MIPS: ath25: add board configuration detection

All boards based on AR5312/AR2315 SoC have a special structure located
at the end of flash. This structure contains board-specific data such as
Ethernet and Wireless MAC addresses. The flash is mapped to the memmory
at predefined location.

Signed-off-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Linux MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/8243/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

8 files changed, 300 insertions, 0 deletions

diff --git a/arch/mips/ath25/ar2315.c b/arch/mips/ath25/ar2315.c
index d10eac4cd828..3ba8e757add6 100644
--- a/arch/mips/ath25/ar2315.c
+++ b/arch/mips/ath25/ar2315.c
@@ -160,6 +160,12 @@ void __init ar2315_arch_init_irq(void)
         ar2315_misc_irq_domain = domain;
 }
 
+void __init ar2315_init_devices(void)
+{
+        /* Find board configuration */
+        ath25_find_config(AR2315_SPI_READ_BASE, AR2315_SPI_READ_SIZE);
+}
+
 static void ar2315_restart(char *command)
 {
         void (*mips_reset_vec)(void) = (void *)0xbfc00000;
diff --git a/arch/mips/ath25/ar2315.h b/arch/mips/ath25/ar2315.h
index 4af5f4c75f44..877afe63eed5 100644
--- a/arch/mips/ath25/ar2315.h
+++ b/arch/mips/ath25/ar2315.h
@@ -4,6 +4,7 @@
 #ifdef CONFIG_SOC_AR2315
 
 void ar2315_arch_init_irq(void);
+void ar2315_init_devices(void);
 void ar2315_plat_time_init(void);
 void ar2315_plat_mem_setup(void);
 void ar2315_arch_init(void);
@@ -11,6 +12,7 @@ void ar2315_arch_init(void);
 #else
 
 static inline void ar2315_arch_init_irq(void) {}
+static inline void ar2315_init_devices(void) {}
 static inline void ar2315_plat_time_init(void) {}
 static inline void ar2315_plat_mem_setup(void) {}
 static inline void ar2315_arch_init(void) {}
diff --git a/arch/mips/ath25/ar5312.c b/arch/mips/ath25/ar5312.c
index 398d4fd4dd2d..41bd56d6ab23 100644
--- a/arch/mips/ath25/ar5312.c
+++ b/arch/mips/ath25/ar5312.c
@@ -158,6 +158,45 @@ void __init ar5312_arch_init_irq(void)
         ar5312_misc_irq_domain = domain;
 }
 
+static void __init ar5312_flash_init(void)
+{
+        void __iomem *flashctl_base;
+        u32 ctl;
+
+        flashctl_base = ioremap_nocache(AR5312_FLASHCTL_BASE,
+                                        AR5312_FLASHCTL_SIZE);
+
+        /*
+         * Configure flash bank 0.
+         * Assume 8M window size. Flash will be aliased if it's smaller
+         */
+        ctl = __raw_readl(flashctl_base + AR5312_FLASHCTL0);
+        ctl &= AR5312_FLASHCTL_MW;
+        ctl |= AR5312_FLASHCTL_E | AR5312_FLASHCTL_AC_8M | AR5312_FLASHCTL_RBLE;
+        ctl |= 0x01 << AR5312_FLASHCTL_IDCY_S;
+        ctl |= 0x07 << AR5312_FLASHCTL_WST1_S;
+        ctl |= 0x07 << AR5312_FLASHCTL_WST2_S;
+        __raw_writel(ctl, flashctl_base + AR5312_FLASHCTL0);
+
+        /* Disable other flash banks */
+        ctl = __raw_readl(flashctl_base + AR5312_FLASHCTL1);
+        ctl &= ~(AR5312_FLASHCTL_E | AR5312_FLASHCTL_AC);
+        __raw_writel(ctl, flashctl_base + AR5312_FLASHCTL1);
+        ctl = __raw_readl(flashctl_base + AR5312_FLASHCTL2);
+        ctl &= ~(AR5312_FLASHCTL_E | AR5312_FLASHCTL_AC);
+        __raw_writel(ctl, flashctl_base + AR5312_FLASHCTL2);
+
+        iounmap(flashctl_base);
+}
+
+void __init ar5312_init_devices(void)
+{
+        ar5312_flash_init();
+
+        /* Locate board/radio config data */
+        ath25_find_config(AR5312_FLASH_BASE, AR5312_FLASH_SIZE);
+}
+
 static void ar5312_restart(char *command)
 {
         /* reset the system */
diff --git a/arch/mips/ath25/ar5312.h b/arch/mips/ath25/ar5312.h
index 86dfc6d04a6d..470abb0052bd 100644
--- a/arch/mips/ath25/ar5312.h
+++ b/arch/mips/ath25/ar5312.h
@@ -4,6 +4,7 @@
 #ifdef CONFIG_SOC_AR5312
 
