mips: bmips: rework and cache CBR addr handling

Rework the handling of the CBR address and cache it. This address
doesn't change and can be cached instead of reading the register every
time.

This is in preparation of permitting to tweak the CBR address in DT with
broken SoC or bootloader.

bmips_cbr_addr is defined in setup.c for each arch to keep compatibility
with legacy brcm47xx/brcm63xx and generic BMIPS target.

Acked-by: Florian Fainelli <[email protected]>
Signed-off-by: Christian Marangi <[email protected]>
Signed-off-by: Thomas Bogendoerfer <[email protected]>

Author: Ansuel

arch/mips/bcm47xx/prom.c

@@ -32,6 +32,7 @@
 #include <linux/ssb/ssb_driver_chipcommon.h>
 #include <linux/ssb/ssb_regs.h>
 #include <linux/smp.h>
+#include <asm/bmips.h>
 #include <asm/bootinfo.h>
 #include <bcm47xx.h>
 #include <bcm47xx_board.h>
@@ -110,6 +111,8 @@ static __init void prom_init_mem(void)
 
 void __init prom_init(void)
 {
+	/* Cache CBR addr before CPU/DMA setup */
+	bmips_cbr_addr = BMIPS_GET_CBR();
 	prom_init_mem();
 	setup_8250_early_printk_port(CKSEG1ADDR(BCM47XX_SERIAL_ADDR), 0, 0);
 }

arch/mips/bcm47xx/setup.c

@@ -37,6 +37,7 @@
 #include <linux/ssb/ssb.h>
 #include <linux/ssb/ssb_embedded.h>
 #include <linux/bcma/bcma_soc.h>
+#include <asm/bmips.h>
 #include <asm/bootinfo.h>
 #include <asm/idle.h>
 #include <asm/prom.h>
@@ -45,6 +46,9 @@
 #include <bcm47xx.h>
 #include <bcm47xx_board.h>
 
+/* CBR addr doesn't change and we can cache it */
+void __iomem *bmips_cbr_addr __read_mostly;
+
 union bcm47xx_bus bcm47xx_bus;
 EXPORT_SYMBOL(bcm47xx_bus);
 

arch/mips/bcm63xx/prom.c

@@ -22,6 +22,9 @@ void __init prom_init(void)
 {
 	u32 reg, mask;
 
+	/* Cache CBR addr before CPU/DMA setup */
+	bmips_cbr_addr = BMIPS_GET_CBR();
+
 	bcm63xx_cpu_init();
 
 	/* stop any running watchdog */

arch/mips/bcm63xx/setup.c

@@ -12,6 +12,7 @@
 #include <linux/memblock.h>
 #include <linux/ioport.h>
 #include <linux/pm.h>
+#include <asm/bmips.h>
 #include <asm/bootinfo.h>
 #include <asm/time.h>
 #include <asm/reboot.h>
@@ -22,6 +23,9 @@
 #include <bcm63xx_io.h>
 #include <bcm63xx_gpio.h>
 
+/* CBR addr doesn't change and we can cache it */
+void __iomem *bmips_cbr_addr __read_mostly;
+
 void bcm63xx_machine_halt(void)
 {
 	pr_info("System halted\n");

arch/mips/bmips/dma.c

@@ -9,7 +9,7 @@ bool bmips_rac_flush_disable;
 
 void arch_sync_dma_for_cpu_all(void)
 {
-	void __iomem *cbr = BMIPS_GET_CBR();
+	void __iomem *cbr = bmips_cbr_addr;
 	u32 cfg;
 
 	if (boot_cpu_type() != CPU_BMIPS3300 &&

arch/mips/bmips/setup.c

@@ -34,6 +34,9 @@
 #define REG_BCM6328_OTP		((void __iomem *)CKSEG1ADDR(0x1000062c))
 #define BCM6328_TP1_DISABLED	BIT(9)
 
+/* CBR addr doesn't change and we can cache it */
+void __iomem *bmips_cbr_addr __read_mostly;
+
 extern bool bmips_rac_flush_disable;
 
 static const unsigned long kbase = VMLINUX_LOAD_ADDRESS & 0xfff00000;
@@ -111,7 +114,7 @@ static void bcm6358_quirks(void)
 	 * because the bootloader is not initializing it properly.
 	 */
 	bmips_rac_flush_disable = !!(read_c0_brcm_cmt_local() & (1 << 31)) ||
-				  !!BMIPS_GET_CBR();
+				  !!bmips_cbr_addr;
 }
 
 static void bcm6368_quirks(void)
@@ -144,6 +147,8 @@ static void __init bmips_init_cfe(void)
 
 void __init prom_init(void)
 {
+	/* Cache CBR addr before CPU/DMA setup */
+	bmips_cbr_addr = BMIPS_GET_CBR();
 	bmips_init_cfe();
 	bmips_cpu_setup();
 	register_bmips_smp_ops();

arch/mips/include/asm/bmips.h

@@ -81,6 +81,7 @@ extern char bmips_smp_movevec[];
 extern char bmips_smp_int_vec[];
 extern char bmips_smp_int_vec_end[];
 
+extern void __iomem *bmips_cbr_addr;
 extern int bmips_smp_enabled;
 extern int bmips_cpu_offset;
 extern cpumask_t bmips_booted_mask;

arch/mips/kernel/smp-bmips.c

@@ -518,7 +518,7 @@ static void bmips_set_reset_vec(int cpu, u32 val)
 		info.val = val;
 		bmips_set_reset_vec_remote(&info);
 	} else {
-		void __iomem *cbr = BMIPS_GET_CBR();
+		void __iomem *cbr = bmips_cbr_addr;
 
 		if (cpu == 0)
 			__raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
@@ -591,7 +591,7 @@ asmlinkage void __weak plat_wired_tlb_setup(void)
 
 void bmips_cpu_setup(void)
 {
-	void __iomem __maybe_unused *cbr = BMIPS_GET_CBR();
+	void __iomem __maybe_unused *cbr = bmips_cbr_addr;
 	u32 __maybe_unused cfg;
 
 	switch (current_cpu_type()) {