1 files changed, 404 insertions, 0 deletions
diff --git a/arch/cris/arch-v32/mach-fs/arbiter.c b/arch/cris/arch-v32/mach-fs/arbiter.c
new file mode 100644
index 000000000..c97f4d812
--- /dev/null
+++ b/arch/cris/arch-v32/mach-fs/arbiter.c
@@ -0,0 +1,404 @@
+/*
+ * Memory arbiter functions. Allocates bandwidth through the
+ * arbiter and sets up arbiter breakpoints.
+ *
+ * The algorithm first assigns slots to the clients that has specified
+ * bandwidth (e.g. ethernet) and then the remaining slots are divided
+ * on all the active clients.
+ *
+ * Copyright (c) 2004-2007 Axis Communications AB.
+ */
+
+#include <hwregs/reg_map.h>
+#include <hwregs/reg_rdwr.h>
+#include <hwregs/marb_defs.h>
+#include <arbiter.h>
+#include <hwregs/intr_vect.h>
+#include <linux/interrupt.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/spinlock.h>
+#include <asm/io.h>
+#include <asm/irq_regs.h>
+
+struct crisv32_watch_entry {
+	unsigned long instance;
+	watch_callback *cb;
+	unsigned long start;
+	unsigned long end;
+	int used;
+};
+
+#define NUMBER_OF_BP 4
+#define NBR_OF_CLIENTS 14
+#define NBR_OF_SLOTS 64
+#define SDRAM_BANDWIDTH 100000000	/* Some kind of expected value */
+#define INTMEM_BANDWIDTH 400000000
+#define NBR_OF_REGIONS 2
+
+static struct crisv32_watch_entry watches[NUMBER_OF_BP] = {
+	{regi_marb_bp0},
+	{regi_marb_bp1},
+	{regi_marb_bp2},
+	{regi_marb_bp3}
+};
+
+static u8 requested_slots[NBR_OF_REGIONS][NBR_OF_CLIENTS];
+static u8 active_clients[NBR_OF_REGIONS][NBR_OF_CLIENTS];
+static int max_bandwidth[NBR_OF_REGIONS] =
+    { SDRAM_BANDWIDTH, INTMEM_BANDWIDTH };
+
+DEFINE_SPINLOCK(arbiter_lock);
+
+static irqreturn_t crisv32_arbiter_irq(int irq, void *dev_id);
+
+/*
+ * "I'm the arbiter, I know the score.
+ *  From square one I'll be watching all 64."
+ * (memory arbiter slots, that is)
+ *
+ *  Or in other words:
+ * Program the memory arbiter slots for "region" according to what's
+ * in requested_slots[] and active_clients[], while minimizing
+ * latency. A caller may pass a non-zero positive amount for
+ * "unused_slots", which must then be the unallocated, remaining
+ * number of slots, free to hand out to any client.
+ */
+
+static void crisv32_arbiter_config(int region, int unused_slots)
+{
+	int slot;
+	int client;
+	int interval = 0;
+
+	/*
+	 * This vector corresponds to the hardware arbiter slots (see
+	 * the hardware documentation for semantics). We initialize
+	 * each slot with a suitable sentinel value outside the valid
+	 * range {0 .. NBR_OF_CLIENTS - 1} and replace them with
+	 * client indexes. Then it's fed to the hardware.
+	 */
+	s8 val[NBR_OF_SLOTS];
+
+	for (slot = 0; slot < NBR_OF_SLOTS; slot++)
+		val[slot] = -1;
+
+	for (client = 0; client < NBR_OF_CLIENTS; client++) {
+		int pos;
+		/* Allocate the requested non-zero number of slots, but
+		 * also give clients with zero-requests one slot each
+		 * while stocks last. We do the latter here, in client
+		 * order. This makes sure zero-request clients are the
+		 * first to get to any spare slots, else those slots
+		 * could, when bandwidth is allocated close to the limit,
+		 * all be allocated to low-index non-zero-request clients
+		 * in the default-fill loop below. Another positive but
+		 * secondary effect is a somewhat better spread of the
+		 * zero-bandwidth clients in the vector, avoiding some of
+		 * the latency that could otherwise be caused by the
+		 * partitioning of non-zero-bandwidth clients at low
+		 * indexes and zero-bandwidth clients at high
+		 * indexes. (Note that this spreading can only affect the
+		 * unallocated bandwidth.)  All the above only matters for
+		 * memory-intensive situations, of course.
