Blackfin arch: Faster C implementation of no-MPU CPLB handler

This is a mixture ofcMichael McTernan's patch and the existing cplb-mpu code.

We ditch the old cplb-nompu implementation, which is a good example of
why a good algorithm in a HLL is preferrable to a bad algorithm written in
assembly.  Rather than try to construct a table of all posible CPLBs and
search it, we just create a (smaller) table of memory regions and
their attributes.  Some of the data structures are now unified for both
the mpu and nompu cases.  A lot of needless complexity in cplbinit.c is
removed.

Further optimizations:
  * compile cplbmgr.c with a lot of -ffixed-reg options, and omit saving
    these registers on the stack when entering a CPLB exception.
  * lose cli/nop/nop/sti sequences for some workarounds - these don't
  * make
    sense in an exception context

Additional code unification should be possible after this.

[Mike Frysinger <vapier.adi@gmail.com>:
 - convert CPP if statements to C if statements
 - remove redundant statements
 - use a do...while loop rather than a for loop to get slightly better
   optimization and to avoid gcc "may be used uninitialized" warnings ...
   we know that the [id]cplb_nr_bounds variables will never be 0, so this
   is OK
 - the no-mpu code was the last user of MAX_MEM_SIZE and with that rewritten,
   we can punt it
 - add some BUG_ON() checks to make sure we dont overflow the small
   cplb_bounds array
 - add i/d cplb entries for the bootrom because there is functions/data in
   there we want to access
 - we do not need a NULL trailing entry as any time we access the bounds
   arrays, we use the nr_bounds variable
]

Signed-off-by: Michael McTernan <mmcternan@airvana.com>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

5 files changed, 79 insertions, 136 deletions

diff --git a/arch/blackfin/include/asm/context.S b/arch/blackfin/include/asm/context.S
index 9ce21f68e914..16561ab18b38 100644
--- a/arch/blackfin/include/asm/context.S
+++ b/arch/blackfin/include/asm/context.S
@@ -357,3 +357,42 @@
         SYSCFG = [sp++];
         csync;
 .endm
+
+.macro save_context_cplb
+        [--sp] = (R7:0, P5:0);
+        [--sp] = fp;
+
+        [--sp] = a0.x;
+        [--sp] = a0.w;
+        [--sp] = a1.x;
+        [--sp] = a1.w;
+
+        [--sp] = LC0;
+        [--sp] = LC1;
+        [--sp] = LT0;
+        [--sp] = LT1;
+        [--sp] = LB0;
+        [--sp] = LB1;
+
+        [--sp] = RETS;
+.endm
+
+.macro restore_context_cplb
+        RETS = [sp++];
+
+        LB1 = [sp++];
+        LB0 = [sp++];
+        LT1 = [sp++];
+        LT0 = [sp++];
+        LC1 = [sp++];
+        LC0 = [sp++];
+
+        a1.w = [sp++];
+        a1.x = [sp++];
+        a0.w = [sp++];
+        a0.x = [sp++];
+
+        fp = [sp++];
+
+        (R7:0, P5:0) = [SP++];
+.endm
diff --git a/arch/blackfin/include/asm/cplb-mpu.h b/arch/blackfin/include/asm/cplb-mpu.h
deleted file mode 100644
index 80680ad7a378..000000000000
--- a/arch/blackfin/include/asm/cplb-mpu.h
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * File:         include/asm-blackfin/cplbinit.h
- * Based on:
- * Author:
- *
- * Created:
- * Description:
- *
- * 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
- */
-#ifndef __ASM_BFIN_CPLB_MPU_H
-#define __ASM_BFIN_CPLB_MPU_H
-#include <linux/threads.h>
-
-struct cplb_entry {
-        unsigned long data, addr;
-};
-
-struct mem_region {
-        unsigned long start, end;
-        unsigned long dcplb_data;
-        unsigned long icplb_data;
-};
-
-extern struct cplb_entry dcplb_tbl[NR_CPUS][MAX_CPLBS];
-extern struct cplb_entry icplb_tbl[NR_CPUS][MAX_CPLBS];
-extern int first_switched_icplb;
-extern int first_mask_dcplb;
-extern int first_switched_dcplb;
-
-extern int nr_dcplb_miss[], nr_icplb_miss[], nr_icplb_supv_miss[];
-extern int nr_dcplb_prot[], nr_cplb_flush[];
-
-extern int page_mask_order;
-extern int page_mask_nelts;
-
-extern unsigned long *current_rwx_mask[NR_CPUS];
-
-extern void flush_switched_cplbs(unsigned int);
-extern void set_mask_dcplbs(unsigned long *, unsigned int);
-
-extern void __noreturn panic_cplb_error(int seqstat, struct pt_regs *);
-
-#endif /* __ASM_BFIN_CPLB_MPU_H */
diff --git a/arch/blackfin/include/asm/cplb.h b/arch/blackfin/include/asm/cplb.h
index 5f7545d06200..ad566ff9ad16 100644
--- a/arch/blackfin/include/asm/cplb.h
+++ b/arch/blackfin/include/asm/cplb.h
@@ -116,4 +116,8 @@
 #define CPLB_INOCACHE           CPLB_USER_RD | CPLB_VALID
 #define CPLB_IDOCACHE           CPLB_INOCACHE | CPLB_L1_CHBL
 
