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master read fix mpc8245

PATCH New Marc Leeman 3 participants 3 messages May 11, 2004 – Jul 13, 2004

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Marc Leeman

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#0 lore raw

PATCH 1/1 master read fix mpc8245

Reading PPC Memory from another device with the PPC as PCI target device corrupts data due to interenal hardware buffering. Fix to disable these buffers with no performance influence.

a detailed description is available upon request (pdf, mailinglist bounces).

-------------- next part --------------

cpu/mpc824x/cpu_init.c +18 -0
@@ -102,7 +102,25 @@ cpu_init_f (void)
     CONFIG_WRITE_BYTE(AMBOR, val & 0xDF);
     CONFIG_WRITE_BYTE(AMBOR, val | 0x20);
     CONFIG_WRITE_BYTE(AMBOR, val & 0xDF);
+#ifdef CONFIG_MPC8245
+    /* silicon bug 28 MPC8245 */
+    CONFIG_READ_BYTE(AMBOR,val);
+    CONFIG_WRITE_BYTE(AMBOR,val|0x1);
+
+    CONFIG_READ_BYTE(PCMBCR,val);
+    /* in order not to corrupt data which is being read over the PCI bus
+     * with the PPC as master, we need to reduce the number of PCMRBs to 1,
+     * 4.11 in the  processor user manual 
+     * */
 
+#if 1
+    CONFIG_WRITE_BYTE(PCMBCR,(val|0xC0)); /* 1 PCMRB */
+#else
+    CONFIG_WRITE_BYTE(PCMBCR,(val|0x80)); /* 2 PCMRBs */
+    CONFIG_WRITE_BYTE(PCMBCR,(val|0x40)); /* 3 PCMRBs */
+#endif
+#endif
+    
     CONFIG_READ_WORD(PICR1, val);
 #if defined(CONFIG_MPC8240)
     CONFIG_WRITE_WORD( PICR1,

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include/mpc824x.h +1 -0
@@ -297,6 +297,7 @@
 #define PBESR		0x800000c7  /* PCI Bus Error Status Register */
 #define PBEAR		0x800000c8  /* Processor/PCI Bus Error Status Register */
 #define AMBOR		0x800000e0  /* Address Map B Options Register */
+#define PCMBCR		0x800000e1  /* PCI/Memory Buffer Copnfiguration */				       
 #define MCCR1		0x800000f0  /* Memory Control Configuration Register 1 */
 #define MCCR2		0x800000f4  /* Memory Control Configuration Register 2 */
 #define MCCR3		0x800000f8  /* Memory Control Configuration Register 3 */

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#1 lore raw

PATCH 1/1 master read fix mpc8245

Quoted 4 lines · In message <[email protected]> you wrote:

Reading PPC Memory from another device with the PPC as PCI target device corrupts data due to interenal hardware buffering. Fix to disable these buffers with no performance influence.

Thanks. [To be added later.]

Quoted 2 lines

a detailed description is available upon request (pdf, mailinglist bounces).

Please send a _plain_text_ version to me and/or this list so we can add it to the doc/ directory if necessary.

Thanks.

Best regards,

Wolfgang Denk

Signature · 5 lines
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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fatness  of  a  pig  is more or less green than the designated hitter
rule."                                               - David Guaspari
#2 lore raw

PATCH 1/1 master read fix mpc8245

In reply to Marc Leeman

Hello,

It seams that the second part of this patch is missing from current CVS thus MPC8245 cannot be compiled.

While we are on it can somebody tell me were PCMBCR register (0x800000e1) is documented?

Quoted 40 lines · Marc Leeman

Reading PPC Memory from another device with the PPC as PCI target device corrupts data due to interenal hardware buffering. Fix to disable these buffers with no performance influence.

a detailed description is available upon request (pdf, mailinglist bounces).

cpu/mpc824x/cpu_init.c +18 -0
@@ -102,7 +102,25 @@ cpu_init_f (void)
     CONFIG_WRITE_BYTE(AMBOR, val & 0xDF);
     CONFIG_WRITE_BYTE(AMBOR, val | 0x20);
     CONFIG_WRITE_BYTE(AMBOR, val & 0xDF);
+#ifdef CONFIG_MPC8245
+    /* silicon bug 28 MPC8245 */
+    CONFIG_READ_BYTE(AMBOR,val);
+    CONFIG_WRITE_BYTE(AMBOR,val|0x1);
+
+    CONFIG_READ_BYTE(PCMBCR,val);
+    /* in order not to corrupt data which is being read over the PCI bus
+     * with the PPC as master, we need to reduce the number of PCMRBs to 1,
+     * 4.11 in the  processor user manual 
+     * */
 
+#if 1
+    CONFIG_WRITE_BYTE(PCMBCR,(val|0xC0)); /* 1 PCMRB */
+#else
+    CONFIG_WRITE_BYTE(PCMBCR,(val|0x80)); /* 2 PCMRBs */
+    CONFIG_WRITE_BYTE(PCMBCR,(val|0x40)); /* 3 PCMRBs */
+#endif
+#endif
+    
     CONFIG_READ_WORD(PICR1, val);
 #if defined(CONFIG_MPC8240)
     CONFIG_WRITE_WORD( PICR1,

include/mpc824x.h line 303

Quoted 7 lines
include/mpc824x.h +1 -0
@@ -297,6 +297,7 @@
 #define PBESR		0x800000c7  /* PCI Bus Error Status Register */
 #define PBEAR		0x800000c8  /* Processor/PCI Bus Error Status Register */
 #define AMBOR		0x800000e0  /* Address Map B Options Register */
+#define PCMBCR		0x800000e1  /* PCI/Memory Buffer Copnfiguration */				       
 #define MCCR1		0x800000f0  /* Memory Control Configuration Register 1 */
 #define MCCR2		0x800000f4  /* Memory Control Configuration Register 2 */
 #define MCCR3		0x800000f8  /* Memory Control Configuration Register 3 */

--
Gleb.