wan: ixp4xx_hss: prepare compile testing

The ixp4xx_hss driver needs the platform data definition and the
system clock rate to be compiled. Move both into a new platform_data
header file.

This is a prerequisite for compile testing, but turning on compile
testing requires further patches to isolate the SoC headers.

Signed-off-by: Arnd Bergmann <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>
Signed-off-by: Jakub Kicinski <[e-mail]>

arch/arm/mach-ixp4xx/goramo_mlr.c

···
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
+#include <linux/platform_data/wan_ixp4xx_hss.h>
 #include <linux/serial_8250.h>
 #include <asm/mach-types.h>
 #include <asm/mach/arch.h>
···
 		device_tab[devices++] = &device_hss_tab[0]; /* max index 4 */
 	if (hw_bits & CFG_HW_HAS_HSS1)
 		device_tab[devices++] = &device_hss_tab[1]; /* max index 5 */
+
+	hss_plat[0].timer_freq = ixp4xx_timer_freq;
+	hss_plat[1].timer_freq = ixp4xx_timer_freq;
 
 	gpio_request(GPIO_SCL, "SCL/clock");
 	gpio_request(GPIO_SDA, "SDA/data");

arch/arm/mach-ixp4xx/include/mach/platform.h

···
 	u8 hwaddr[6];
 };
 
-/* Information about built-in HSS (synchronous serial) interfaces */
-struct hss_plat_info {
-	int (*set_clock)(int port, unsigned int clock_type);
-	int (*open)(int port, void *pdev,
-		    void (*set_carrier_cb)(void *pdev, int carrier));
-	void (*close)(int port, void *pdev);
-	u8 txreadyq;
-};
-
 /*
  * Frequency of clock used for primary clocksource
  */

drivers/net/wan/Kconfig

···
 
 config IXP4XX_HSS
 	tristate "Intel IXP4xx HSS (synchronous serial port) support"
-	depends on HDLC && ARM && ARCH_IXP4XX && IXP4XX_NPE && IXP4XX_QMGR
+	depends on HDLC && IXP4XX_NPE && IXP4XX_QMGR
+	depends on ARCH_IXP4XX
 	help
 	  Say Y here if you want to use built-in HSS ports
 	  on IXP4xx processor.

drivers/net/wan/ixp4xx_hss.c

···
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
+#include <linux/platform_data/wan_ixp4xx_hss.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
 #include <linux/soc/ixp4xx/npe.h>
···
 	}
 }
 
-static u32 check_clock(u32 rate, u32 a, u32 b, u32 c,
+static u32 check_clock(u32 timer_freq, u32 rate, u32 a, u32 b, u32 c,
 		       u32 *best, u32 *best_diff, u32 *reg)
 {
 	/* a is 10-bit, b is 10-bit, c is 12-bit */
 	u64 new_rate;
 	u32 new_diff;
 
-	new_rate = ixp4xx_timer_freq * (u64)(c + 1);
+	new_rate = timer_freq * (u64)(c + 1);
 	do_div(new_rate, a * (c + 1) + b + 1);
 	new_diff = abs((u32)new_rate - rate);
 
···
 	return new_diff;
 }
 
-static void find_best_clock(u32 rate, u32 *best, u32 *reg)
+static void find_best_clock(u32 timer_freq, u32 rate, u32 *best, u32 *reg)
 {
 	u32 a, b, diff = 0xFFFFFFFF;
 
-	a = ixp4xx_timer_freq / rate;
+	a = timer_freq / rate;
 
 	if (a > 0x3FF) { /* 10-bit value - we can go as slow as ca. 65 kb/s */
-		check_clock(rate, 0x3FF, 1, 1, best, &diff, reg);
+		check_clock(timer_freq, rate, 0x3FF, 1, 1, best, &diff, reg);
 		return;
 	}
 	if (a == 0) { /* > 66.666 MHz */
 		a = 1; /* minimum divider is 1 (a = 0, b = 1, c = 1) */
-		rate = ixp4xx_timer_freq;
+		rate = timer_freq;
 	}
 
-	if (rate * a == ixp4xx_timer_freq) { /* don't divide by 0 later */
-		check_clock(rate, a - 1, 1, 1, best, &diff, reg);
+	if (rate * a == timer_freq) { /* don't divide by 0 later */
+		check_clock(timer_freq, rate, a - 1, 1, 1, best, &diff, reg);
 		return;
 	}
 
 	for (b = 0; b < 0x400; b++) {
 		u64 c = (b + 1) * (u64)rate;
-		do_div(c, ixp4xx_timer_freq - rate * a);
+		do_div(c, timer_freq - rate * a);
 		c--;
 		if (c >= 0xFFF) { /* 12-bit - no need to check more 'b's */
 			if (b == 0 && /* also try a bit higher rate */
-			    !check_clock(rate, a - 1, 1, 1, best, &diff, reg))
+			    !check_clock(timer_freq, rate, a - 1, 1, 1, best,
+					 &diff, reg))
 				return;
-			check_clock(rate, a, b, 0xFFF, best, &diff, reg);
+			check_clock(timer_freq, rate, a, b, 0xFFF, best,
+				    &diff, reg);
 			return;
 		}
-		if (!check_clock(rate, a, b, c, best, &diff, reg))
+		if (!check_clock(timer_freq, rate, a, b, c, best, &diff, reg))
 			return;
-		if (!check_clock(rate, a, b, c + 1, best, &diff, reg))
+		if (!check_clock(timer_freq, rate, a, b, c + 1, best, &diff,
+				 reg))
 			return;
 	}
 }
···
 
 		port->clock_type = clk; /* Update settings */
 		if (clk == CLOCK_INT)
-			find_best_clock(new_line.clock_rate, &port->clock_rate,
-					&port->clock_reg);
+			find_best_clock(port->plat->timer_freq,
+					new_line.clock_rate,
+					&port->clock_rate, &port->clock_reg);
 		else {
 			port->clock_rate = 0;
 			port->clock_reg = CLK42X_SPEED_2048KHZ;

include/linux/platform_data/wan_ixp4xx_hss.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PLATFORM_DATA_WAN_IXP4XX_HSS_H
+#define __PLATFORM_DATA_WAN_IXP4XX_HSS_H
+
+#include <linux/types.h>
+
+/* Information about built-in HSS (synchronous serial) interfaces */
+struct hss_plat_info {
+	int (*set_clock)(int port, unsigned int clock_type);
+	int (*open)(int port, void *pdev,
+		    void (*set_carrier_cb)(void *pdev, int carrier));
+	void (*close)(int port, void *pdev);
+	u8 txreadyq;
+	u32 timer_freq;
+};
+
+#endif