+#define FAULT_RW        (1 << 16)
+#define FAULT_USERSUPV  (1 << 17)
+#define FAULT_CPLBBITS  0x0000ffff
+
 #endif                          /* _CPLB_H */
diff --git a/arch/blackfin/include/asm/cplbinit.h b/arch/blackfin/include/asm/cplbinit.h
index 2aeec87d24e1..05b14a631d0c 100644
--- a/arch/blackfin/include/asm/cplbinit.h
+++ b/arch/blackfin/include/asm/cplbinit.h
@@ -32,96 +32,56 @@
 
 #include <asm/blackfin.h>
 #include <asm/cplb.h>
+#include <linux/threads.h>
 
-#ifdef CONFIG_MPU
-
-#include <asm/cplb-mpu.h>
-extern void bfin_icache_init(struct cplb_entry *icplb_tbl);
-extern void bfin_dcache_init(struct cplb_entry *icplb_tbl);
-
+#ifdef CONFIG_CPLB_SWITCH_TAB_L1
+# define PDT_ATTR __attribute__((l1_data))
 #else
+# define PDT_ATTR
+#endif
 
-#define INITIAL_T 0x1
-#define SWITCH_T  0x2
-#define I_CPLB    0x4
-#define D_CPLB    0x8
+struct cplb_entry {
+        unsigned long data, addr;
+};
 
-#define ASYNC_MEMORY_CPLB_COVERAGE  ((ASYNC_BANK0_SIZE + ASYNC_BANK1_SIZE + \
-                                ASYNC_BANK2_SIZE + ASYNC_BANK3_SIZE) / SIZE_4M)
+struct cplb_boundary {
+        unsigned long eaddr; /* End of this region.  */
+        unsigned long data; /* CPLB data value.  */
+};
 
-#define CPLB_MEM CONFIG_MAX_MEM_SIZE
+extern struct cplb_boundary dcplb_bounds[];
+extern struct cplb_boundary icplb_bounds[];
+extern int dcplb_nr_bounds, icplb_nr_bounds;
 
-/*
-* Number of required data CPLB switchtable entries
-* MEMSIZE / 4 (we mostly install 4M page size CPLBs
-* approx 16 for smaller 1MB page size CPLBs for allignment purposes
-* 1 for L1 Data Memory
-* possibly 1 for L2 Data Memory
-* 1 for CONFIG_DEBUG_HUNT_FOR_ZERO
-* 1 for ASYNC Memory
-*/
-#define MAX_SWITCH_D_CPLBS (((CPLB_MEM / 4) + 16 + 1 + 1 + 1 \
-                                 + ASYNC_MEMORY_CPLB_COVERAGE) * 2)
+extern struct cplb_entry dcplb_tbl[NR_CPUS][MAX_CPLBS];
+extern struct cplb_entry icplb_tbl[NR_CPUS][MAX_CPLBS];
+extern int first_switched_icplb;
+extern int first_switched_dcplb;
 
