ARC fixes for 4.14-rc7

- Fixes for HSDK platform
  - module build error for !LLSC config
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Merge tag 'arc-4.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC fixes from Vineet Gupta:

 - Fixes for HSDK platform

 - module build error for !LLSC config

* tag 'arc-4.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: unbork module link errors with !CONFIG_ARC_HAS_LLSC
  ARC: [plat-hsdk] Increase SDIO CIU frequency to 50000000Hz
  ARC: [plat-hsdk] select CONFIG_RESET_HSDK from Kconfig

arch/arc/boot/dts/hsdk.dts

@@ -137,14 +137,15 @@
 			/*
 			 * DW sdio controller has external ciu clock divider
 			 * controlled via register in SDIO IP. Due to its
-			 * unexpected default value (it should devide by 1
-			 * but it devides by 8) SDIO IP uses wrong clock and
+			 * unexpected default value (it should divide by 1
+			 * but it divides by 8) SDIO IP uses wrong clock and
 			 * works unstable (see STAR 9001204800)
+			 * We switched to the minimum possible value of the
+			 * divisor (div-by-2) in HSDK platform code.
 			 * So add temporary fix and change clock frequency
-			 * from 100000000 to 12500000 Hz until we fix dw sdio
-			 * driver itself.
+			 * to 50000000 Hz until we fix dw sdio driver itself.
 			 */
-			clock-frequency = <12500000>;
+			clock-frequency = <50000000>;
 			#clock-cells = <0>;
 		};
 

arch/arc/configs/hsdk_defconfig

@@ -63,7 +63,6 @@ CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_PLTFM=y
 CONFIG_MMC_DW=y
 # CONFIG_IOMMU_SUPPORT is not set
-CONFIG_RESET_HSDK=y
 CONFIG_EXT3_FS=y
 CONFIG_VFAT_FS=y
 CONFIG_TMPFS=y

arch/arc/kernel/smp.c

@@ -23,6 +23,8 @@
 #include <linux/cpumask.h>
 #include <linux/reboot.h>
 #include <linux/irqdomain.h>
+#include <linux/export.h>
+
 #include <asm/processor.h>
 #include <asm/setup.h>
 #include <asm/mach_desc.h>
@@ -30,6 +32,9 @@
 #ifndef CONFIG_ARC_HAS_LLSC
 arch_spinlock_t smp_atomic_ops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 arch_spinlock_t smp_bitops_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+
+EXPORT_SYMBOL_GPL(smp_atomic_ops_lock);
+EXPORT_SYMBOL_GPL(smp_bitops_lock);
 #endif
 
 struct plat_smp_ops  __weak plat_smp_ops;

arch/arc/plat-hsdk/Kconfig

@@ -8,3 +8,4 @@
 menuconfig ARC_SOC_HSDK
 	bool "ARC HS Development Kit SOC"
 	select CLK_HSDK
+	select RESET_HSDK

arch/arc/plat-hsdk/platform.c

@@ -74,6 +74,10 @@ static void __init hsdk_set_cpu_freq_1ghz(void)
 		pr_err("Failed to setup CPU frequency to 1GHz!");
 }
 
+#define SDIO_BASE		(ARC_PERIPHERAL_BASE + 0xA000)
+#define SDIO_UHS_REG_EXT	(SDIO_BASE + 0x108)
+#define SDIO_UHS_REG_EXT_DIV_2	(2 << 30)
+
 static void __init hsdk_init_early(void)
 {
 	/*
@@ -89,6 +93,12 @@ static void __init hsdk_init_early(void)
 	/* Really apply settings made above */
 	writel(1, (void __iomem *) CREG_PAE_UPDATE);
 
+	/*
+	 * Switch SDIO external ciu clock divider from default div-by-8 to
+	 * minimum possible div-by-2.
+	 */
+	iowrite32(SDIO_UHS_REG_EXT_DIV_2, (void __iomem *) SDIO_UHS_REG_EXT);
+
 	/*
 	 * Setup CPU frequency to 1GHz.
 	 * TODO: remove it after smart hsdk pll driver will be introduced.