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+/*
+ * File: arch/blackfin/mach-common/cplbmgtr.S
+ * Based on:
+ * Author: LG Soft India
+ *
+ * Created: ?
+ * Description: CPLB replacement routine for CPLB mismatch
+ *
+ * Modified:
+ * Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Bugs: Enter bugs at http://blackfin.uclinux.org/
+ *
+ * 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, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/* Usage: int _cplb_mgr(is_data_miss,int enable_cache)
+ * is_data_miss==2 => Mark as Dirty, write to the clean data page
+ * is_data_miss==1 => Replace a data CPLB.
+ * is_data_miss==0 => Replace an instruction CPLB.
+ *
+ * Returns:
+ * CPLB_RELOADED => Successfully updated CPLB table.
+ * CPLB_NO_UNLOCKED => All CPLBs are locked, so cannot be evicted.
+ * This indicates that the CPLBs in the configuration
+ * tablei are badly configured, as this should never
+ * occur.
+ * CPLB_NO_ADDR_MATCH => The address being accessed, that triggered the
+ * exception, is not covered by any of the CPLBs in
+ * the configuration table. The application is
+ * presumably misbehaving.
+ * CPLB_PROT_VIOL => The address being accessed, that triggered the
+ * exception, was not a first-write to a clean Write
+ * Back Data page, and so presumably is a genuine
+ * violation of the page's protection attributes.
+ * The application is misbehaving.
+ */
+
+#include <linux/linkage.h>
+#include <asm/blackfin.h>
+#include <asm/cplb.h>
+
+#ifdef CONFIG_EXCPT_IRQ_SYSC_L1
+.section .l1.text
+#else
+.text
+#endif
+
+.align 2;
+ENTRY(_cplb_mgr)
+
+ [--SP]=( R7:4,P5:3 );
+
+ CC = R0 == 2;
+ IF CC JUMP .Ldcplb_write;
+
+ CC = R0 == 0;
+ IF !CC JUMP .Ldcplb_miss_compare;
+
+ /* ICPLB Miss Exception. We need to choose one of the
+ * currently-installed CPLBs, and replace it with one
+ * from the configuration table.
+ */
+
+ P4.L = (ICPLB_FAULT_ADDR & 0xFFFF);
+ P4.H = (ICPLB_FAULT_ADDR >> 16);
+
+ P1 = 16;
+ P5.L = _page_size_table;
+ P5.H = _page_size_table;
+
+ P0.L = (ICPLB_DATA0 & 0xFFFF);
+ P0.H = (ICPLB_DATA0 >> 16);
+ R4 = [P4]; /* Get faulting address*/
+ R6 = 64; /* Advance past the fault address, which*/
+ R6 = R6 + R4; /* we'll use if we find a match*/
+ R3 = ((16 << 8) | 2); /* Extract mask, bits 16 and 17.*/
+
+ R5 = 0;
+.Lisearch:
+
+ R1 = [P0-0x100]; /* Address for this CPLB */
+
+ R0 = [P0++]; /* Info for this CPLB*/
+ CC = BITTST(R0,0); /* Is the CPLB valid?*/
+ IF !CC JUMP .Lnomatch; /* Skip it, if not.*/
+ CC = R4 < R1(IU); /* If fault address less than page start*/
+ IF CC JUMP .Lnomatch; /* then skip this one.*/
+ R2 = EXTRACT(R0,R3.L) (Z); /* Get page size*/
+ P1 = R2;
+ P1 = P5 + (P1<<2); /* index into page-size table*/
+ R2 = [P1]; /* Get the page size*/
+ R1 = R1 + R2; /* and add to page start, to get page end*/
+ CC = R4 < R1(IU); /* and see whether fault addr is in page.*/
+ IF !CC R4 = R6; /* If so, advance the address and finish loop.*/
+ IF !CC JUMP .Lisearch_done;
+.Lnomatch:
+ /* Go around again*/
+ R5 += 1;
+ CC = BITTST(R5, 4); /* i.e CC = R5 >= 16*/
+ IF !CC JUMP .Lisearch;
+