-/*
-* Number of required instruction CPLB switchtable entries
-* MEMSIZE / 4 (we mostly install 4M page size CPLBs
-* approx 12 for smaller 1MB page size CPLBs for allignment purposes
-* 1 for L1 Instruction Memory
-* possibly 1 for L2 Instruction Memory
-* 1 for CONFIG_DEBUG_HUNT_FOR_ZERO
-*/
-#define MAX_SWITCH_I_CPLBS (((CPLB_MEM / 4) + 12 + 1 + 1 + 1) * 2)
-
-/* Number of CPLB table entries, used for cplb-nompu. */
-#define CPLB_TBL_ENTRIES (16 * 4)
-
-enum {
-        ZERO_P, L1I_MEM, L1D_MEM, L2_MEM, SDRAM_KERN, SDRAM_RAM_MTD, SDRAM_DMAZ,
-        RES_MEM, ASYNC_MEM, OCB_ROM
-};
+extern int nr_dcplb_miss[], nr_icplb_miss[], nr_icplb_supv_miss[];
+extern int nr_dcplb_prot[], nr_cplb_flush[];
 
-struct cplb_desc {
-        u32 start; /* start address */
-        u32 end; /* end address */
-        u32 psize; /* prefered size if any otherwise 1MB or 4MB*/
-        u16 attr;/* attributes */
-        u16 i_conf;/* I-CPLB DATA */
-        u16 d_conf;/* D-CPLB DATA */
-        u16 valid;/* valid */
-        const s8 name[30];/* name */
-};
+#ifdef CONFIG_MPU
 
-struct cplb_tab {
-  u_long *tab;
-        u16 pos;
-        u16 size;
-};
+extern int first_mask_dcplb;
 
-extern u_long icplb_tables[NR_CPUS][CPLB_TBL_ENTRIES+1];
-extern u_long dcplb_tables[NR_CPUS][CPLB_TBL_ENTRIES+1];
+extern int page_mask_order;
+extern int page_mask_nelts;
 
-/* Till here we are discussing about the static memory management model.
- * However, the operating envoronments commonly define more CPLB
- * descriptors to cover the entire addressable memory than will fit into
- * the available on-chip 16 CPLB MMRs. When this happens, the below table
- * will be used which will hold all the potentially required CPLB descriptors
- *
- * This is how Page descriptor Table is implemented in uClinux/Blackfin.
- */
+extern unsigned long *current_rwx_mask[NR_CPUS];
 
-extern u_long ipdt_tables[NR_CPUS][MAX_SWITCH_I_CPLBS+1];
-extern u_long dpdt_tables[NR_CPUS][MAX_SWITCH_D_CPLBS+1];
-#ifdef CONFIG_CPLB_INFO
-extern u_long ipdt_swapcount_tables[NR_CPUS][MAX_SWITCH_I_CPLBS];
-extern u_long dpdt_swapcount_tables[NR_CPUS][MAX_SWITCH_D_CPLBS];
-#endif
-extern void bfin_icache_init(u_long icplbs[]);
-extern void bfin_dcache_init(u_long dcplbs[]);
+extern void flush_switched_cplbs(unsigned int);
+extern void set_mask_dcplbs(unsigned long *, unsigned int);
+
+extern void __noreturn panic_cplb_error(int seqstat, struct pt_regs *);
 
 #endif /* CONFIG_MPU */
 
+extern void bfin_icache_init(struct cplb_entry *icplb_tbl);
+extern void bfin_dcache_init(struct cplb_entry *icplb_tbl);
+
 #if defined(CONFIG_BFIN_DCACHE) || defined(CONFIG_BFIN_ICACHE)
+extern void generate_cplb_tables_all(void);
 extern void generate_cplb_tables_cpu(unsigned int cpu);
 #endif
 #endif
diff --git a/arch/blackfin/include/asm/entry.h b/arch/blackfin/include/asm/entry.h
index c4f721e0d00d..d94e4f5139d2 100644
--- a/arch/blackfin/include/asm/entry.h
+++ b/arch/blackfin/include/asm/entry.h
@@ -53,9 +53,11 @@
 /* This one pushes RETI without using CLI.  Interrupts are enabled.  */
 #define SAVE_CONTEXT_SYSCALL    save_context_syscall
 #define SAVE_CONTEXT            save_context_with_interrupts
+#define SAVE_CONTEXT_CPLB       save_context_cplb
 
 #define RESTORE_ALL_SYS         restore_context_no_interrupts
 #define RESTORE_CONTEXT         restore_context_with_interrupts
+#define RESTORE_CONTEXT_CPLB    restore_context_cplb
 
 #endif                          /* __ASSEMBLY__ */
 #endif                          /* __BFIN_ENTRY_H */