From 955b17665d2c221521c554ae6aa22c2486de1a27 Mon Sep 17 00:00:00 2001 From: Amelie Delaunay Date: Wed, 22 Apr 2020 12:29:04 +0200 Subject: [PATCH] dmaengine: stm32-dma: direct mode support through device tree Direct mode or FIFO mode is computed by stm32-dma driver. Add a way for the user to force direct mode, by setting bit 2 in the bitfield value specifying DMA features in the device tree. Signed-off-by: Amelie Delaunay Link: https://lore.kernel.org/r/20200422102904.1448-3-amelie.delaunay@st.com Signed-off-by: Vinod Koul --- drivers/dma/stm32-dma.c | 41 +++++++++++++++++++++++++++++++---------- 1 file changed, 31 insertions(+), 10 deletions(-) diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index 0ddbaa4..96ad1b3 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -117,6 +117,7 @@ #define STM32_DMA_FIFO_THRESHOLD_HALFFULL 0x01 #define STM32_DMA_FIFO_THRESHOLD_3QUARTERSFULL 0x02 #define STM32_DMA_FIFO_THRESHOLD_FULL 0x03 +#define STM32_DMA_FIFO_THRESHOLD_NONE 0x04 #define STM32_DMA_MAX_DATA_ITEMS 0xffff /* @@ -136,6 +137,9 @@ /* DMA Features */ #define STM32_DMA_THRESHOLD_FTR_MASK GENMASK(1, 0) #define STM32_DMA_THRESHOLD_FTR_GET(n) ((n) & STM32_DMA_THRESHOLD_FTR_MASK) +#define STM32_DMA_DIRECT_MODE_MASK BIT(2) +#define STM32_DMA_DIRECT_MODE_GET(n) (((n) & STM32_DMA_DIRECT_MODE_MASK) \ + >> 2) enum stm32_dma_width { STM32_DMA_BYTE, @@ -281,6 +285,9 @@ static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold, { u32 remaining; + if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE) + return false; + if (width != DMA_SLAVE_BUSWIDTH_UNDEFINED) { if (burst != 0) { /* @@ -302,6 +309,10 @@ static bool stm32_dma_fifo_threshold_is_allowed(u32 burst, u32 threshold, static bool stm32_dma_is_burst_possible(u32 buf_len, u32 threshold) { + /* If FIFO direct mode, burst is not possible */ + if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE) + return false; + /* * Buffer or period length has to be aligned on FIFO depth. * Otherwise bytes may be stuck within FIFO at buffer or period @@ -657,6 +668,12 @@ static irqreturn_t stm32_dma_chan_irq(int irq, void *devid) dev_dbg(chan2dev(chan), "FIFO over/underrun\n"); } } + if (status & STM32_DMA_DMEI) { + stm32_dma_irq_clear(chan, STM32_DMA_DMEI); + status &= ~STM32_DMA_DMEI; + if (sfcr & STM32_DMA_SCR_DMEIE) + dev_dbg(chan2dev(chan), "Direct mode overrun\n"); + } if (status) { stm32_dma_irq_clear(chan, status); dev_err(chan2dev(chan), "DMA error: status=0x%08x\n", status); @@ -692,13 +709,13 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, int src_bus_width, dst_bus_width; int src_burst_size, dst_burst_size; u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst; - u32 dma_scr, threshold; + u32 dma_scr, fifoth; src_addr_width = chan->dma_sconfig.src_addr_width; dst_addr_width = chan->dma_sconfig.dst_addr_width; src_maxburst = chan->dma_sconfig.src_maxburst; dst_maxburst = chan->dma_sconfig.dst_maxburst; - threshold = chan->threshold; + fifoth = chan->threshold; switch (direction) { case DMA_MEM_TO_DEV: @@ -710,7 +727,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, /* Set device burst size */ dst_best_burst = stm32_dma_get_best_burst(buf_len, dst_maxburst, - threshold, + fifoth, dst_addr_width); dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst); @@ -718,7 +735,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, return dst_burst_size; /* Set memory data size */ - src_addr_width = stm32_dma_get_max_width(buf_len, threshold); + src_addr_width = stm32_dma_get_max_width(buf_len, fifoth); chan->mem_width = src_addr_width; src_bus_width = stm32_dma_get_width(chan, src_addr_width); if (src_bus_width < 0) @@ -728,7 +745,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, src_maxburst = STM32_DMA_MAX_BURST; src_best_burst = stm32_dma_get_best_burst(buf_len, src_maxburst, - threshold, + fifoth, src_addr_width); src_burst_size = stm32_dma_get_burst(chan, src_best_burst); if (src_burst_size < 0) @@ -742,7 +759,8 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, /* Set FIFO threshold */ chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK; - chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold); + if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE) + chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(fifoth); /* Set peripheral address */ chan->chan_reg.dma_spar = chan->dma_sconfig.dst_addr; @@ -758,7 +776,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, /* Set device burst size */ src_best_burst = stm32_dma_get_best_burst(buf_len, src_maxburst, - threshold, + fifoth, src_addr_width); chan->mem_burst = src_best_burst; src_burst_size = stm32_dma_get_burst(chan, src_best_burst); @@ -766,7 +784,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, return src_burst_size; /* Set memory data size */ - dst_addr_width = stm32_dma_get_max_width(buf_len, threshold); + dst_addr_width = stm32_dma_get_max_width(buf_len, fifoth); chan->mem_width = dst_addr_width; dst_bus_width = stm32_dma_get_width(chan, dst_addr_width); if (dst_bus_width < 0) @@ -776,7 +794,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, dst_maxburst = STM32_DMA_MAX_BURST; dst_best_burst = stm32_dma_get_best_burst(buf_len, dst_maxburst, - threshold, + fifoth, dst_addr_width); chan->mem_burst = dst_best_burst; dst_burst_size = stm32_dma_get_burst(chan, dst_best_burst); @@ -791,7 +809,8 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan, /* Set FIFO threshold */ chan->chan_reg.dma_sfcr &= ~STM32_DMA_SFCR_FTH_MASK; - chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(threshold); + if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE) + chan->chan_reg.dma_sfcr |= STM32_DMA_SFCR_FTH(fifoth); /* Set peripheral address */ chan->chan_reg.dma_spar = chan->dma_sconfig.src_addr; @@ -1216,6 +1235,8 @@ static void stm32_dma_set_config(struct stm32_dma_chan *chan, chan->chan_reg.dma_scr |= STM32_DMA_SCR_TEIE | STM32_DMA_SCR_TCIE; chan->threshold = STM32_DMA_THRESHOLD_FTR_GET(cfg->features); + if (STM32_DMA_DIRECT_MODE_GET(cfg->features)) + chan->threshold = STM32_DMA_FIFO_THRESHOLD_NONE; } static struct dma_chan *stm32_dma_of_xlate(struct of_phandle_args *dma_spec, -- 2.7.4