[U-Boot] [PATCH v2] PPC405EX CHIP_21 erratum

[Steven A. Falco]

v2:
Correct checkpatch errors/warnings re: whitespace, comment style, etc.
Move PVR logic out of board config file.
Simplify ifdef structure.

APM errata CHIP_21 for the 405EX/EXr (from the rev 1.09 document dated
4/27/11) states that rev D processors may wake up with the wrong feature
set.  I've personally seen that happen.  This patch implements the
APM-proposed workaround.

To enable this patch for your board, add the appropriate define for your
CPU to your board header file.  See kilauea.h for an example.  The
following variants are supported:

#define CONFIG_SYS_4xx_CHIP_21_405EX_NO_SECURITY
#define CONFIG_SYS_4xx_CHIP_21_405EX_SECURITY
#define CONFIG_SYS_4xx_CHIP_21_405EXr_NO_SECURITY
#define CONFIG_SYS_4xx_CHIP_21_405EXr_SECURITY

Please note that if you select the wrong define, your board will not
boot, and JTAG will be required to recover.

Tested on custom board using CONFIG_SYS_4xx_CHIP_21_405EX_NO_SECURITY.

Signed-off-by: Steve Falco <sfalco at harris.com>

---

diff --git a/arch/powerpc/cpu/ppc4xx/cpu_init.c b/arch/powerpc/cpu/ppc4xx/cpu_init.c
index bf208ad..2f3a802 100644
--- a/arch/powerpc/cpu/ppc4xx/cpu_init.c
+++ b/arch/powerpc/cpu/ppc4xx/cpu_init.c
@@ -221,6 +221,66 @@ void reconfigure_pll(u32 new_cpu_freq)
 #endif
 }
 
+#ifdef CONFIG_SYS_4xx_CHIP_21_ERRATA
+void
+chip_21_errata(void)
+{
+	/*
+	 * See rev 1.09 of the 405EX/405EXr errata.  CHIP_21 says that
+	 * sometimes reading the PVR and/or SDR0_ECID results in incorrect
+	 * values.  Since the rev-D chip uses the SDR0_ECID bits to control
+	 * internal features, that means the second PCIe or ethernet of an EX
+	 * variant could fail to work.  Also, security features of both EX and
+	 * EXr might be incorrectly disabled.
+	 *
+	 * The suggested workaround is as follows (covering rev-C and rev-D):
+	 *
+	 * 1.Read the PVR and SDR0_ECID3.
+	 *
+	 * 2.If the PVR matches an expected Revision C PVR value AND if
+	 * SDR0_ECID3[12:15] is different from PVR[28:31], then – processor is
+	 * Revision C: continue executing the initialization code (no reset
+	 * required).  else – go to step 3.
+	 *
+	 * 3.If the PVR matches an expected Revision D PVR value AND if
+	 * SDR0_ECID3[10:11] matches its expected value, then – continue
+	 * executing initialization code, no reset required.  else – write
+	 * DBCR0[RST] = 0b11 to generate a SysReset.
+	 */
+
+	u32 pvr;
+	u32 pvr_28_31;
+	u32 ecid3;
+	u32 ecid3_10_11;
+	u32 ecid3_12_15;
+
+	/* Step 1: */
+	pvr = get_pvr();
+	mfsdr(SDR0_ECID3, ecid3);
+
+	/* Step 2: */
+	pvr_28_31 = pvr & 0xf;
+	ecid3_10_11 = (ecid3 >> 20) & 0x3;
+	ecid3_12_15 = (ecid3 >> 16) & 0xf;
+	if ((pvr == CONFIG_405EX_CHIP21_PVR_REV_C) &&
+			(pvr_28_31 != ecid3_12_15)) {
+		/* No reset required. */
+		return;
+	}
+
+	/* Step 3: */
+	if ((pvr == CONFIG_405EX_CHIP21_PVR_REV_D) &&
+			(ecid3_10_11 == CONFIG_405EX_CHIP21_ECID3_REV_D)) {
+		/* No reset required. */
+		return;
+	}
+
+	/* Reset required. */
+	__asm__ __volatile__ ("sync; isync");
+	mtspr(SPRN_DBCR0, 0x30000000);
+}
+#endif
+
 /*
  * Breath some life into the CPU...
  *
@@ -235,6 +295,10 @@ cpu_init_f (void)
 	u32 val;
 #endif
 
