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Commit aaab5e83 authored by Grant Likely's avatar Grant Likely
Browse files

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: default avatarGrant Likely <grant.likely@secretlab.ca>
parent e4efe3c2

arch/powerpc/sysdev/bestcomm/ata.c

+3 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/sysdev/bestcomm/bestcomm.c

+2 −5
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/sysdev/bestcomm/bestcomm_priv.h

+16 −0
Original line number Diff line number Diff line
@@ -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)

{