+.Lisearch_done:
+ I0 = R4; /* Fault address we'll search for*/
+
+ /* set up pointers */
+ P0.L = (ICPLB_DATA0 & 0xFFFF);
+ P0.H = (ICPLB_DATA0 >> 16);
+
+ /* The replacement procedure for ICPLBs */
+
+ P4.L = (IMEM_CONTROL & 0xFFFF);
+ P4.H = (IMEM_CONTROL >> 16);
+
+ /* disable cplbs */
+ R5 = [P4]; /* Control Register*/
+ BITCLR(R5,ENICPLB_P);
+ CLI R1;
+ SSYNC; /* SSYNC required before writing to IMEM_CONTROL. */
+ .align 8;
+ [P4] = R5;
+ SSYNC;
+ STI R1;
+
+ R1 = -1; /* end point comparison */
+ R3 = 16; /* counter */
+
+ /* Search through CPLBs for first non-locked entry */
+ /* Overwrite it by moving everyone else up by 1 */
+.Licheck_lock:
+ R0 = [P0++];
+ R3 = R3 + R1;
+ CC = R3 == R1;
+ IF CC JUMP .Lall_locked;
+ CC = BITTST(R0, 0); /* an invalid entry is good */
+ IF !CC JUMP .Lifound_victim;
+ CC = BITTST(R0,1); /* but a locked entry isn't */
+ IF CC JUMP .Licheck_lock;
+
+.Lifound_victim:
+#ifdef CONFIG_CPLB_INFO
+ R7 = [P0 - 0x104];
+ P2.L = _ipdt_table;
+ P2.H = _ipdt_table;
+ P3.L = _ipdt_swapcount_table;
+ P3.H = _ipdt_swapcount_table;
+ P3 += -4;
+.Licount:
+ R2 = [P2]; /* address from config table */
+ P2 += 8;
+ P3 += 8;
+ CC = R2==-1;
+ IF CC JUMP .Licount_done;
+ CC = R7==R2;
+ IF !CC JUMP .Licount;
+ R7 = [P3];
+ R7 += 1;
+ [P3] = R7;
+ CSYNC;
+.Licount_done:
+#endif
+ LC0=R3;
+ LSETUP(.Lis_move,.Lie_move) LC0;
+.Lis_move:
+ R0 = [P0];
+ [P0 - 4] = R0;
+ R0 = [P0 - 0x100];
+ [P0-0x104] = R0;
+.Lie_move:P0+=4;
+
+ /* We've made space in the ICPLB table, so that ICPLB15
+ * is now free to be overwritten. Next, we have to determine
+ * which CPLB we need to install, from the configuration
+ * table. This is a matter of getting the start-of-page
+ * addresses and page-lengths from the config table, and
+ * determining whether the fault address falls within that
+ * range.
+ */
+
+ P2.L = _ipdt_table;
+ P2.H = _ipdt_table;
+#ifdef CONFIG_CPLB_INFO
+ P3.L = _ipdt_swapcount_table;
+ P3.H = _ipdt_swapcount_table;
+ P3 += -8;
+#endif
+ P0.L = _page_size_table;
+ P0.H = _page_size_table;
+
+ /* Retrieve our fault address (which may have been advanced
+ * because the faulting instruction crossed a page boundary).
+ */
+
+ R0 = I0;
+
+ /* An extraction pattern, to get the page-size bits from
+ * the CPLB data entry. Bits 16-17, so two bits at posn 16.
+ */
+
+ R1 = ((16<<8)|2);
+.Linext: R4 = [P2++]; /* address from config table */
+ R2 = [P2++]; /* data from config table */
+#ifdef CONFIG_CPLB_INFO
+ P3 += 8;
+#endif
+
+ CC = R4 == -1; /* End of config table*/
+ IF CC JUMP .Lno_page_in_table;
+
+ /* See if failed address > start address */
+ CC = R4 <= R0(IU);
+ IF !CC JUMP .Linext;
+
+ /* extract page size (17:16)*/
+ R3 = EXTRACT(R2, R1.L) (Z);
+
+ /* add page size to addr to get range */
+
+ P5 = R3;
+ P5 = P0 + (P5 << 2); /* scaled, for int access*/
+ R3 = [P5];
+ R3 = R3 + R4;
+
+ /* See if failed address < (start address + page size) */
+ CC = R0 < R3(IU);
+ IF !CC JUMP .Linext;
+
+ /* We've found a CPLB in the config table that covers
+ * the faulting address, so install this CPLB into the
+ * last entry of the table.