+#ifdef CONFIG_SYS_4xx_CHIP_21_ERRATA
+	chip_21_errata();
+#endif
+
 	reconfigure_pll(CONFIG_SYS_PLL_RECONFIG);
 
 #if (defined(CONFIG_405EP) || defined (CONFIG_405EX)) && \
diff --git a/arch/powerpc/include/asm/ppc405ex.h b/arch/powerpc/include/asm/ppc405ex.h
index 36d3149..8070385 100644
--- a/arch/powerpc/include/asm/ppc405ex.h
+++ b/arch/powerpc/include/asm/ppc405ex.h
@@ -43,6 +43,11 @@
 #define SDR0_PFC1		0x4101
 #define SDR0_MFR		0x4300	/* SDR0_MFR reg */
 
+#define SDR0_ECID0		0x0080
+#define SDR0_ECID1		0x0081
+#define SDR0_ECID2		0x0082
+#define SDR0_ECID3		0x0083
+
 #define SDR0_SDCS_SDD		(0x80000000 >> 31)
 
 #define SDR0_SRST_DMC		(0x80000000 >> 10)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h
index f5bf4dd..68f9868 100644
--- a/arch/powerpc/include/asm/processor.h
+++ b/arch/powerpc/include/asm/processor.h
@@ -974,6 +974,37 @@
 #define PVR_5200B	0x80822014
 
 /*
+ * CHIP_21 Errata
+ */
+#ifdef CONFIG_SYS_4xx_CHIP_21_405EX_SECURITY
+#define CONFIG_SYS_4xx_CHIP_21_ERRATA
+#define CONFIG_405EX_CHIP21_PVR_REV_C	PVR_405EX1_RC
+#define CONFIG_405EX_CHIP21_PVR_REV_D	PVR_405EX1_RD
+#define CONFIG_405EX_CHIP21_ECID3_REV_D	0x0
+#endif
+
+#ifdef CONFIG_SYS_4xx_CHIP_21_405EX_NO_SECURITY
+#define CONFIG_SYS_4xx_CHIP_21_ERRATA
+#define CONFIG_405EX_CHIP21_PVR_REV_C	PVR_405EX2_RC
+#define CONFIG_405EX_CHIP21_PVR_REV_D	PVR_405EX2_RD
+#define CONFIG_405EX_CHIP21_ECID3_REV_D	0x1
+#endif
+
+#ifdef CONFIG_SYS_4xx_CHIP_21_405EXr_SECURITY
+#define CONFIG_SYS_4xx_CHIP_21_ERRATA
+#define CONFIG_405EX_CHIP21_PVR_REV_C	PVR_405EXR1_RC
+#define CONFIG_405EX_CHIP21_PVR_REV_D	PVR_405EXR1_RD
+#define CONFIG_405EX_CHIP21_ECID3_REV_D	0x2
+#endif
+
+#ifdef CONFIG_SYS_4xx_CHIP_21_405EXr_NO_SECURITY
+#define CONFIG_SYS_4xx_CHIP_21_ERRATA
+#define CONFIG_405EX_CHIP21_PVR_REV_C	PVR_405EXR2_RC
+#define CONFIG_405EX_CHIP21_PVR_REV_D	PVR_405EXR2_RD
+#define CONFIG_405EX_CHIP21_ECID3_REV_D	0x3
+#endif
+
+/*
  * System Version Register
  */
 
diff --git a/include/configs/kilauea.h b/include/configs/kilauea.h
index 031f8fb..2be1104 100644
--- a/include/configs/kilauea.h
+++ b/include/configs/kilauea.h
@@ -44,6 +44,12 @@
 #endif
 
 /*
+ * CHIP_21 errata - you must set this to match your CPU, else the board
+ * will not boot.
+ */
+#define CONFIG_SYS_4xx_CHIP_21_405EX_NO_SECURITY
+
+/*
  * Include common defines/options for all AMCC eval boards
  */
 #define CONFIG_HOSTNAME		kilauea