fix(plat/marvell/a3720/uart): fix UART parent clock rate determination

The UART code for the A3K platform assumes that UART parent clock rate
is always 25 MHz. This is incorrect, because the xtal clock can also run
at 40 MHz (this is board specific).

The frequency of the xtal clock is determined by a value on a strapping
pin during SOC reset. The code to determine this frequency is already in
A3K's comphy driver.

Move the get_ref_clk() function from the comphy driver to a separate
file and use it for UART parent clock rate determination.
Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I8bb18a2d020ef18fe65aa06ffa4ab205c71be92e

drivers/marvell/comphy/phy-comphy-3700.c

@@ -14,6 +14,7 @@
 
 #include <mvebu.h>
 #include <mvebu_def.h>
+#include <plat_marvell.h>
 
 #include "phy-comphy-3700.h"
 #include "phy-comphy-common.h"
@@ -29,15 +30,6 @@
 #define USB3_GBE1_PHY		(MVEBU_REGS_BASE + 0x5C000)
 #define COMPHY_SD_ADDR		(MVEBU_REGS_BASE + 0x1F000)
 
-/*
- * Below address in used only for reading, therefore no problem with concurrent
- * Linux access.
- */
-#define MVEBU_TEST_PIN_LATCH_N (MVEBU_NB_GPIO_REG_BASE + 0x8)
- #define MVEBU_XTAL_MODE_MASK		BIT(9)
- #define MVEBU_XTAL_MODE_OFFS		9
- #define MVEBU_XTAL_CLOCK_25MHZ		0x0
-
 struct sgmii_phy_init_data_fix {
 	uint16_t addr;
 	uint16_t value;
@@ -125,20 +117,6 @@ static uint16_t sgmii_phy_init[512] = {
 	0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000	/*1F8 */
 };
 
-/* returns reference clock in MHz (25 or 40) */
-static uint32_t get_ref_clk(void)
-{
-	uint32_t val;
-
-	val = (mmio_read_32(MVEBU_TEST_PIN_LATCH_N) & MVEBU_XTAL_MODE_MASK) >>
-		MVEBU_XTAL_MODE_OFFS;
-
-	if (val == MVEBU_XTAL_CLOCK_25MHZ)
-		return 25;
-	else
-		return 40;
-}
-
 /* PHY selector configures with corresponding modes */
 static void mvebu_a3700_comphy_set_phy_selector(uint8_t comphy_index,
 						uint32_t comphy_mode)

include/plat/marvell/armada/a3k/common/plat_marvell.h

@@ -100,4 +100,6 @@ void plat_marvell_interconnect_enter_coherency(void);
 
 const mmap_region_t *plat_marvell_get_mmap(void);
 
+uint32_t get_ref_clk(void);
+
 #endif /* PLAT_MARVELL_H */

plat/marvell/armada/a3k/common/a3700_common.mk

@@ -38,6 +38,7 @@ PLAT_INCLUDES		:=	-I$(PLAT_FAMILY_BASE)/$(PLAT)		\
 				-I$/drivers/arm/gic/common/
 
 PLAT_BL_COMMON_SOURCES	:=	$(PLAT_COMMON_BASE)/aarch64/a3700_common.c \
+				$(PLAT_COMMON_BASE)/aarch64/a3700_clock.S \
 				$(MARVELL_DRV_BASE)/uart/a3700_console.S
 
 BL1_SOURCES		+=	$(PLAT_COMMON_BASE)/aarch64/plat_helpers.S \

plat/marvell/armada/a3k/common/aarch64/a3700_clock.S

+/*
+ * Copyright (C) 2018 Marvell International Ltd.
+ *
+ * SPDX-License-Identifier:	BSD-3-Clause
+ * https://spdx.org/licenses
+ */
+
+#include <asm_macros.S>
+#include <platform_def.h>
+
+/*
+ * Below address in used only for reading, therefore no problem with concurrent
+ * Linux access.
+ */
+#define MVEBU_TEST_PIN_LATCH_N (MVEBU_NB_GPIO_REG_BASE + 0x8)
+ #define MVEBU_XTAL_MODE_MASK		BIT(9)
+
+	/* -----------------------------------------------------
+	 * uint32_t get_ref_clk (void);
+	 *
+	 * returns reference clock in MHz (25 or 40)
+	 * -----------------------------------------------------
+	 */
+.globl	get_ref_clk
+func get_ref_clk
+	mov_imm	x0, MVEBU_TEST_PIN_LATCH_N
+	ldr	w0, [x0]
+	tst	w0, #MVEBU_XTAL_MODE_MASK
+	bne	40
+	mov	w0, #25
+	ret
+40:
+	mov	w0, #40
+	ret
+endfunc get_ref_clk

plat/marvell/armada/a3k/common/include/platform_def.h

@@ -164,7 +164,6 @@
  * PL011 related constants
  */
 #define PLAT_MARVELL_UART_BASE			(MVEBU_REGS_BASE + 0x12000)
-#define PLAT_MARVELL_UART_CLK_IN_HZ		25000000
 
 /* Required platform porting definitions */
 #define PLAT_MAX_PWR_LVL			MPIDR_AFFLVL1

plat/marvell/armada/common/aarch64/marvell_helpers.S

@@ -63,8 +63,16 @@ endfunc plat_marvell_calc_core_pos
 	 * ---------------------------------------------
 	 */
 func plat_crash_console_init
-	mov_imm	x0, PLAT_MARVELL_UART_BASE
+#ifdef PLAT_a3700
+	mov	x1, x30
+	bl	get_ref_clk
+	mov	x30, x1
+	mov_imm	x1, 1000000
+	mul	x1, x0, x1
+#else
 	mov_imm	x1, PLAT_MARVELL_UART_CLK_IN_HZ
+#endif
+	mov_imm	x0, PLAT_MARVELL_UART_BASE
 	mov_imm	x2, MARVELL_CONSOLE_BAUDRATE
 #ifdef PLAT_a3700
 	b	console_a3700_core_init

plat/marvell/armada/common/marvell_console.c

@@ -14,6 +14,7 @@
 
 #ifdef PLAT_a3700
 #include <drivers/marvell/uart/a3700_console.h>
+#define PLAT_MARVELL_UART_CLK_IN_HZ (get_ref_clk() * 1000000)
 #define console_marvell_register console_a3700_register
 #else
 #include <drivers/ti/uart/uart_16550.h>