+		 */
+		if (!requested_slots[region][client]) {
+			/*
+			 * Skip inactive clients. Also skip zero-slot
+			 * allocations in this pass when there are no known
+			 * free slots.
+			 */
+			if (!active_clients[region][client]
+			    || unused_slots <= 0)
+				continue;
+
+			unused_slots--;
+
+			/* Only allocate one slot for this client. */
+			interval = NBR_OF_SLOTS;
+		} else
+			interval =
+			    NBR_OF_SLOTS / requested_slots[region][client];
+
+		pos = 0;
+		while (pos < NBR_OF_SLOTS) {
+			if (val[pos] >= 0)
+				pos++;
+			else {
+				val[pos] = client;
+				pos += interval;
+			}
+		}
+	}
+
+	client = 0;
+	for (slot = 0; slot < NBR_OF_SLOTS; slot++) {
+		/*
+		 * Allocate remaining slots in round-robin
+		 * client-number order for active clients. For this
+		 * pass, we ignore requested bandwidth and previous
+		 * allocations.
+		 */
+		if (val[slot] < 0) {
+			int first = client;
+			while (!active_clients[region][client]) {
+				client = (client + 1) % NBR_OF_CLIENTS;
+				if (client == first)
+					break;
+			}
+			val[slot] = client;
+			client = (client + 1) % NBR_OF_CLIENTS;
+		}
+		if (region == EXT_REGION)
+			REG_WR_INT_VECT(marb, regi_marb, rw_ext_slots, slot,
+					val[slot]);
+		else if (region == INT_REGION)
+			REG_WR_INT_VECT(marb, regi_marb, rw_int_slots, slot,
+					val[slot]);
+	}
+}
+
+extern char _stext, _etext;
+
+static void crisv32_arbiter_init(void)
+{
+	static int initialized;
+
+	if (initialized)
+		return;
+
+	initialized = 1;
+
+	/*
+	 * CPU caches are always set to active, but with zero
+	 * bandwidth allocated. It should be ok to allocate zero
+	 * bandwidth for the caches, because DMA for other channels
+	 * will supposedly finish, once their programmed amount is
+	 * done, and then the caches will get access according to the
+	 * "fixed scheme" for unclaimed slots. Though, if for some
+	 * use-case somewhere, there's a maximum CPU latency for
+	 * e.g. some interrupt, we have to start allocating specific
+	 * bandwidth for the CPU caches too.
+	 */
+	active_clients[EXT_REGION][10] = active_clients[EXT_REGION][11] = 1;
+	crisv32_arbiter_config(EXT_REGION, 0);
+	crisv32_arbiter_config(INT_REGION, 0);
+
+	if (request_irq(MEMARB_INTR_VECT, crisv32_arbiter_irq, 0,
+			"arbiter", NULL))
+		printk(KERN_ERR "Couldn't allocate arbiter IRQ\n");
+
+#ifndef CONFIG_ETRAX_KGDB
+	/* Global watch for writes to kernel text segment. */
+	crisv32_arbiter_watch(virt_to_phys(&_stext), &_etext - &_stext,
+			      arbiter_all_clients, arbiter_all_write, NULL);
+#endif
+}
+
+/* Main entry for bandwidth allocation. */
+
+int crisv32_arbiter_allocate_bandwidth(int client, int region,
+				       unsigned long bandwidth)
+{
+	int i;
+	int total_assigned = 0;
+	int total_clients = 0;
+	int req;
+
+	crisv32_arbiter_init();
+
+	for (i = 0; i < NBR_OF_CLIENTS; i++) {
+		total_assigned += requested_slots[region][i];
+		total_clients += active_clients[region][i];
+	}
+
+	/* Avoid division by 0 for 0-bandwidth requests. */
+	req = bandwidth == 0
+	    ? 0 : NBR_OF_SLOTS / (max_bandwidth[region] / bandwidth);
+
+	/*
+	 * We make sure that there are enough slots only for non-zero
+	 * requests. Requesting 0 bandwidth *may* allocate slots,
+	 * though if all bandwidth is allocated, such a client won't
+	 * get any and will have to rely on getting memory access
+	 * according to the fixed scheme that's the default when one
+	 * of the slot-allocated clients doesn't claim their slot.
