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author | 2015-08-04 12:17:53 -0700 | |
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committer | 2015-08-04 15:44:42 -0700 | |
commit | 9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch) | |
tree | 1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/cris/arch-v32/mach-fs/arbiter.c | |
parent | 98260f3884f4a202f9ca5eabed40b1354c489b29 (diff) |
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base.
It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:
commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Sat Jul 25 12:13:34 2015 +0200
Prepare v4.1.3-rt3
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.
Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/cris/arch-v32/mach-fs/arbiter.c')
-rw-r--r-- | kernel/arch/cris/arch-v32/mach-fs/arbiter.c | 404 |
1 files changed, 404 insertions, 0 deletions
diff --git a/kernel/arch/cris/arch-v32/mach-fs/arbiter.c b/kernel/arch/cris/arch-v32/mach-fs/arbiter.c new file mode 100644 index 000000000..c97f4d812 --- /dev/null +++ b/kernel/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; +} |