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-rw-r--r--arch/tile/lib/cacheflush.c167
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diff --git a/arch/tile/lib/cacheflush.c b/arch/tile/lib/cacheflush.c
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+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT. See the GNU General Public License for
+ * more details.
+ */
+
+#include <asm/page.h>
+#include <asm/cacheflush.h>
+#include <arch/icache.h>
+#include <arch/spr_def.h>
+
+
+void __flush_icache_range(unsigned long start, unsigned long end)
+{
+ invalidate_icache((const void *)start, end - start, PAGE_SIZE);
+}
+
+
+/* Force a load instruction to issue. */
+static inline void force_load(char *p)
+{
+ *(volatile char *)p;
+}
+
+/*
+ * Flush and invalidate a VA range that is homed remotely on a single
+ * core (if "!hfh") or homed via hash-for-home (if "hfh"), waiting
+ * until the memory controller holds the flushed values.
+ */
+void finv_buffer_remote(void *buffer, size_t size, int hfh)
+{
+ char *p, *base;
+ size_t step_size, load_count;
+
+ /*
+ * On TILEPro the striping granularity is a fixed 8KB; on
+ * TILE-Gx it is configurable, and we rely on the fact that
+ * the hypervisor always configures maximum striping, so that
+ * bits 9 and 10 of the PA are part of the stripe function, so
+ * every 512 bytes we hit a striping boundary.
+ *
+ */
+#ifdef __tilegx__
+ const unsigned long STRIPE_WIDTH = 512;
+#else
+ const unsigned long STRIPE_WIDTH = 8192;
+#endif
+
+#ifdef __tilegx__
+ /*
+ * On TILE-Gx, we must disable the dstream prefetcher before doing
+ * a cache flush; otherwise, we could end up with data in the cache
+ * that we don't want there. Note that normally we'd do an mf
+ * after the SPR write to disabling the prefetcher, but we do one
+ * below, before any further loads, so there's no need to do it
+ * here.
+ */
+ uint_reg_t old_dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);
+ __insn_mtspr(SPR_DSTREAM_PF, 0);
+#endif
+
+ /*
+ * Flush and invalidate the buffer out of the local L1/L2
+ * and request the home cache to flush and invalidate as well.
+ */
+ __finv_buffer(buffer, size);
+
+ /*
+ * Wait for the home cache to acknowledge that it has processed
+ * all the flush-and-invalidate requests. This does not mean
+ * that the flushed data has reached the memory controller yet,
+ * but it does mean the home cache is processing the flushes.
+ */
+ __insn_mf();
+
+ /*
+ * Issue a load to the last cache line, which can't complete
+ * until all the previously-issued flushes to the same memory
+ * controller have also completed. If we weren't striping
+ * memory, that one load would be sufficient, but since we may
+ * be, we also need to back up to the last load issued to
+ * another memory controller, which would be the point where
+ * we crossed a "striping" boundary (the granularity of striping
+ * across memory controllers). Keep backing up and doing this
+ * until we are before the beginning of the buffer, or have
+ * hit all the controllers.
+ *
+ * If we are flushing a hash-for-home buffer, it's even worse.
+ * Each line may be homed on a different tile, and each tile
+ * may have up to four lines that are on different
+ * controllers. So as we walk backwards, we have to touch
+ * enough cache lines to satisfy these constraints. In
+ * practice this ends up being close enough to "load from
+ * every cache line on a full memory stripe on each
+ * controller" that we simply do that, to simplify the logic.
+ *
+ * On TILE-Gx the hash-for-home function is much more complex,
+ * with the upshot being we can't readily guarantee we have
+ * hit both entries in the 128-entry AMT that were hit by any
+ * load in the entire range, so we just re-load them all.
+ * With larger buffers, we may want to consider using a hypervisor
+ * trap to issue loads directly to each hash-for-home tile for
+ * each controller (doing it from Linux would trash the TLB).
+ */
+ if (hfh) {
+ step_size = L2_CACHE_BYTES;
+#ifdef __tilegx__
+ load_count = (size + L2_CACHE_BYTES - 1) / L2_CACHE_BYTES;
+#else
+ load_count = (STRIPE_WIDTH / L2_CACHE_BYTES) *
+ (1 << CHIP_LOG_NUM_MSHIMS());
+#endif
+ } else {
+ step_size = STRIPE_WIDTH;
+ load_count = (1 << CHIP_LOG_NUM_MSHIMS());
+ }
+
+ /* Load the last byte of the buffer. */
+ p = (char *)buffer + size - 1;
+ force_load(p);
+
+ /* Bump down to the end of the previous stripe or cache line. */
+ p -= step_size;
+ p = (char *)((unsigned long)p | (step_size - 1));
+
+ /* Figure out how far back we need to go. */
+ base = p - (step_size * (load_count - 2));
+ if ((unsigned long)base < (unsigned long)buffer)
+ base = buffer;
+
+ /*
+ * Fire all the loads we need. The MAF only has eight entries
+ * so we can have at most eight outstanding loads, so we
+ * unroll by that amount.
+ */
+#pragma unroll 8
+ for (; p >= base; p -= step_size)
+ force_load(p);
+
+ /*
+ * Repeat, but with inv's instead of loads, to get rid of the
+ * data we just loaded into our own cache and the old home L3.
+ * No need to unroll since inv's don't target a register.
+ */
+ p = (char *)buffer + size - 1;
+ __insn_inv(p);
+ p -= step_size;
+ p = (char *)((unsigned long)p | (step_size - 1));
+ for (; p >= base; p -= step_size)
+ __insn_inv(p);
+
+ /* Wait for the load+inv's (and thus finvs) to have completed. */
+ __insn_mf();
+
+#ifdef __tilegx__
+ /* Reenable the prefetcher. */
+ __insn_mtspr(SPR_DSTREAM_PF, old_dstream_pf);
+#endif
+}