+	 */
+	if (total_assigned + req > NBR_OF_SLOTS)
+		return -ENOMEM;
+
+	active_clients[region][client] = 1;
+	requested_slots[region][client] = req;
+	crisv32_arbiter_config(region, NBR_OF_SLOTS - total_assigned);
+
+	return 0;
+}
+
+/*
+ * Main entry for bandwidth deallocation.
+ *
+ * Strictly speaking, for a somewhat constant set of clients where
+ * each client gets a constant bandwidth and is just enabled or
+ * disabled (somewhat dynamically), no action is necessary here to
+ * avoid starvation for non-zero-allocation clients, as the allocated
+ * slots will just be unused. However, handing out those unused slots
+ * to active clients avoids needless latency if the "fixed scheme"
+ * would give unclaimed slots to an eager low-index client.
+ */
+
+void crisv32_arbiter_deallocate_bandwidth(int client, int region)
+{
+	int i;
+	int total_assigned = 0;
+
+	requested_slots[region][client] = 0;
+	active_clients[region][client] = 0;
+
+	for (i = 0; i < NBR_OF_CLIENTS; i++)
+		total_assigned += requested_slots[region][i];
+
+	crisv32_arbiter_config(region, NBR_OF_SLOTS - total_assigned);
+}
+
+int crisv32_arbiter_watch(unsigned long start, unsigned long size,
+			  unsigned long clients, unsigned long accesses,
+			  watch_callback *cb)
+{
+	int i;
+
+	crisv32_arbiter_init();
+
+	if (start > 0x80000000) {
+		printk(KERN_ERR "Arbiter: %lX doesn't look like a "
+			"physical address", start);
+		return -EFAULT;
+	}
+
+	spin_lock(&arbiter_lock);
+
+	for (i = 0; i < NUMBER_OF_BP; i++) {
+		if (!watches[i].used) {
+			reg_marb_rw_intr_mask intr_mask =
+			    REG_RD(marb, regi_marb, rw_intr_mask);
+
+			watches[i].used = 1;
+			watches[i].start = start;
+			watches[i].end = start + size;
+			watches[i].cb = cb;
+
+			REG_WR_INT(marb_bp, watches[i].instance, rw_first_addr,
+				   watches[i].start);
+			REG_WR_INT(marb_bp, watches[i].instance, rw_last_addr,
+				   watches[i].end);
+			REG_WR_INT(marb_bp, watches[i].instance, rw_op,
+				   accesses);
+			REG_WR_INT(marb_bp, watches[i].instance, rw_clients,
+				   clients);
+
+			if (i == 0)
+				intr_mask.bp0 = regk_marb_yes;
+			else if (i == 1)
+				intr_mask.bp1 = regk_marb_yes;
+			else if (i == 2)
+				intr_mask.bp2 = regk_marb_yes;
+			else if (i == 3)
+				intr_mask.bp3 = regk_marb_yes;
+
+			REG_WR(marb, regi_marb, rw_intr_mask, intr_mask);
+			spin_unlock(&arbiter_lock);
+
+			return i;
+		}
+	}
+	spin_unlock(&arbiter_lock);
+	return -ENOMEM;
+}
+
+int crisv32_arbiter_unwatch(int id)
+{