 void ar5312_arch_init_irq(void);
+void ar5312_init_devices(void);
 void ar5312_plat_time_init(void);
 void ar5312_plat_mem_setup(void);
 void ar5312_arch_init(void);
@@ -11,6 +12,7 @@ void ar5312_arch_init(void);
 #else
 
 static inline void ar5312_arch_init_irq(void) {}
+static inline void ar5312_init_devices(void) {}
 static inline void ar5312_plat_time_init(void) {}
 static inline void ar5312_plat_mem_setup(void) {}
 static inline void ar5312_arch_init(void) {}
diff --git a/arch/mips/ath25/board.c b/arch/mips/ath25/board.c
index d4675e04a634..b8bb78282d6a 100644
--- a/arch/mips/ath25/board.c
+++ b/arch/mips/ath25/board.c
@@ -16,12 +16,173 @@
 #include <asm/bootinfo.h>
 #include <asm/time.h>
 
+#include <ath25_platform.h>
 #include "devices.h"
 #include "ar5312.h"
 #include "ar2315.h"
 
 void (*ath25_irq_dispatch)(void);
 
+static inline bool check_radio_magic(const void __iomem *addr)
+{
+        addr += 0x7a; /* offset for flash magic */
+        return (__raw_readb(addr) == 0x5a) && (__raw_readb(addr + 1) == 0xa5);
+}
+
+static inline bool check_notempty(const void __iomem *addr)
+{
+        return __raw_readl(addr) != 0xffffffff;
+}
+
+static inline bool check_board_data(const void __iomem *addr, bool broken)
+{
+        /* config magic found */
+        if (__raw_readl(addr) == ATH25_BD_MAGIC)
+                return true;
+
+        if (!broken)
+                return false;
+
+        /* broken board data detected, use radio data to find the
+         * offset, user will fix this */
+
+        if (check_radio_magic(addr + 0x1000))
+                return true;
+        if (check_radio_magic(addr + 0xf8))
+                return true;
+
+        return false;
+}
+
+static const void __iomem * __init find_board_config(const void __iomem *limit,
+                                                     const bool broken)
+{
+        const void __iomem *addr;
+        const void __iomem *begin = limit - 0x1000;
+        const void __iomem *end = limit - 0x30000;
+
+        for (addr = begin; addr >= end; addr -= 0x1000)
+                if (check_board_data(addr, broken))
+                        return addr;
+
+        return NULL;
+}
+
+static const void __iomem * __init find_radio_config(const void __iomem *limit,
+                                                     const void __iomem *bcfg)
+{
+        const void __iomem *rcfg, *begin, *end;
+
+        /*
+         * Now find the start of Radio Configuration data, using heuristics:
+         * Search forward from Board Configuration data by 0x1000 bytes
+         * at a time until we find non-0xffffffff.
+         */
+        begin = bcfg + 0x1000;
+        end = limit;
+        for (rcfg = begin; rcfg < end; rcfg += 0x1000)
+                if (check_notempty(rcfg) && check_radio_magic(rcfg))
+                        return rcfg;
+
+        /* AR2316 relocates radio config to new location */
+        begin = bcfg + 0xf8;
+        end = limit - 0x1000 + 0xf8;
+        for (rcfg = begin; rcfg < end; rcfg += 0x1000)
+                if (check_notempty(rcfg) && check_radio_magic(rcfg))
+                        return rcfg;
+
+        return NULL;
+}
+
+/*
+ * NB: Search region size could be larger than the actual flash size,
+ * but this shouldn't be a problem here, because the flash
+ * will simply be mapped multiple times.
+ */
+int __init ath25_find_config(phys_addr_t base, unsigned long size)
+{
+        const void __iomem *flash_base, *flash_limit;
+        struct ath25_boarddata *config;
+        unsigned int rcfg_size;
+        int broken_boarddata = 0;
+        const void __iomem *bcfg, *rcfg;
+        u8 *board_data;
+        u8 *radio_data;
+        u8 *mac_addr;
+        u32 offset;
+
+        flash_base = ioremap_nocache(base, size);
+        flash_limit = flash_base + size;
+
+        ath25_board.config = NULL;
+        ath25_board.radio = NULL;
