Re: [PATCH 10/20] ppc440_sdram: Implement enable bit in the DDR2 SDRAM controller

[Cédric Le Goater]

On 8/19/22 18:55, BALATON Zoltan wrote:

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 <bala...@eik.bme.hu>
---
  hw/ppc/ppc440_uc.c | 34 ++++++++++++++++++++++++++++++++--
  1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/ppc440_uc.c b/hw/ppc/ppc440_uc.c
index c33f91e134..7c1513ff69 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;
@@ -680,6 +696,19 @@ 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 & 0x08000000) && (val & 0x08000000)) {
+                trace_ppc4xx_sdram_enable("enable");
+                /* validate all RAM mappings */
+                sdram_map_bcr(sdram);
+                sdram->mcopt2 |= 0x08000000;
+            } else if ((sdram->mcopt2 & 0x08000000) && !(val & 0x08000000)) {
+                trace_ppc4xx_sdram_enable("disable");
+                /* invalidate all RAM mappings */
+                sdram_unmap_bcr(sdram);
+                sdram->mcopt2 &= ~0x08000000;
+            }
+            break;
          default:
              break;
          }
@@ -694,6 +723,7 @@ static void sdram_reset(void *opaque)
      ppc440_sdram_t *sdram = opaque;

sdram->addr = 0;

+    sdram->mcopt2 = 0x08000000;

Introducing a define for the 0x08000000 value would make the code easier
to read.

Thanks,

C.

  }

void ppc440_sdram_init(CPUPPCState *env, int nbanks,