/*
   *              GRU KERNEL MCS INSTRUCTIONS
   *
   *  Copyright (c) 2008 Silicon Graphics, Inc.  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; either version 2 of the License, or
   *  (at your option) any later version.
   *
   *  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.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */
  
  #include <linux/kernel.h>
  #include "gru.h"
  #include "grulib.h"
  #include "grutables.h"
  
  /* 10 sec */
  #ifdef CONFIG_IA64
  #include <asm/processor.h>
  #define GRU_OPERATION_TIMEOUT	(((cycles_t) local_cpu_data->itc_freq)*10)
  #define CLKS2NSEC(c)		((c) *1000000000 / local_cpu_data->itc_freq)
  #else
  #include <asm/tsc.h>
  #define GRU_OPERATION_TIMEOUT	((cycles_t) tsc_khz*10*1000)
  #define CLKS2NSEC(c)		((c) * 1000000 / tsc_khz)
  #endif
  
  /* Extract the status field from a kernel handle */
  #define GET_MSEG_HANDLE_STATUS(h)	(((*(unsigned long *)(h)) >> 16) & 3)
  
  struct mcs_op_statistic mcs_op_statistics[mcsop_last];
  
  static void update_mcs_stats(enum mcs_op op, unsigned long clks)
  {
  	unsigned long nsec;
  
  	nsec = CLKS2NSEC(clks);
  	atomic_long_inc(&mcs_op_statistics[op].count);
  	atomic_long_add(nsec, &mcs_op_statistics[op].total);
  	if (mcs_op_statistics[op].max < nsec)
  		mcs_op_statistics[op].max = nsec;
  }
  
  static void start_instruction(void *h)
  {
  	unsigned long *w0 = h;
  
  	wmb();		/* setting CMD/STATUS bits must be last */
  	*w0 = *w0 | 0x20001;
  	gru_flush_cache(h);
  }
  
  static void report_instruction_timeout(void *h)
  {
  	unsigned long goff = GSEGPOFF((unsigned long)h);
  	char *id = "???";
  
  	if (TYPE_IS(CCH, goff))
  		id = "CCH";
  	else if (TYPE_IS(TGH, goff))
  		id = "TGH";
  	else if (TYPE_IS(TFH, goff))
  		id = "TFH";
  
  	panic(KERN_ALERT "GRU %p (%s) is malfunctioning
  ", h, id);
  }
  
  static int wait_instruction_complete(void *h, enum mcs_op opc)
  {
  	int status;
  	unsigned long start_time = get_cycles();
  
  	while (1) {
  		cpu_relax();
  		status = GET_MSEG_HANDLE_STATUS(h);
  		if (status != CCHSTATUS_ACTIVE)
  			break;
  		if (GRU_OPERATION_TIMEOUT < (get_cycles() - start_time)) {
  			report_instruction_timeout(h);
  			start_time = get_cycles();
  		}
  	}
  	if (gru_options & OPT_STATS)
  		update_mcs_stats(opc, get_cycles() - start_time);
  	return status;
  }
  
  int cch_allocate(struct gru_context_configuration_handle *cch)
  {
  	int ret;
  
  	cch->opc = CCHOP_ALLOCATE;
  	start_instruction(cch);
  	ret = wait_instruction_complete(cch, cchop_allocate);
  
  	/*
  	 * Stop speculation into the GSEG being mapped by the previous ALLOCATE.
  	 * The GSEG memory does not exist until the ALLOCATE completes.
  	 */
  	sync_core();
  	return ret;
  }
  
  int cch_start(struct gru_context_configuration_handle *cch)
  {
  	cch->opc = CCHOP_START;
  	start_instruction(cch);
  	return wait_instruction_complete(cch, cchop_start);
  }
  
  int cch_interrupt(struct gru_context_configuration_handle *cch)
  {
  	cch->opc = CCHOP_INTERRUPT;
  	start_instruction(cch);
  	return wait_instruction_complete(cch, cchop_interrupt);
  }
  
  int cch_deallocate(struct gru_context_configuration_handle *cch)
  {
  	int ret;
  
  	cch->opc = CCHOP_DEALLOCATE;
  	start_instruction(cch);
  	ret = wait_instruction_complete(cch, cchop_deallocate);
  
  	/*
  	 * Stop speculation into the GSEG being unmapped by the previous
  	 * DEALLOCATE.
  	 */
  	sync_core();
  	return ret;
  }
  
  int cch_interrupt_sync(struct gru_context_configuration_handle
  				     *cch)
  {
  	cch->opc = CCHOP_INTERRUPT_SYNC;
  	start_instruction(cch);
  	return wait_instruction_complete(cch, cchop_interrupt_sync);
  }
  
  int tgh_invalidate(struct gru_tlb_global_handle *tgh,
  				 unsigned long vaddr, unsigned long vaddrmask,
  				 int asid, int pagesize, int global, int n,
  				 unsigned short ctxbitmap)
  {
  	tgh->vaddr = vaddr;
  	tgh->asid = asid;
  	tgh->pagesize = pagesize;
  	tgh->n = n;
  	tgh->global = global;
  	tgh->vaddrmask = vaddrmask;
  	tgh->ctxbitmap = ctxbitmap;
  	tgh->opc = TGHOP_TLBINV;
  	start_instruction(tgh);
  	return wait_instruction_complete(tgh, tghop_invalidate);
  }
  
  int tfh_write_only(struct gru_tlb_fault_handle *tfh,
  				  unsigned long paddr, int gaa,
  				  unsigned long vaddr, int asid, int dirty,
  				  int pagesize)
  {
  	tfh->fillasid = asid;
  	tfh->fillvaddr = vaddr;
  	tfh->pfn = paddr >> GRU_PADDR_SHIFT;
  	tfh->gaa = gaa;
  	tfh->dirty = dirty;
  	tfh->pagesize = pagesize;
  	tfh->opc = TFHOP_WRITE_ONLY;
  	start_instruction(tfh);
  	return wait_instruction_complete(tfh, tfhop_write_only);
  }
  
  void tfh_write_restart(struct gru_tlb_fault_handle *tfh,
  				     unsigned long paddr, int gaa,
  				     unsigned long vaddr, int asid, int dirty,
  				     int pagesize)
  {
  	tfh->fillasid = asid;
  	tfh->fillvaddr = vaddr;
  	tfh->pfn = paddr >> GRU_PADDR_SHIFT;
  	tfh->gaa = gaa;
  	tfh->dirty = dirty;
  	tfh->pagesize = pagesize;
  	tfh->opc = TFHOP_WRITE_RESTART;
  	start_instruction(tfh);
  }
  
  void tfh_restart(struct gru_tlb_fault_handle *tfh)
  {
  	tfh->opc = TFHOP_RESTART;
  	start_instruction(tfh);
  }
  
  void tfh_user_polling_mode(struct gru_tlb_fault_handle *tfh)
  {
  	tfh->opc = TFHOP_USER_POLLING_MODE;
  	start_instruction(tfh);
  }
  
  void tfh_exception(struct gru_tlb_fault_handle *tfh)
  {
  	tfh->opc = TFHOP_EXCEPTION;
  	start_instruction(tfh);
  }