+
+        /* Copy the board and radio data to RAM, because accessing the mapped
+         * memory of the flash directly after booting is not safe */
+
+        /* Try to find valid board and radio data */
+        bcfg = find_board_config(flash_limit, false);
+
+        /* If that fails, try to at least find valid radio data */
+        if (!bcfg) {
+                bcfg = find_board_config(flash_limit, true);
+                broken_boarddata = 1;
+        }
+
+        if (!bcfg) {
+                pr_warn("WARNING: No board configuration data found!\n");
+                goto error;
+        }
+
+        board_data = kzalloc(BOARD_CONFIG_BUFSZ, GFP_KERNEL);
+        ath25_board.config = (struct ath25_boarddata *)board_data;
+        memcpy_fromio(board_data, bcfg, 0x100);
+        if (broken_boarddata) {
+                pr_warn("WARNING: broken board data detected\n");
+                config = ath25_board.config;
+                if (is_zero_ether_addr(config->enet0_mac)) {
+                        pr_info("Fixing up empty mac addresses\n");
+                        config->reset_config_gpio = 0xffff;
+                        config->sys_led_gpio = 0xffff;
+                        random_ether_addr(config->wlan0_mac);
+                        config->wlan0_mac[0] &= ~0x06;
+                        random_ether_addr(config->enet0_mac);
+                        random_ether_addr(config->enet1_mac);
+                }
+        }
+
+        /* Radio config starts 0x100 bytes after board config, regardless
+         * of what the physical layout on the flash chip looks like */
+
+        rcfg = find_radio_config(flash_limit, bcfg);
+        if (!rcfg) {
+                pr_warn("WARNING: Could not find Radio Configuration data\n");
+                goto error;
+        }
+
+        radio_data = board_data + 0x100 + ((rcfg - bcfg) & 0xfff);
+        ath25_board.radio = radio_data;
+        offset = radio_data - board_data;
+        pr_info("Radio config found at offset 0x%x (0x%x)\n", rcfg - bcfg,
+                offset);
+        rcfg_size = BOARD_CONFIG_BUFSZ - offset;
+        memcpy_fromio(radio_data, rcfg, rcfg_size);
+
+        mac_addr = &radio_data[0x1d * 2];
+        if (is_broadcast_ether_addr(mac_addr)) {
+                pr_info("Radio MAC is blank; using board-data\n");
+                ether_addr_copy(mac_addr, ath25_board.config->wlan0_mac);
+        }
+
+        iounmap(flash_base);
+
+        return 0;
+
+error:
+        iounmap(flash_base);
+        return -ENODEV;
+}
+
 static void ath25_halt(void)
 {
         local_irq_disable();
diff --git a/arch/mips/ath25/devices.c b/arch/mips/ath25/devices.c
index 400419d8e7d9..d24dbb1ef8ea 100644
--- a/arch/mips/ath25/devices.c
+++ b/arch/mips/ath25/devices.c
@@ -3,10 +3,13 @@
 #include <linux/serial_8250.h>
 #include <asm/bootinfo.h>
 
+#include <ath25_platform.h>
 #include "devices.h"
 #include "ar5312.h"
 #include "ar2315.h"
 
+struct ar231x_board_config ath25_board;
+
 const char *get_system_type(void)
 {
         return "Atheros (unknown)";
@@ -28,6 +31,18 @@ void __init ath25_serial_setup(u32 mapbase, int irq, unsigned int uartclk)
         early_serial_setup(&s);
 }
 
+static int __init ath25_register_devices(void)
+{
+        if (is_ar5312())
+                ar5312_init_devices();
+        else
+                ar2315_init_devices();
+
+        return 0;
+}
+
+device_initcall(ath25_register_devices);
+
 static int __init ath25_arch_init(void)
 {
         if (is_ar5312())
diff --git a/arch/mips/ath25/devices.h b/arch/mips/ath25/devices.h
index 23b53cb71c72..65e86cc46e49 100644
--- a/arch/mips/ath25/devices.h
+++ b/arch/mips/ath25/devices.h
@@ -7,8 +7,10 @@
 
 #define ATH25_IRQ_CPU_CLOCK     (MIPS_CPU_IRQ_BASE + 7) /* C0_CAUSE: 0x8000 */
 
+extern struct ar231x_board_config ath25_board;
 extern void (*ath25_irq_dispatch)(void);
 