+	reg_marb_rw_intr_mask intr_mask = REG_RD(marb, regi_marb, rw_intr_mask);
+
+	crisv32_arbiter_init();
+
+	spin_lock(&arbiter_lock);
+
+	if ((id < 0) || (id >= NUMBER_OF_BP) || (!watches[id].used)) {
+		spin_unlock(&arbiter_lock);
+		return -EINVAL;
+	}
+
+	memset(&watches[id], 0, sizeof(struct crisv32_watch_entry));
+
+	if (id == 0)
+		intr_mask.bp0 = regk_marb_no;
+	else if (id == 1)
+		intr_mask.bp1 = regk_marb_no;
+	else if (id == 2)
+		intr_mask.bp2 = regk_marb_no;
+	else if (id == 3)
+		intr_mask.bp3 = regk_marb_no;
+
+	REG_WR(marb, regi_marb, rw_intr_mask, intr_mask);
+
+	spin_unlock(&arbiter_lock);
+	return 0;
+}
+
+extern void show_registers(struct pt_regs *regs);
+
+static irqreturn_t crisv32_arbiter_irq(int irq, void *dev_id)
+{
+	reg_marb_r_masked_intr masked_intr =
+	    REG_RD(marb, regi_marb, r_masked_intr);
+	reg_marb_bp_r_brk_clients r_clients;
+	reg_marb_bp_r_brk_addr r_addr;
+	reg_marb_bp_r_brk_op r_op;
+	reg_marb_bp_r_brk_first_client r_first;
+	reg_marb_bp_r_brk_size r_size;
+	reg_marb_bp_rw_ack ack = { 0 };
+	reg_marb_rw_ack_intr ack_intr = {
+		.bp0 = 1, .bp1 = 1, .bp2 = 1, .bp3 = 1
+	};
+	struct crisv32_watch_entry *watch;
+
+	if (masked_intr.bp0) {
+		watch = &watches[0];
+		ack_intr.bp0 = regk_marb_yes;
+	} else if (masked_intr.bp1) {
+		watch = &watches[1];
+		ack_intr.bp1 = regk_marb_yes;
+	} else if (masked_intr.bp2) {
+		watch = &watches[2];
+		ack_intr.bp2 = regk_marb_yes;
+	} else if (masked_intr.bp3) {
+		watch = &watches[3];
+		ack_intr.bp3 = regk_marb_yes;
+	} else {
+		return IRQ_NONE;
+	}
+
+	/* Retrieve all useful information and print it. */
+	r_clients = REG_RD(marb_bp, watch->instance, r_brk_clients);
+	r_addr = REG_RD(marb_bp, watch->instance, r_brk_addr);
+	r_op = REG_RD(marb_bp, watch->instance, r_brk_op);
+	r_first = REG_RD(marb_bp, watch->instance, r_brk_first_client);
+	r_size = REG_RD(marb_bp, watch->instance, r_brk_size);
+
+	printk(KERN_INFO "Arbiter IRQ\n");
+	printk(KERN_INFO "Clients %X addr %X op %X first %X size %X\n",
+	       REG_TYPE_CONV(int, reg_marb_bp_r_brk_clients, r_clients),
+	       REG_TYPE_CONV(int, reg_marb_bp_r_brk_addr, r_addr),
+	       REG_TYPE_CONV(int, reg_marb_bp_r_brk_op, r_op),
+	       REG_TYPE_CONV(int, reg_marb_bp_r_brk_first_client, r_first),
+	       REG_TYPE_CONV(int, reg_marb_bp_r_brk_size, r_size));
+
+	REG_WR(marb_bp, watch->instance, rw_ack, ack);
+	REG_WR(marb, regi_marb, rw_ack_intr, ack_intr);
+
+	printk(KERN_INFO "IRQ occurred at %lX\n", get_irq_regs()->erp);
+
+	if (watch->cb)
+		watch->cb();
+
+	return IRQ_HANDLED;
+}