From db9f136a60c8727c8e1c9c4f2494821caebf5a7b Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Mon, 3 Jan 2011 22:38:32 +0000 Subject: [PATCH] ARM: PL08x: clean up LLI lookup As the LLI list is an array, we can use maths to locate which LLI index we're currently at, and then sum up the remaining LLI entries until we reach the end of the list. This makes the code much easier to read, and much less susceptible to falling off the end of the array. Signed-off-by: Russell King Acked-by: Linus Walleij Signed-off-by: Dan Williams --- drivers/dma/amba-pl08x.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c index a897315..202c9e2 100644 --- a/drivers/dma/amba-pl08x.c +++ b/drivers/dma/amba-pl08x.c @@ -340,53 +340,56 @@ static inline u32 get_bytes_in_cctl(u32 cctl) static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan) { struct pl08x_phy_chan *ch; - struct pl08x_txd *txdi = NULL; struct pl08x_txd *txd; unsigned long flags; size_t bytes = 0; spin_lock_irqsave(&plchan->lock, flags); - ch = plchan->phychan; txd = plchan->at; /* - * Next follow the LLIs to get the number of pending bytes in the - * currently active transaction. + * Follow the LLIs to get the number of remaining + * bytes in the currently active transaction. */ if (ch && txd) { - struct pl08x_lli *llis_va = txd->llis_va; - struct pl08x_lli *llis_bus = (struct pl08x_lli *) txd->llis_bus; u32 clli = readl(ch->base + PL080_CH_LLI) & ~PL080_LLI_LM_AHB2; - /* First get the bytes in the current active LLI */ + /* First get the remaining bytes in the active transfer */ bytes = get_bytes_in_cctl(readl(ch->base + PL080_CH_CONTROL)); if (clli) { - int i = 0; + struct pl08x_lli *llis_va = txd->llis_va; + dma_addr_t llis_bus = txd->llis_bus; + int index; - /* Forward to the LLI pointed to by clli */ - while ((clli != (u32) &(llis_bus[i])) && - (i < MAX_NUM_TSFR_LLIS)) - i++; + BUG_ON(clli < llis_bus || clli >= llis_bus + + sizeof(struct pl08x_lli) * MAX_NUM_TSFR_LLIS); + + /* + * Locate the next LLI - as this is an array, + * it's simple maths to find. + */ + index = (clli - llis_bus) / sizeof(struct pl08x_lli); + + for (; index < MAX_NUM_TSFR_LLIS; index++) { + bytes += get_bytes_in_cctl(llis_va[index].cctl); - while (clli) { - bytes += get_bytes_in_cctl(llis_va[i].cctl); /* * A LLI pointer of 0 terminates the LLI list */ - clli = llis_va[i].lli; - i++; + if (!llis_va[index].lli) + break; } } } /* Sum up all queued transactions */ if (!list_empty(&plchan->desc_list)) { + struct pl08x_txd *txdi; list_for_each_entry(txdi, &plchan->desc_list, node) { bytes += txdi->len; } - } spin_unlock_irqrestore(&plchan->lock, flags); -- 2.7.4