From 511cdcc50031eacd88cc70351da54beebff515e2 Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Thu, 3 Feb 2011 02:16:44 +0000 Subject: [PATCH] Blackfin: optimize startup code Take advantage of more Blackfin-specific insns, and only initialize registers required by the ABI. Signed-off-by: Mike Frysinger --- arch/blackfin/mach-common/head.S | 110 ++++++++++++------------------- 1 file changed, 41 insertions(+), 69 deletions(-) diff --git a/arch/blackfin/mach-common/head.S b/arch/blackfin/mach-common/head.S index 4391621d904..581e2b0a71a 100644 --- a/arch/blackfin/mach-common/head.S +++ b/arch/blackfin/mach-common/head.S @@ -31,6 +31,7 @@ ENDPROC(__init_clear_bss) ENTRY(__start) /* R0: argument of command line string, passed from uboot, save it */ R7 = R0; + /* Enable Cycle Counter and Nesting Of Interrupts */ #ifdef CONFIG_BFIN_SCRATCH_REG_CYCLES R0 = SYSCFG_SNEN; @@ -38,76 +39,49 @@ ENTRY(__start) R0 = SYSCFG_SNEN | SYSCFG_CCEN; #endif SYSCFG = R0; - R0 = 0; - - /* Clear Out All the data and pointer Registers */ - R1 = R0; - R2 = R0; - R3 = R0; - R4 = R0; - R5 = R0; - R6 = R0; - - P0 = R0; - P1 = R0; - P2 = R0; - P3 = R0; - P4 = R0; - P5 = R0; - - LC0 = r0; - LC1 = r0; - L0 = r0; - L1 = r0; - L2 = r0; - L3 = r0; - - /* Clear Out All the DAG Registers */ - B0 = r0; - B1 = r0; - B2 = r0; - B3 = r0; - - I0 = r0; - I1 = r0; - I2 = r0; - I3 = r0; - - M0 = r0; - M1 = r0; - M2 = r0; - M3 = r0; + + /* Optimization register tricks: keep a base value in the + * reserved P registers so we use the load/store with an + * offset syntax. R0 = [P5 + ]; + * P5 - core MMR base + * R6 - 0 + */ + r6 = 0; + p5.l = 0; + p5.h = hi(COREMMR_BASE); + + /* Zero out registers required by Blackfin ABI */ + + /* Disable circular buffers */ + L0 = r6; + L1 = r6; + L2 = r6; + L3 = r6; + + /* Disable hardware loops in case we were started by 'go' */ + LC0 = r6; + LC1 = r6; /* * Clear ITEST_COMMAND and DTEST_COMMAND registers, * Leaving these as non-zero can confuse the emulator */ - p0.L = LO(DTEST_COMMAND); - p0.H = HI(DTEST_COMMAND); - [p0] = R0; - [p0 + (ITEST_COMMAND - DTEST_COMMAND)] = R0; + [p5 + (DTEST_COMMAND - COREMMR_BASE)] = r6; + [p5 + (ITEST_COMMAND - COREMMR_BASE)] = r6; CSYNC; trace_buffer_init(p0,r0); - P0 = R1; - R0 = R1; /* Turn off the icache */ - p0.l = LO(IMEM_CONTROL); - p0.h = HI(IMEM_CONTROL); - R1 = [p0]; - R0 = ~ENICPLB; - R0 = R0 & R1; - [p0] = R0; + r1 = [p5 + (IMEM_CONTROL - COREMMR_BASE)]; + BITCLR (r1, ENICPLB_P); + [p5 + (IMEM_CONTROL - COREMMR_BASE)] = r1; SSYNC; /* Turn off the dcache */ - p0.l = LO(DMEM_CONTROL); - p0.h = HI(DMEM_CONTROL); - R1 = [p0]; - R0 = ~ENDCPLB; - R0 = R0 & R1; - [p0] = R0; + r1 = [p5 + (DMEM_CONTROL - COREMMR_BASE)]; + BITCLR (r1, ENDCPLB_P); + [p5 + (DMEM_CONTROL - COREMMR_BASE)] = r1; SSYNC; /* in case of double faults, save a few things */ @@ -122,25 +96,25 @@ ENTRY(__start) * below */ GET_PDA(p0, r0); - r6 = [p0 + PDA_DF_RETX]; + r5 = [p0 + PDA_DF_RETX]; p1.l = _init_saved_retx; p1.h = _init_saved_retx; - [p1] = r6; + [p1] = r5; - r6 = [p0 + PDA_DF_DCPLB]; + r5 = [p0 + PDA_DF_DCPLB]; p1.l = _init_saved_dcplb_fault_addr; p1.h = _init_saved_dcplb_fault_addr; - [p1] = r6; + [p1] = r5; - r6 = [p0 + PDA_DF_ICPLB]; + r5 = [p0 + PDA_DF_ICPLB]; p1.l = _init_saved_icplb_fault_addr; p1.h = _init_saved_icplb_fault_addr; - [p1] = r6; + [p1] = r5; - r6 = [p0 + PDA_DF_SEQSTAT]; + r5 = [p0 + PDA_DF_SEQSTAT]; p1.l = _init_saved_seqstat; p1.h = _init_saved_seqstat; - [p1] = r6; + [p1] = r5; #endif /* Initialize stack pointer */ @@ -155,7 +129,7 @@ ENTRY(__start) sti r0; #endif - r0 = 0 (x); + r0 = r6; /* Zero out all of the fun bss regions */ #if L1_DATA_A_LENGTH > 0 r1.l = __sbss_l1; @@ -210,11 +184,9 @@ ENTRY(__start) /* EVT15 = _real_start */ - p0.l = lo(EVT15); - p0.h = hi(EVT15); p1.l = _real_start; p1.h = _real_start; - [p0] = p1; + [p5 + (EVT15 - COREMMR_BASE)] = p1; csync; #ifdef CONFIG_EARLY_PRINTK -- 2.43.2