mpc85xx: pcie: Implement workaround for Erratum A007815

The read-only-write-enable bit is set by default and must be cleared
to prevent overwriting read-only registers.  This should be done
immediately after resetting the PCI Express controller.

Reviewed-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Signed-off-by: Tony O'Brien <tony.obrien@alliedtelesis.co.nz>
[York S: Move SYS_FSL_ERRATUM_A007815 to Kconfig]
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/mpc85xx/Kconfig b/arch/powerpc/cpu/mpc85xx/Kconfig
index b0f34b6..615d7e1 100644
--- a/arch/powerpc/cpu/mpc85xx/Kconfig
+++ b/arch/powerpc/cpu/mpc85xx/Kconfig
@@ -831,6 +831,7 @@
 	select SYS_FSL_ERRATUM_A006593
 	select SYS_FSL_ERRATUM_A007186
 	select SYS_FSL_ERRATUM_A007212
+	select SYS_FSL_ERRATUM_A007815
 	select SYS_FSL_ERRATUM_A007907
 	select SYS_FSL_ERRATUM_A009942
 	select SYS_FSL_ERRATUM_ESDHC111
@@ -893,6 +894,7 @@
 	select SYS_FSL_ERRATUM_A006593
 	select SYS_FSL_ERRATUM_A007186
 	select SYS_FSL_ERRATUM_A007798
+	select SYS_FSL_ERRATUM_A007815
 	select SYS_FSL_ERRATUM_A007907
 	select SYS_FSL_ERRATUM_A009942
 	select SYS_FSL_HAS_DDR3
@@ -1081,6 +1083,9 @@
 config SYS_FSL_ERRATUM_A007212
 	bool
 
+config SYS_FSL_ERRATUM_A007815
+	bool
+
 config SYS_FSL_ERRATUM_A007798
 	bool
 
diff --git a/arch/powerpc/cpu/mpc85xx/cmd_errata.c b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
index 822ae72..b8be596 100644
--- a/arch/powerpc/cpu/mpc85xx/cmd_errata.c
+++ b/arch/powerpc/cpu/mpc85xx/cmd_errata.c
@@ -333,6 +333,10 @@
 #ifdef CONFIG_SYS_FSL_ERRATUM_A007907
 	puts("Work-around for Erratum A007907 enabled\n");
 #endif
+#ifdef CONFIG_SYS_FSL_ERRATUM_A007815
+	puts("Work-around for Erratum A007815 enabled\n");
+#endif
+
 	return 0;
 }
 
diff --git a/arch/powerpc/include/asm/fsl_pci.h b/arch/powerpc/include/asm/fsl_pci.h
index 8bee8ca..cad341e 100644
--- a/arch/powerpc/include/asm/fsl_pci.h
+++ b/arch/powerpc/include/asm/fsl_pci.h
@@ -79,7 +79,9 @@
 	u32	pme_msg_dis;	/* 0x024 - PCIE PME & message disable register */
 	u32	pme_msg_int_en;	/* 0x028 - PCIE PME & message interrupt enable register */
 	u32	pm_command;	/* 0x02c - PCIE PM Command register */
-	char	res4[3016];	/*     (- #xbf8	 #x30)3016 */
+	char	res3[2188];	/*     (0x8bc - 0x30 = 2188) */
+	u32	dbi_ro_wr_en;	/* 0x8bc - DBI read only write enable reg */
+	char	res4[824];	/*     (0xbf8 - 0x8c0 = 824) */
 	u32	block_rev1;	/* 0xbf8 - PCIE Block Revision register 1 */
 	u32	block_rev2;	/* 0xbfc - PCIE Block Revision register 2 */