From f5d79afa3a858eb6e5cf2bcd894ed53b5bd8b5ff Mon Sep 17 00:00:00 2001 From: Tudor Ambarus Date: Tue, 25 Oct 2022 12:02:53 +0300 Subject: dmaengine: at_hdmac: Pass residue by address to avoid unnecessary implicit casts struct dma_tx_state defines residue as u32. atc_get_bytes_left() returned an int which could be either an error or the value of the residue. This could cause problems if the controller supported a u32 buffer transfer size and the u32 value was past the max int can hold. Our controller does not support u32 buffer transfer size, but even so, improve the code and pass the residue by address to avoid unnecessary implicit casts and make atc_get_bytes_left() return 0 on success or -errno on errors. Signed-off-by: Tudor Ambarus Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-20-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul --- drivers/dma/at_hdmac.c | 54 ++++++++++++++++++++++++++++---------------------- 1 file changed, 30 insertions(+), 24 deletions(-) (limited to 'drivers/dma') diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index fbfb207104e9..e2c46f32b284 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -293,7 +293,7 @@ static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan, * @current_len: the number of bytes left before reading CTRLA * @ctrla: the value of CTRLA */ -static inline int atc_calc_bytes_left(int current_len, u32 ctrla) +static inline u32 atc_calc_bytes_left(u32 current_len, u32 ctrla) { u32 btsize = (ctrla & ATC_BTSIZE_MAX); u32 src_width = ATC_REG_TO_SRC_WIDTH(ctrla); @@ -308,17 +308,20 @@ static inline int atc_calc_bytes_left(int current_len, u32 ctrla) } /** - * atc_get_bytes_left - get the number of bytes residue for a cookie + * atc_get_bytes_left - get the number of bytes residue for a cookie. + * The residue is passed by address and updated on success. * @chan: DMA channel * @cookie: transaction identifier to check status of + * @residue: residue to be updated. + * Return 0 on success, -errono otherwise. */ -static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) +static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie, + u32 *residue) { struct at_dma_chan *atchan = to_at_dma_chan(chan); struct at_desc *desc_first = atc_first_active(atchan); struct at_desc *desc; - int ret; - u32 ctrla, dscr; + u32 len, ctrla, dscr; unsigned int i; /* @@ -333,7 +336,7 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) return desc->total_len; /* cookie matches to the currently running transfer */ - ret = desc_first->total_len; + len = desc_first->total_len; if (desc_first->lli.dscr) { /* hardware linked list transfer */ @@ -419,29 +422,31 @@ static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) return -ETIMEDOUT; /* for the first descriptor we can be more accurate */ - if (desc_first->lli.dscr == dscr) - return atc_calc_bytes_left(ret, ctrla); + if (desc_first->lli.dscr == dscr) { + *residue = atc_calc_bytes_left(len, ctrla); + return 0; + } - ret -= desc_first->len; + len -= desc_first->len; list_for_each_entry(desc, &desc_first->tx_list, desc_node) { if (desc->lli.dscr == dscr) break; - ret -= desc->len; + len -= desc->len; } /* * For the current descriptor in the chain we can calculate * the remaining bytes using the channel's register. */ - ret = atc_calc_bytes_left(ret, ctrla); + *residue = atc_calc_bytes_left(len, ctrla); } else { /* single transfer */ ctrla = channel_readl(atchan, CTRLA); - ret = atc_calc_bytes_left(ret, ctrla); + *residue = atc_calc_bytes_left(len, ctrla); } - return ret; + return 0; } /** @@ -1457,31 +1462,32 @@ atc_tx_status(struct dma_chan *chan, { struct at_dma_chan *atchan = to_at_dma_chan(chan); unsigned long flags; - enum dma_status ret; - int bytes = 0; + enum dma_status dma_status; + u32 residue; + int ret; - ret = dma_cookie_status(chan, cookie, txstate); - if (ret == DMA_COMPLETE || !txstate) - return ret; + dma_status = dma_cookie_status(chan, cookie, txstate); + if (dma_status == DMA_COMPLETE || !txstate) + return dma_status; spin_lock_irqsave(&atchan->lock, flags); /* Get number of bytes left in the active transactions */ - bytes = atc_get_bytes_left(chan, cookie); + ret = atc_get_bytes_left(chan, cookie, &residue); spin_unlock_irqrestore(&atchan->lock, flags); - if (unlikely(bytes < 0)) { + if (unlikely(ret < 0)) { dev_vdbg(chan2dev(chan), "get residual bytes error\n"); return DMA_ERROR; } else { - dma_set_residue(txstate, bytes); + dma_set_residue(txstate, residue); } - dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %d\n", - ret, cookie, bytes); + dev_vdbg(chan2dev(chan), "tx_status %d: cookie = %d residue = %u\n", + dma_status, cookie, residue); - return ret; + return dma_status; } /** -- cgit v1.2.3