diff options
| author | Grant Likely <grant.likely@secretlab.ca> | 2008-12-21 02:54:28 -0700 |
|---|---|---|
| committer | Grant Likely <grant.likely@secretlab.ca> | 2008-12-21 02:54:28 -0700 |
| commit | aaab5e83c2c25d94f7409bdc947a5cc383514e15 (patch) | |
| tree | 929571b5bf2728ac8494b56d0c4965b2aaa47da8 | |
| parent | e4efe3c271c5498ffe7e167eaff01514be2b9a77 (diff) | |
powerpc/mpc5200: Disable bestcomm prefetching when ATA DMA enabled
When ATA DMA is enabled, bestcomm prefetching does not work. This
patch adds a function to disable bestcomm prefetch when the ATA
Bestcomm task is initialized.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
| -rw-r--r-- | arch/powerpc/sysdev/bestcomm/ata.c | 3 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/bestcomm/bestcomm.c | 7 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/bestcomm/bestcomm_priv.h | 16 |
3 files changed, 21 insertions, 5 deletions
diff --git a/arch/powerpc/sysdev/bestcomm/ata.c b/arch/powerpc/sysdev/bestcomm/ata.c index 1f5258fb38c..901c9f91e5d 100644 --- a/arch/powerpc/sysdev/bestcomm/ata.c +++ b/arch/powerpc/sysdev/bestcomm/ata.c @@ -61,6 +61,9 @@ bcom_ata_init(int queue_len, int maxbufsize) struct bcom_ata_var *var; struct bcom_ata_inc *inc; + /* Prefetch breaks ATA DMA. Turn it off for ATA DMA */ + bcom_disable_prefetch(); + tsk = bcom_task_alloc(queue_len, sizeof(struct bcom_ata_bd), 0); if (!tsk) return NULL; diff --git a/arch/powerpc/sysdev/bestcomm/bestcomm.c b/arch/powerpc/sysdev/bestcomm/bestcomm.c index 446c9ea85b3..378ebd9aac1 100644 --- a/arch/powerpc/sysdev/bestcomm/bestcomm.c +++ b/arch/powerpc/sysdev/bestcomm/bestcomm.c @@ -279,7 +279,6 @@ bcom_engine_init(void) int task; phys_addr_t tdt_pa, ctx_pa, var_pa, fdt_pa; unsigned int tdt_size, ctx_size, var_size, fdt_size; - u16 regval; /* Allocate & clear SRAM zones for FDT, TDTs, contexts and vars/incs */ tdt_size = BCOM_MAX_TASKS * sizeof(struct bcom_tdt); @@ -331,10 +330,8 @@ bcom_engine_init(void) out_8(&bcom_eng->regs->ipr[BCOM_INITIATOR_ALWAYS], BCOM_IPR_ALWAYS); /* Disable COMM Bus Prefetch on the original 5200; it's broken */ - if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR) { - regval = in_be16(&bcom_eng->regs->PtdCntrl); - out_be16(&bcom_eng->regs->PtdCntrl, regval | 1); - } + if ((mfspr(SPRN_SVR) & MPC5200_SVR_MASK) == MPC5200_SVR) + bcom_disable_prefetch(); /* Init lock */ spin_lock_init(&bcom_eng->lock); diff --git a/arch/powerpc/sysdev/bestcomm/bestcomm_priv.h b/arch/powerpc/sysdev/bestcomm/bestcomm_priv.h index 746f1551c8a..eb0d1c883c3 100644 --- a/arch/powerpc/sysdev/bestcomm/bestcomm_priv.h +++ b/arch/powerpc/sysdev/bestcomm/bestcomm_priv.h @@ -241,6 +241,22 @@ extern void bcom_set_initiator(int task, int initiator); #define TASK_ENABLE 0x8000 +/** + * bcom_disable_prefetch - Hook to disable bus prefetching + * + * ATA DMA and the original MPC5200 need this due to silicon bugs. At the + * moment disabling prefetch is a one-way street. There is no mechanism + * in place to turn prefetch back on after it has been disabled. There is + * no reason it couldn't be done, it would just be more complex to implement. + */ +static inline void bcom_disable_prefetch(void) +{ + u16 regval; + + regval = in_be16(&bcom_eng->regs->PtdCntrl); + out_be16(&bcom_eng->regs->PtdCntrl, regval | 1); +}; + static inline void bcom_enable_task(int task) { |