+ */
+
+ P1.L = (ICPLB_DATA15 & 0xFFFF); /* ICPLB_DATA15 */
+ P1.H = (ICPLB_DATA15 >> 16);
+ [P1] = R2;
+ [P1-0x100] = R4;
+#ifdef CONFIG_CPLB_INFO
+ R3 = [P3];
+ R3 += 1;
+ [P3] = R3;
+#endif
+
+ /* P4 points to IMEM_CONTROL, and R5 contains its old
+ * value, after we disabled ICPLBS. Re-enable them.
+ */
+
+ BITSET(R5,ENICPLB_P);
+ CLI R2;
+ SSYNC; /* SSYNC required before writing to IMEM_CONTROL. */
+ .align 8;
+ [P4] = R5;
+ SSYNC;
+ STI R2;
+
+ ( R7:4,P5:3 ) = [SP++];
+ R0 = CPLB_RELOADED;
+ RTS;
+
+/* FAILED CASES*/
+.Lno_page_in_table:
+ ( R7:4,P5:3 ) = [SP++];
+ R0 = CPLB_NO_ADDR_MATCH;
+ RTS;
+.Lall_locked:
+ ( R7:4,P5:3 ) = [SP++];
+ R0 = CPLB_NO_UNLOCKED;
+ RTS;
+.Lprot_violation:
+ ( R7:4,P5:3 ) = [SP++];
+ R0 = CPLB_PROT_VIOL;
+ RTS;
+
+.Ldcplb_write:
+
+ /* if a DCPLB is marked as write-back (CPLB_WT==0), and
+ * it is clean (CPLB_DIRTY==0), then a write to the
+ * CPLB's page triggers a protection violation. We have to
+ * mark the CPLB as dirty, to indicate that there are
+ * pending writes associated with the CPLB.
+ */
+
+ P4.L = (DCPLB_STATUS & 0xFFFF);
+ P4.H = (DCPLB_STATUS >> 16);
+ P3.L = (DCPLB_DATA0 & 0xFFFF);
+ P3.H = (DCPLB_DATA0 >> 16);
+ R5 = [P4];
+
+ /* A protection violation can be caused by more than just writes
+ * to a clean WB page, so we have to ensure that:
+ * - It's a write
+ * - to a clean WB page
+ * - and is allowed in the mode the access occurred.
+ */
+
+ CC = BITTST(R5, 16); /* ensure it was a write*/
+ IF !CC JUMP .Lprot_violation;
+
+ /* to check the rest, we have to retrieve the DCPLB.*/
+
+ /* The low half of DCPLB_STATUS is a bit mask*/
+
+ R2 = R5.L (Z); /* indicating which CPLB triggered the event.*/
+ R3 = 30; /* so we can use this to determine the offset*/
+ R2.L = SIGNBITS R2;
+ R2 = R2.L (Z); /* into the DCPLB table.*/
+ R3 = R3 - R2;
+ P4 = R3;
+ P3 = P3 + (P4<<2);
+ R3 = [P3]; /* Retrieve the CPLB*/
+
+ /* Now we can check whether it's a clean WB page*/
+
+ CC = BITTST(R3, 14); /* 0==WB, 1==WT*/
+ IF CC JUMP .Lprot_violation;
+ CC = BITTST(R3, 7); /* 0 == clean, 1 == dirty*/
+ IF CC JUMP .Lprot_violation;
+
+ /* Check whether the write is allowed in the mode that was active.*/
+
+ R2 = 1<<3; /* checking write in user mode*/
+ CC = BITTST(R5, 17); /* 0==was user, 1==was super*/
+ R5 = CC;
+ R2 <<= R5; /* if was super, check write in super mode*/
+ R2 = R3 & R2;
+ CC = R2 == 0;
+ IF CC JUMP .Lprot_violation;
+
+ /* It's a genuine write-to-clean-page.*/
+
+ BITSET(R3, 7); /* mark as dirty*/
+ [P3] = R3; /* and write back.*/
+ NOP;
+ CSYNC;
+ ( R7:4,P5:3 ) = [SP++];
+ R0 = CPLB_RELOADED;
+ RTS;
+
+.Ldcplb_miss_compare:
+
+ /* Data CPLB Miss event. We need to choose a CPLB to
+ * evict, and then locate a new CPLB to install from the
+ * config table, that covers the faulting address.
