diff options
Diffstat (limited to 'cpu/blackfin/flush.S')
| -rw-r--r-- | cpu/blackfin/flush.S | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/cpu/blackfin/flush.S b/cpu/blackfin/flush.S new file mode 100644 index 0000000..8072b86 --- /dev/null +++ b/cpu/blackfin/flush.S @@ -0,0 +1,230 @@ +/* flush.S - low level cache flushing routines + * Copyright (C) 2003-2007 Analog Devices Inc. + * Licensed under the GPL-2 or later. + */ + +#include <config.h> +#include <asm/blackfin.h> +#include <asm/cplb.h> +#include <asm/mach-common/bits/mpu.h> + +.text + +/* This is an external function being called by the user + * application through __flush_cache_all. Currently this function + * serves the purpose of flushing all the pending writes in + * in the data cache. + */ + +ENTRY(_flush_data_cache) + [--SP] = ( R7:6, P5:4 ); + LINK 12; + SP += -12; + P5.H = HI(DCPLB_ADDR0); + P5.L = LO(DCPLB_ADDR0); + P4.H = HI(DCPLB_DATA0); + P4.L = LO(DCPLB_DATA0); + R7 = CPLB_VALID | CPLB_L1_CHBL | CPLB_DIRTY (Z); + R6 = 16; +.Lnext: R0 = [P5++]; + R1 = [P4++]; + CC = BITTST(R1, 14); /* Is it write-through?*/ + IF CC JUMP .Lskip; /* If so, ignore it.*/ + R2 = R1 & R7; /* Is it a dirty, cached page?*/ + CC = R2; + IF !CC JUMP .Lskip; /* If not, ignore it.*/ + [--SP] = RETS; + CALL _dcplb_flush; /* R0 = page, R1 = data*/ + RETS = [SP++]; +.Lskip: R6 += -1; + CC = R6; + IF CC JUMP .Lnext; + SSYNC; + SP += 12; + UNLINK; + ( R7:6, P5:4 ) = [SP++]; + RTS; +ENDPROC(_flush_data_cache) + +/* This is an internal function to flush all pending + * writes in the cache associated with a particular DCPLB. + * + * R0 - page's start address + * R1 - CPLB's data field. + */ + +.align 2 +ENTRY(_dcplb_flush) + [--SP] = ( R7:0, P5:0 ); + [--SP] = LC0; + [--SP] = LT0; + [--SP] = LB0; + [--SP] = LC1; + [--SP] = LT1; + [--SP] = LB1; + + /* If it's a 1K or 4K page, then it's quickest to + * just systematically flush all the addresses in + * the page, regardless of whether they're in the + * cache, or dirty. If it's a 1M or 4M page, there + * are too many addresses, and we have to search the + * cache for lines corresponding to the page. + */ + + CC = BITTST(R1, 17); /* 1MB or 4MB */ + IF !CC JUMP .Ldflush_whole_page; + + /* We're only interested in the page's size, so extract + * this from the CPLB (bits 17:16), and scale to give an + * offset into the page_size and page_prefix tables. + */ + + R1 <<= 14; + R1 >>= 30; + R1 <<= 2; + + /* The page could be mapped into Bank A or Bank B, depending + * on (a) whether both banks are configured as cache, and + * (b) on whether address bit A[x] is set. x is determined + * by DCBS in DMEM_CONTROL + */ + + R2 = 0; /* Default to Bank A (Bank B would be 1)*/ + + P0.L = LO(DMEM_CONTROL); + P0.H = HI(DMEM_CONTROL); + + R3 = [P0]; /* If Bank B is not enabled as cache*/ + CC = BITTST(R3, 2); /* then Bank A is our only option.*/ + IF CC JUMP .Lbank_chosen; + + R4 = 1<<14; /* If DCBS==0, use A[14].*/ + R5 = R4 << 7; /* If DCBS==1, use A[23];*/ + CC = BITTST(R3, 4); + IF CC R4 = R5; /* R4 now has either bit 14 or bit 23 set.*/ + R5 = R0 & R4; /* Use it to test the Page address*/ + CC = R5; /* and if that bit is set, we use Bank B,*/ + R2 = CC; /* else we use Bank A.