[PATCH 2/6] ARM: add generic PrimeCell interface to COH 901 318
Linus Walleij
linus.walleij at stericsson.com
Mon Mar 29 19:36:04 EDT 2010
This extends the DMA engine driver for the COH 901 318 used in the
U300 platform with the generic PrimeCell interface,
Signed-off-by: Linus Walleij <linus.walleij at stericsson.com>
---
drivers/dma/coh901318.c | 146 +++++++++++++++++++++++++++++++++++++++++++
drivers/dma/coh901318_lli.c | 78 ++++++++++++++++++++++-
2 files changed, 221 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index 4233440..1d5ed16 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -21,6 +21,7 @@
#include <linux/uaccess.h>
#include <linux/debugfs.h>
#include <mach/coh901318.h>
+#include <linux/amba/dma.h>
#include "coh901318_lli.h"
@@ -72,6 +73,9 @@ struct coh901318_chan {
unsigned long nbr_active_done;
unsigned long busy;
+ u32 amba_addr;
+ u32 amba_ctrl;
+
struct coh901318_base *base;
};
@@ -190,6 +194,9 @@ static inline struct coh901318_chan *to_coh901318_chan(struct dma_chan *chan)
static inline dma_addr_t
cohc_dev_addr(struct coh901318_chan *cohc)
{
+ /* PrimeCell supplied address will take precedence */
+ if (cohc->amba_addr)
+ return cohc->amba_addr;
return cohc->base->platform->chan_conf[cohc->id].dev_addr;
}
@@ -1055,6 +1062,14 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
params = cohc_chan_param(cohc);
config = params->config;
+ /*
+ * Add primecell-specific control on top, make
+ * sure the bits you set per peripheral channel are
+ * cleared in the default config from the platform.
+ */
+ ctrl_chained |= cohc->amba_ctrl;
+ ctrl_last |= cohc->amba_ctrl;
+ ctrl |= cohc->amba_ctrl;
if (direction == DMA_TO_DEVICE) {
u32 tx_flags = COH901318_CX_CTRL_PRDD_SOURCE |
@@ -1113,6 +1128,12 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
if (ret)
goto err_lli_fill;
+ /*
+ * Set the default ctrl for the channel to the one from the lli,
+ * things may have changed due to odd buffer alignment etc.
+ */
+ coh901318_set_ctrl(cohc, lli->control);
+
COH_DBG(coh901318_list_print(cohc, lli));
/* Pick a descriptor to handle this transfer */
@@ -1239,6 +1260,131 @@ coh901318_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd)
return 0;
}
+
+/*
+ * Here we wrap in the PrimeCell dma interface
+ */
+struct burst_table {
+ int burst_8bit;
+ int burst_16bit;
+ int burst_32bit;
+ u32 reg;
+};
+
+static const struct burst_table burst_sizes[] = {
+ {
+ .burst_8bit = 64,
+ .burst_16bit = 32,
+ .burst_32bit = 16,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_64_BYTES,
+ },
+ {
+ .burst_8bit = 48,
+ .burst_16bit = 24,
+ .burst_32bit = 12,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_48_BYTES,
+ },
+ {
+ .burst_8bit = 32,
+ .burst_16bit = 16,
+ .burst_32bit = 8,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_32_BYTES,
+ },
+ {
+ .burst_8bit = 16,
+ .burst_16bit = 8,
+ .burst_32bit = 4,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_16_BYTES,
+ },
+ {
+ .burst_8bit = 8,
+ .burst_16bit = 4,
+ .burst_32bit = 2,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_8_BYTES,
+ },
+ {
+ .burst_8bit = 4,
+ .burst_16bit = 2,
+ .burst_32bit = 1,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_4_BYTES,
+ },
+ {
+ .burst_8bit = 2,
+ .burst_16bit = 1,
+ .burst_32bit = 0,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_2_BYTES,
+ },
+ {
+ .burst_8bit = 1,
+ .burst_16bit = 0,
+ .burst_32bit = 0,
+ .reg = COH901318_CX_CTRL_BURST_COUNT_1_BYTE,
+ },
+};
+
+void dma_set_ambaconfig(struct dma_chan *chan,
+ struct amba_dma_channel_config *config)
+{
+ struct coh901318_chan *cohc = to_coh901318_chan(chan);
+ int maxburst = config->maxburst;
+ u32 amba_ctrl = 0;
+ int i = 0;
+
+ dev_dbg(COHC_2_DEV(cohc), "configure channel for %d byte transfers\n",
+ config->addr_width);
+ switch (config->addr_width) {
+ case 1:
+ amba_ctrl |=
+ COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS |
+ COH901318_CX_CTRL_DST_BUS_SIZE_8_BITS;
+
+ while (i < ARRAY_SIZE(burst_sizes)) {
