }
 }
@@ -596,7 +601,7 @@ static void sdram_map_bcr(ppc440_sdram_t *sdram)
     int i;
 
     for (i = 0; i < sdram->nbanks; i++) {
-        if (sdram->bank[i].size != 0) {
+        if (sdram->bank[i].size) {
             sdram_set_bcr(sdram, i, sdram_bcr(sdram->bank[i].base,
                                               sdram->bank[i].size), 1);
         } else {
@@ -605,6 +610,17 @@ static void sdram_map_bcr(ppc440_sdram_t *sdram)
     }
 }
 
+static void sdram_unmap_bcr(ppc440_sdram_t *sdram)
+{
+    int i;
+
+    for (i = 0; i < sdram->nbanks; i++) {
+        if (sdram->bank[i].size) {
+            sdram_set_bcr(sdram, i, sdram->bank[i].bcr & ~1, 0);
+        }
+    }
+}
+
 static uint32_t dcr_read_sdram(void *opaque, int dcrn)
 {
     ppc440_sdram_t *sdram = opaque;
@@ -636,7 +652,7 @@ static uint32_t dcr_read_sdram(void *opaque, int dcrn)
             ret = 0x80000000;
             break;
         case 0x21: /* SDRAM_MCOPT2 */
-            ret = 0x08000000;
+            ret = sdram->mcopt2;
             break;
         case 0x40: /* SDRAM_MB0CF */
             ret = 0x00008001;
@@ -658,6 +674,8 @@ static uint32_t dcr_read_sdram(void *opaque, int dcrn)
     return ret;
 }
 
+#define SDRAM_DDR2_MCOPT2_DCEN BIT(27)
+
 static void dcr_write_sdram(void *opaque, int dcrn, uint32_t val)
 {
     ppc440_sdram_t *sdram = opaque;
@@ -680,6 +698,21 @@ static void dcr_write_sdram(void *opaque, int dcrn, 
uint32_t val)
         switch (sdram->addr) {
         case 0x00: /* B0CR */
             break;
+        case 0x21: /* SDRAM_MCOPT2 */
+            if (!(sdram->mcopt2 & SDRAM_DDR2_MCOPT2_DCEN) &&
+                (val & SDRAM_DDR2_MCOPT2_DCEN)) {
+                trace_ppc4xx_sdram_enable("enable");
+                /* validate all RAM mappings */
+                sdram_map_bcr(sdram);
+                sdram->mcopt2 |= SDRAM_DDR2_MCOPT2_DCEN;
+            } else if ((sdram->mcopt2 & SDRAM_DDR2_MCOPT2_DCEN) &&
+                       !(val & SDRAM_DDR2_MCOPT2_DCEN)) {
+                trace_ppc4xx_sdram_enable("disable");
+                /* invalidate all RAM mappings */
+                sdram_unmap_bcr(sdram);
+                sdram->mcopt2 &= ~SDRAM_DDR2_MCOPT2_DCEN;
+            }
+            break;
         default:
             break;
         }
@@ -694,6 +727,7 @@ static void sdram_reset(void *opaque)
     ppc440_sdram_t *sdram = opaque;
 
     sdram->addr = 0;
+    sdram->mcopt2 = SDRAM_DDR2_MCOPT2_DCEN;
 }
 
 void ppc440_sdram_init(CPUPPCState *env, int nbanks,
-- 
2.30.4