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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>
This commit is contained in:
Grant Likely 2008-12-21 02:54:28 -07:00
parent e4efe3c271
commit aaab5e83c2
3 changed files with 21 additions and 5 deletions
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3
arch/powerpc/sysdev/bestcomm/ata.c
View File

@ -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;

7
arch/powerpc/sysdev/bestcomm/bestcomm.c
View File

@ -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);

16
arch/powerpc/sysdev/bestcomm/bestcomm_priv.h
View File

@ -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)
{