ARM: mvebu: remove Armada 375 Z1 workaround for I/O coherency

This reverts commit 5ab5afd8ba83 ("ARM: mvebu: implement Armada 375
coherency workaround"), since we are removing the support for the very
early Z1 revision of the Armada 375 SoC.

This commit is an exact revert, with two exceptions:

 - minor adaptations needed due to other changes that have taken place
   in coherency.c since the original commit

 - keep the definition of pr_fmt. This shouldn't originally have been
   part of the Armada 375 Z1 workaround commit since it had nothing to
   do with it.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Link: https://lkml.kernel.org/r/1415871540-20302-5-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

arch/arm/mach-mvebu/coherency.c

@@ -28,7 +28,6 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/mbus.h>
-#include <linux/clk.h>
 #include <linux/pci.h>
 #include <asm/smp_plat.h>
 #include <asm/cacheflush.h>
@@ -77,157 +76,8 @@ int set_cpu_coherent(void)
 	return ll_enable_coherency();
 }
 
-/*
- * The below code implements the I/O coherency workaround on Armada
- * 375. This workaround consists in using the two channels of the
- * first XOR engine to trigger a XOR transaction that serves as the
- * I/O coherency barrier.
- */
-
-static void __iomem *xor_base, *xor_high_base;
-static dma_addr_t coherency_wa_buf_phys[CONFIG_NR_CPUS];
-static void *coherency_wa_buf[CONFIG_NR_CPUS];
-static bool coherency_wa_enabled;
-
-#define XOR_CONFIG(chan)            (0x10 + (chan * 4))
-#define XOR_ACTIVATION(chan)        (0x20 + (chan * 4))
-#define WINDOW_BAR_ENABLE(chan)     (0x240 + ((chan) << 2))
-#define WINDOW_BASE(w)              (0x250 + ((w) << 2))
-#define WINDOW_SIZE(w)              (0x270 + ((w) << 2))
-#define WINDOW_REMAP_HIGH(w)        (0x290 + ((w) << 2))
-#define WINDOW_OVERRIDE_CTRL(chan)  (0x2A0 + ((chan) << 2))
-#define XOR_DEST_POINTER(chan)      (0x2B0 + (chan * 4))
-#define XOR_BLOCK_SIZE(chan)        (0x2C0 + (chan * 4))
-#define XOR_INIT_VALUE_LOW           0x2E0
-#define XOR_INIT_VALUE_HIGH          0x2E4
-
-static inline void mvebu_hwcc_armada375_sync_io_barrier_wa(void)
-{
-	int idx = smp_processor_id();
-
-	/* Write '1' to the first word of the buffer */
-	writel(0x1, coherency_wa_buf[idx]);
-
-	/* Wait until the engine is idle */
-	while ((readl(xor_base + XOR_ACTIVATION(idx)) >> 4) & 0x3)
-		;
-
-	dmb();
-
-	/* Trigger channel */
-	writel(0x1, xor_base + XOR_ACTIVATION(idx));
-
-	/* Poll the data until it is cleared by the XOR transaction */
-	while (readl(coherency_wa_buf[idx]))
-		;
-}
-
-static void __init armada_375_coherency_init_wa(void)
-{
-	const struct mbus_dram_target_info *dram;
-	struct device_node *xor_node;
-	struct property *xor_status;
-	struct clk *xor_clk;
-	u32 win_enable = 0;
-	int i;
-
-	pr_warn("enabling coherency workaround for Armada 375 Z1, one XOR engine disabled\n");
-
-	/*
-	 * Since the workaround uses one XOR engine, we grab a
-	 * reference to its Device Tree node first.
-	 */
-	xor_node = of_find_compatible_node(NULL, NULL, "marvell,orion-xor");
-	BUG_ON(!xor_node);
-
-	/*