+ */
+
+ P1.L = (DCPLB_DATA15 & 0xFFFF);
+ P1.H = (DCPLB_DATA15 >> 16);
+
+ P4.L = (DCPLB_FAULT_ADDR & 0xFFFF);
+ P4.H = (DCPLB_FAULT_ADDR >> 16);
+ R4 = [P4];
+ I0 = R4;
+
+ /* The replacement procedure for DCPLBs*/
+
+ R6 = R1; /* Save for later*/
+
+ /* Turn off CPLBs while we work.*/
+ P4.L = (DMEM_CONTROL & 0xFFFF);
+ P4.H = (DMEM_CONTROL >> 16);
+ R5 = [P4];
+ BITCLR(R5,ENDCPLB_P);
+ CLI R0;
+ SSYNC; /* SSYNC required before writing to DMEM_CONTROL. */
+ .align 8;
+ [P4] = R5;
+ SSYNC;
+ STI R0;
+
+ /* Start looking for a CPLB to evict. Our order of preference
+ * is: invalid CPLBs, clean CPLBs, dirty CPLBs. Locked CPLBs
+ * are no good.
+ */
+
+ I1.L = (DCPLB_DATA0 & 0xFFFF);
+ I1.H = (DCPLB_DATA0 >> 16);
+ P1 = 2;
+ P2 = 16;
+ I2.L = _dcplb_preference;
+ I2.H = _dcplb_preference;
+ LSETUP(.Lsdsearch1, .Ledsearch1) LC0 = P1;
+.Lsdsearch1:
+ R0 = [I2++]; /* Get the bits we're interested in*/
+ P0 = I1; /* Go back to start of table*/
+ LSETUP (.Lsdsearch2, .Ledsearch2) LC1 = P2;
+.Lsdsearch2:
+ R1 = [P0++]; /* Fetch each installed CPLB in turn*/
+ R2 = R1 & R0; /* and test for interesting bits.*/
+ CC = R2 == 0; /* If none are set, it'll do.*/
+ IF !CC JUMP .Lskip_stack_check;
+
+ R2 = [P0 - 0x104]; /* R2 - PageStart */
+ P3.L = _page_size_table; /* retrieve end address */
+ P3.H = _page_size_table; /* retrieve end address */
+ R3 = 0x1002; /* 16th - position, 2 bits -length */
+#ifdef ANOMALY_05000209
+ nop; /* Anomaly 05000209 */
+#endif
+ R7 = EXTRACT(R1,R3.l);
+ R7 = R7 << 2; /* Page size index offset */
+ P5 = R7;
+ P3 = P3 + P5;
+ R7 = [P3]; /* page size in bytes */
+
+ R7 = R2 + R7; /* R7 - PageEnd */
+ R4 = SP; /* Test SP is in range */
+
+ CC = R7 < R4; /* if PageEnd < SP */
+ IF CC JUMP .Ldfound_victim;
+ R3 = 0x284; /* stack length from start of trap till
+ * the point.
+ * 20 stack locations for future modifications
+ */
+ R4 = R4 + R3;
+ CC = R4 < R2; /* if SP + stacklen < PageStart */
+ IF CC JUMP .Ldfound_victim;
+.Lskip_stack_check:
+
+.Ledsearch2: NOP;
+.Ledsearch1: NOP;
+
+ /* If we got here, we didn't find a DCPLB we considered
+ * replacable, which means all of them were locked.
+ */
+
+ JUMP .Lall_locked;
+.Ldfound_victim:
+
+#ifdef CONFIG_CPLB_INFO
+ R7 = [P0 - 0x104];
+ P2.L = _dpdt_table;
+ P2.H = _dpdt_table;
+ P3.L = _dpdt_swapcount_table;
+ P3.H = _dpdt_swapcount_table;
+ P3 += -4;
+.Ldicount:
+ R2 = [P2];
+ P2 += 8;
+ P3 += 8;
+ CC = R2==-1;
+ IF CC JUMP .Ldicount_done;
+ CC = R7==R2;
+ IF !CC JUMP .Ldicount;
+ R7 = [P3];
+ R7 += 1;
+ [P3] = R7;
+.Ldicount_done:
+#endif
+
+ /* Clean down the hardware loops*/
+ R2 = 0;
+ LC1 = R2;
+ LC0 = R2;
+
+ /* There's a suitable victim in [P0-4] (because we've
+ * advanced already).
+ */
+
+.LDdoverwrite:
+
+ /* [P0-4] is a suitable victim CPLB, so we want to
+ * overwrite it by moving all the following CPLBs
+ * one space closer to the start.
+ */
+
+ R1.L = (DCPLB_DATA16 & 0xFFFF); /* DCPLB_DATA15 + 4 */
+ R1.H = (DCPLB_DATA16 >> 16);
+ R0 = P0;
+
+ /* If the victim happens to be in DCPLB15,
+ * we don't need to move anything.
