Fix to avoid crash on BCM6358 platforms

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Merge tag 'mips-fixes_6.3_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux

Pull MIPS fix from Thomas Bogendoerfer:
 "Fix to avoid crash on BCM6358 platforms"

* tag 'mips-fixes_6.3_1' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  mips: bmips: BCM6358: disable RAC flush for TP1

arch/mips/bmips/dma.c

@@ -5,6 +5,8 @@
 #include <asm/bmips.h>
 #include <asm/io.h>
 
+bool bmips_rac_flush_disable;
+
 void arch_sync_dma_for_cpu_all(void)
 {
 	void __iomem *cbr = BMIPS_GET_CBR();
@@ -15,6 +17,9 @@ void arch_sync_dma_for_cpu_all(void)
 	    boot_cpu_type() != CPU_BMIPS4380)
 		return;
 
+	if (unlikely(bmips_rac_flush_disable))
+		return;
+
 	/* Flush stale data out of the readahead cache */
 	cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
 	__raw_writel(cfg | 0x100, cbr + BMIPS_RAC_CONFIG);

arch/mips/bmips/setup.c

@@ -35,6 +35,8 @@
 #define REG_BCM6328_OTP		((void __iomem *)CKSEG1ADDR(0x1000062c))
 #define BCM6328_TP1_DISABLED	BIT(9)
 
+extern bool bmips_rac_flush_disable;
+
 static const unsigned long kbase = VMLINUX_LOAD_ADDRESS & 0xfff00000;
 
 struct bmips_quirk {
@@ -104,6 +106,12 @@ static void bcm6358_quirks(void)
 	 * disable SMP for now
 	 */
 	bmips_smp_enabled = 0;
+
+	/*
+	 * RAC flush causes kernel panics on BCM6358 when booting from TP1
+	 * because the bootloader is not initializing it properly.
+	 */
+	bmips_rac_flush_disable = !!(read_c0_brcm_cmt_local() & (1 << 31));
 }
 
 static void bcm6368_quirks(void)