+int ath25_find_config(phys_addr_t offset, unsigned long size);
 void ath25_serial_setup(u32 mapbase, int irq, unsigned int uartclk);
 
 static inline bool is_ar2315(void)
diff --git a/arch/mips/include/asm/mach-ath25/ath25_platform.h b/arch/mips/include/asm/mach-ath25/ath25_platform.h
new file mode 100644
index 000000000000..4f4ee4f9e5ec
--- /dev/null
+++ b/arch/mips/include/asm/mach-ath25/ath25_platform.h
@@ -0,0 +1,73 @@
+#ifndef __ASM_MACH_ATH25_PLATFORM_H
+#define __ASM_MACH_ATH25_PLATFORM_H
+
+#include <linux/etherdevice.h>
+
+/*
+ * This is board-specific data that is stored in a "fixed" location in flash.
+ * It is shared across operating systems, so it should not be changed lightly.
+ * The main reason we need it is in order to extract the ethernet MAC
+ * address(es).
+ */
+struct ath25_boarddata {
+        u32 magic;                   /* board data is valid */
+#define ATH25_BD_MAGIC 0x35333131    /* "5311", for all 531x/231x platforms */
+        u16 cksum;                   /* checksum (starting with BD_REV 2) */
+        u16 rev;                     /* revision of this struct */
+#define BD_REV 4
+        char board_name[64];         /* Name of board */
+        u16 major;                   /* Board major number */
+        u16 minor;                   /* Board minor number */
+        u32 flags;                   /* Board configuration */
+#define BD_ENET0        0x00000001   /* ENET0 is stuffed */
+#define BD_ENET1        0x00000002   /* ENET1 is stuffed */
+#define BD_UART1        0x00000004   /* UART1 is stuffed */
+#define BD_UART0        0x00000008   /* UART0 is stuffed (dma) */
+#define BD_RSTFACTORY   0x00000010   /* Reset factory defaults stuffed */
+#define BD_SYSLED       0x00000020   /* System LED stuffed */
+#define BD_EXTUARTCLK   0x00000040   /* External UART clock */
+#define BD_CPUFREQ      0x00000080   /* cpu freq is valid in nvram */
+#define BD_SYSFREQ      0x00000100   /* sys freq is set in nvram */
+#define BD_WLAN0        0x00000200   /* Enable WLAN0 */
+#define BD_MEMCAP       0x00000400   /* CAP SDRAM @ mem_cap for testing */
+#define BD_DISWATCHDOG  0x00000800   /* disable system watchdog */
+#define BD_WLAN1        0x00001000   /* Enable WLAN1 (ar5212) */
+#define BD_ISCASPER     0x00002000   /* FLAG for AR2312 */
+#define BD_WLAN0_2G_EN  0x00004000   /* FLAG for radio0_2G */
+#define BD_WLAN0_5G_EN  0x00008000   /* FLAG for radio0_2G */
+#define BD_WLAN1_2G_EN  0x00020000   /* FLAG for radio0_2G */
+#define BD_WLAN1_5G_EN  0x00040000   /* FLAG for radio0_2G */
+        u16 reset_config_gpio;       /* Reset factory GPIO pin */
+        u16 sys_led_gpio;            /* System LED GPIO pin */
+
+        u32 cpu_freq;                /* CPU core frequency in Hz */
+        u32 sys_freq;                /* System frequency in Hz */
+        u32 cnt_freq;                /* Calculated C0_COUNT frequency */
+
+        u8  wlan0_mac[ETH_ALEN];
+        u8  enet0_mac[ETH_ALEN];
+        u8  enet1_mac[ETH_ALEN];
+
+        u16 pci_id;                  /* Pseudo PCIID for common code */
+        u16 mem_cap;                 /* cap bank1 in MB */
+
+        /* version 3 */
+        u8  wlan1_mac[ETH_ALEN];     /* (ar5212) */
+};
+
+#define BOARD_CONFIG_BUFSZ              0x1000
+
+/*
+ * Platform device information for the Wireless MAC
+ */
+struct ar231x_board_config {
+        u16 devid;
+
+        /* board config data */
+        struct ath25_boarddata *config;
+
+        /* radio calibration data */
+        const char *radio;
+};
+
+#endif /* __ASM_MACH_ATH25_PLATFORM_H */