+ */
+
+ CC = R1 == R0;
+ IF CC JUMP .Lde_moved;
+ R1 = R1 - R0;
+ R1 >>= 2;
+ P1 = R1;
+ LSETUP(.Lds_move, .Lde_move) LC0=P1;
+.Lds_move:
+ R0 = [P0++]; /* move data */
+ [P0 - 8] = R0;
+ R0 = [P0-0x104] /* move address */
+.Lde_move: [P0-0x108] = R0;
+
+ /* We've now made space in DCPLB15 for the new CPLB to be
+ * installed. The next stage is to locate a CPLB in the
+ * config table that covers the faulting address.
+ */
+
+.Lde_moved:NOP;
+ R0 = I0; /* Our faulting address */
+
+ P2.L = _dpdt_table;
+ P2.H = _dpdt_table;
+#ifdef CONFIG_CPLB_INFO
+ P3.L = _dpdt_swapcount_table;
+ P3.H = _dpdt_swapcount_table;
+ P3 += -8;
+#endif
+
+ P1.L = _page_size_table;
+ P1.H = _page_size_table;
+
+ /* An extraction pattern, to retrieve bits 17:16.*/
+
+ R1 = (16<<8)|2;
+.Ldnext: R4 = [P2++]; /* address */
+ R2 = [P2++]; /* data */
+#ifdef CONFIG_CPLB_INFO
+ P3 += 8;
+#endif
+
+ CC = R4 == -1;
+ IF CC JUMP .Lno_page_in_table;
+
+ /* See if failed address > start address */
+ CC = R4 <= R0(IU);
+ IF !CC JUMP .Ldnext;
+
+ /* extract page size (17:16)*/
+ R3 = EXTRACT(R2, R1.L) (Z);
+
+ /* add page size to addr to get range */
+
+ P5 = R3;
+ P5 = P1 + (P5 << 2);
+ R3 = [P5];
+ R3 = R3 + R4;
+
+ /* See if failed address < (start address + page size) */
+ CC = R0 < R3(IU);
+ IF !CC JUMP .Ldnext;
+
+ /* We've found the CPLB that should be installed, so
+ * write it into CPLB15, masking off any caching bits
+ * if necessary.
+ */
+
+ P1.L = (DCPLB_DATA15 & 0xFFFF);
+ P1.H = (DCPLB_DATA15 >> 16);
+
+ /* If the DCPLB has cache bits set, but caching hasn't
+ * been enabled, then we want to mask off the cache-in-L1
+ * bit before installing. Moreover, if caching is off, we
+ * also want to ensure that the DCPLB has WT mode set, rather
+ * than WB, since WB pages still trigger first-write exceptions
+ * even when not caching is off, and the page isn't marked as
+ * cachable. Finally, we could mark the page as clean, not dirty,
+ * but we choose to leave that decision to the user; if the user
+ * chooses to have a CPLB pre-defined as dirty, then they always
+ * pay the cost of flushing during eviction, but don't pay the
+ * cost of first-write exceptions to mark the page as dirty.
+ */
+
+#ifdef CONFIG_BLKFIN_WT
+ BITSET(R6, 14); /* Set WT*/
+#endif
+
+ [P1] = R2;
+ [P1-0x100] = R4;
+#ifdef CONFIG_CPLB_INFO
+ R3 = [P3];
+ R3 += 1;
+ [P3] = R3;
+#endif
+
+ /* We've installed the CPLB, so re-enable CPLBs. P4
+ * points to DMEM_CONTROL, and R5 is the value we
+ * last wrote to it, when we were disabling CPLBs.
+ */
+
+ BITSET(R5,ENDCPLB_P);
+ CLI R2;
+ .align 8;
+ [P4] = R5;
+ SSYNC;
+ STI R2;
+
+ ( R7:4,P5:3 ) = [SP++];
+ R0 = CPLB_RELOADED;
+ RTS;
+
+.data
+.align 4;
+_page_size_table:
+.byte4 0x00000400; /* 1K */
+.byte4 0x00001000; /* 4K */
+.byte4 0x00100000; /* 1M */
+.byte4 0x00400000; /* 4M */
+
+.align 4;
+_dcplb_preference:
+.byte4 0x00000001; /* valid bit */
+.byte4 0x00000002; /* lock bit */