*/ + R2 <<= 23; /* The Bank selection's at posn 23.*/ + +.Lbank_chosen: + + /* We can also determine the sub-bank used, because this is + * taken from bits 13:12 of the address. + */ + + R3 = ((12<<8)|2); /* Extraction pattern */ + nop; /*Anamoly 05000209*/ + R4 = EXTRACT(R0, R3.L) (Z); /* Extract bits*/ + /* Save in extraction pattern for later deposit.*/ + R3.H = R4.L << 0; + + /* So: + * R0 = Page start + * R1 = Page length (actually, offset into size/prefix tables) + * R2 = Bank select mask + * R3 = sub-bank deposit values + * + * The cache has 2 Ways, and 64 sets, so we iterate through + * the sets, accessing the tag for each Way, for our Bank and + * sub-bank, looking for dirty, valid tags that match our + * address prefix. + */ + + P5.L = LO(DTEST_COMMAND); + P5.H = HI(DTEST_COMMAND); + P4.L = LO(DTEST_DATA0); + P4.H = HI(DTEST_DATA0); + + P0.L = page_prefix_table; + P0.H = page_prefix_table; + P1 = R1; + R5 = 0; /* Set counter*/ + P0 = P1 + P0; + R4 = [P0]; /* This is the address prefix*/ + + + /* We're reading (bit 1==0) the tag (bit 2==0), and we + * don't care about which double-word, since we're only + * fetching tags, so we only have to set Set, Bank, + * Sub-bank and Way. + */ + + P2 = 2; + LSETUP (.Lfs1, .Lfe1) LC1 = P2; +.Lfs1: P0 = 64; /* iterate over all sets*/ + LSETUP (.Lfs0, .Lfe0) LC0 = P0; +.Lfs0: R6 = R5 << 5; /* Combine set*/ + R6.H = R3.H << 0 ; /* and sub-bank*/ + R6 = R6 | R2; /* and Bank. Leave Way==0 at first.*/ + BITSET(R6,14); + [P5] = R6; /* Issue Command*/ + SSYNC; + R7 = [P4]; /* and read Tag.*/ + CC = BITTST(R7, 0); /* Check if valid*/ + IF !CC JUMP .Lfskip; /* and skip if not.*/ + CC = BITTST(R7, 1); /* Check if dirty*/ + IF !CC JUMP .Lfskip; /* and skip if not.*/ + + /* Compare against the page address. First, plant bits 13:12 + * into the tag, since those aren't part of the returned data. + */ + + R7 = DEPOSIT(R7, R3); /* set 13:12*/ + R1 = R7 & R4; /* Mask off lower bits*/ + CC = R1 == R0; /* Compare against page start.*/ + IF !CC JUMP .Lfskip; /* Skip it if it doesn't match.*/ + + /* Tag address matches against page, so this is an entry + * we must flush. + */ + + R7 >>= 10; /* Mask off the non-address bits*/ + R7 <<= 10; + P3 = R7; + SSYNC; + FLUSHINV [P3]; /* And flush the entry*/ +.Lfskip: +.Lfe0: R5 += 1; /* Advance to next Set*/ +.Lfe1: BITSET(R2, 26); /* Go to next Way.*/ + +.Ldfinished: + SSYNC; /* Ensure the data gets out to mem.*/ + + /*Finished. Restore context.*/ + LB1 = [SP++]; + LT1 = [SP++]; + LC1 = [SP++]; + LB0 = [SP++]; + LT0 = [SP++]; + LC0 = [SP++]; + ( R7:0, P5:0 ) = [SP++]; + RTS; + +.Ldflush_whole_page: + + /* It's a 1K or 4K page, so quicker to just flush the + * entire page. + */ + + P1 = 32; /* For 1K pages*/ + P2 = P1 << 2; /* For 4K pages*/ + P0 = R0; /* Start of page*/ + CC = BITTST(R1, 16); /* Whether 1K or 4K*/ + IF CC P1 = P2; + P1 += -1; /* Unroll one iteration*/ + SSYNC; + FLUSHINV [P0++]; /* because CSYNC can't end loops.*/ + LSETUP (.Leall, .Leall) LC0 = P1; +.Leall: FLUSHINV [P0++]; + SSYNC; + JUMP .Ldfinished; +ENDPROC(_dcplb_flush) + +.align 4; +page_prefix_table: +.byte4 0xFFFFFC00; /* 1K */ +.byte4 0xFFFFF000; /* 4K */ +.byte4 0xFFF00000; /* 1M */ +.byte4 0xFFC00000; /* 4M */ +.page_prefix_table.end: |