-	 * Then we mark it as disabled so that the real XOR driver
-	 * will not use it.
-	 */
-	xor_status = kzalloc(sizeof(struct property), GFP_KERNEL);
-	BUG_ON(!xor_status);
-
-	xor_status->value = kstrdup("disabled", GFP_KERNEL);
-	BUG_ON(!xor_status->value);
-
-	xor_status->length = 8;
-	xor_status->name = kstrdup("status", GFP_KERNEL);
-	BUG_ON(!xor_status->name);
-
-	of_update_property(xor_node, xor_status);
-
-	/*
-	 * And we remap the registers, get the clock, and do the
-	 * initial configuration of the XOR engine.
-	 */
-	xor_base = of_iomap(xor_node, 0);
-	xor_high_base = of_iomap(xor_node, 1);
-
-	xor_clk = of_clk_get_by_name(xor_node, NULL);
-	BUG_ON(!xor_clk);
-
-	clk_prepare_enable(xor_clk);
-
-	dram = mv_mbus_dram_info();
-
-	for (i = 0; i < 8; i++) {
-		writel(0, xor_base + WINDOW_BASE(i));
-		writel(0, xor_base + WINDOW_SIZE(i));
-		if (i < 4)
-			writel(0, xor_base + WINDOW_REMAP_HIGH(i));
-	}
-
-	for (i = 0; i < dram->num_cs; i++) {
-		const struct mbus_dram_window *cs = dram->cs + i;
-		writel((cs->base & 0xffff0000) |
-		       (cs->mbus_attr << 8) |
-		       dram->mbus_dram_target_id, xor_base + WINDOW_BASE(i));
-		writel((cs->size - 1) & 0xffff0000, xor_base + WINDOW_SIZE(i));
-
-		win_enable |= (1 << i);
-		win_enable |= 3 << (16 + (2 * i));
-	}
-
-	writel(win_enable, xor_base + WINDOW_BAR_ENABLE(0));
-	writel(win_enable, xor_base + WINDOW_BAR_ENABLE(1));
-	writel(0, xor_base + WINDOW_OVERRIDE_CTRL(0));
-	writel(0, xor_base + WINDOW_OVERRIDE_CTRL(1));
-
-	for (i = 0; i < CONFIG_NR_CPUS; i++) {
-		coherency_wa_buf[i] = kzalloc(PAGE_SIZE, GFP_KERNEL);
-		BUG_ON(!coherency_wa_buf[i]);
-
-		/*
-		 * We can't use the DMA mapping API, since we don't
-		 * have a valid 'struct device' pointer
-		 */
-		coherency_wa_buf_phys[i] =
-			virt_to_phys(coherency_wa_buf[i]);
-		BUG_ON(!coherency_wa_buf_phys[i]);
-
-		/*
-		 * Configure the XOR engine for memset operation, with
-		 * a 128 bytes block size
-		 */
-		writel(0x444, xor_base + XOR_CONFIG(i));
-		writel(128, xor_base + XOR_BLOCK_SIZE(i));
-		writel(coherency_wa_buf_phys[i],
-		       xor_base + XOR_DEST_POINTER(i));
-	}
-
-	writel(0x0, xor_base + XOR_INIT_VALUE_LOW);
-	writel(0x0, xor_base + XOR_INIT_VALUE_HIGH);
-
-	coherency_wa_enabled = true;
-}
-
 static inline void mvebu_hwcc_sync_io_barrier(void)
 {
-	if (coherency_wa_enabled) {
-		mvebu_hwcc_armada375_sync_io_barrier_wa();
-		return;
-	}
-
 	writel(0x1, coherency_cpu_base + IO_SYNC_BARRIER_CTL_OFFSET);
 	while (readl(coherency_cpu_base + IO_SYNC_BARRIER_CTL_OFFSET) & 0x1);
 }
@@ -421,22 +271,9 @@ int __init coherency_init(void)
 
 static int __init coherency_late_init(void)
 {
-	int type = coherency_type();
-
-	if (type == COHERENCY_FABRIC_TYPE_NONE)
-		return 0;
-
-	if (type == COHERENCY_FABRIC_TYPE_ARMADA_375) {
-		u32 dev, rev;
-
-		if (mvebu_get_soc_id(&dev, &rev) == 0 &&
-		    rev == ARMADA_375_Z1_REV)
-			armada_375_coherency_init_wa();
-	}
-
-	bus_register_notifier(&platform_bus_type,
-			      &mvebu_hwcc_nb);
-
+	if (coherency_available())
+		bus_register_notifier(&platform_bus_type,
+				      &mvebu_hwcc_nb);
 	return 0;
 }