+ if (burst_sizes[i].burst_8bit <= maxburst)
+ break;
+ i++;
+ }
+
+ break;
+ case 2:
+ amba_ctrl |=
+ COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS |
+ COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
+
+ while (i < ARRAY_SIZE(burst_sizes)) {
+ if (burst_sizes[i].burst_16bit <= maxburst)
+ break;
+ i++;
+ }
+
+ break;
+ case 4:
+ /* Direction doesn't matter here, it's 32/32 bits */
+ amba_ctrl |=
+ COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS |
+ COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
+
+ while (i < ARRAY_SIZE(burst_sizes)) {
+ if (burst_sizes[i].burst_32bit <= maxburst)
+ break;
+ i++;
+ }
+
+ break;
+ default:
+ dev_err(COHC_2_DEV(cohc),
+ "bad ambaconfig: alien address width\n");
+ return;
+ }
+
+ amba_ctrl |= burst_sizes[i].reg;
+ dev_dbg(COHC_2_DEV(cohc),
+ "selected burst size %d bytes for address width %d bytes, maxburst %d\n",
+ burst_sizes[i].burst_8bit, config->addr_width, maxburst);
+
+ cohc->amba_addr = config->addr;
+ cohc->amba_ctrl = amba_ctrl;
+}
+
void coh901318_base_init(struct dma_device *dma, const int *pick_chans,
struct coh901318_base *base)
{
diff --git a/drivers/dma/coh901318_lli.c b/drivers/dma/coh901318_lli.c
index 9f7e0e6..f37db49 100644
--- a/drivers/dma/coh901318_lli.c
+++ b/drivers/dma/coh901318_lli.c
@@ -153,6 +153,39 @@ coh901318_lli_fill_memcpy(struct coh901318_pool *pool,
lli->src_addr = src;
lli->dst_addr = dst;
+ /*
+ * The DMA hardware will increase its pointer by 1,
+ * 2 or 4 bytes at a time depending on configuration.
+ * If using som oddly-aligned buffer this will cause
+ * performance problems.
+ */
+#if 0
+ ctrl_chained &= ~COH901318_CX_CTRL_SRC_BUS_SIZE_MASK;
+ ctrl_eom &= ~COH901318_CX_CTRL_SRC_BUS_SIZE_MASK;
+ ctrl_chained &= ~COH901318_CX_CTRL_DST_BUS_SIZE_MASK;
+ ctrl_eom &= ~COH901318_CX_CTRL_DST_BUS_SIZE_MASK;
+ if (src & 0x01) {
+ ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS;
+ ctrl_eom |= COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS;
+ } else if (src & 0x02) {
+ ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS;
+ ctrl_eom |= COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS;
+ } else {
+ ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS;
+ ctrl_eom |= COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS;
+ }
+ if (dst & 0x01) {
+ ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_8_BITS;
+ ctrl_eom |= COH901318_CX_CTRL_SRC_DST_SIZE_8_BITS;
+ } else if (dst & 0x02) {
+ ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
+ ctrl_eom |= COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
+ } else {
+ ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
+ ctrl_eom |= COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
+ }
+#endif
+
while (lli->link_addr) {
lli->control = ctrl_chained | MAX_DMA_PACKET_SIZE;
lli->src_addr = src;
@@ -268,13 +301,52 @@ coh901318_lli_fill_sg(struct coh901318_pool *pool,
else
ctrl_sg = ctrl ? ctrl : ctrl_last;
-
- if (dir == DMA_TO_DEVICE)
+ /*
+ * If the physical address is only divisible by 1 or
+ * two, we have to lower the destination bus size to
+ * the least common denominator
+ */
+ if (dir == DMA_TO_DEVICE) {
/* increment source address */
src = sg_phys(sg);
- else
+#if 0
+ ctrl_sg &= ~COH901318_CX_CTRL_SRC_BUS_SIZE_MASK;
+ ctrl_chained &= ~COH901318_CX_CTRL_SRC_BUS_SIZE_MASK;
+ if (src & 0x01) {
+ pr_err("Aligned src buffer to 8bit access\n");
+ ctrl_sg |= COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS;
+ ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS;
+ } else if (src & 0x02) {
+ pr_err("Aligned src buffer to 16bit access\n");
+ ctrl_sg |= COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS;
+ ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS;
+ } else {
+ pr_err("Aligned src buffer to 32bit access\n");
+ ctrl_sg |= COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS;
+ ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS;
+ }
+#endif
+ } else {
/* increment destination address */
dst = sg_phys(sg);
+#if 0
+ ctrl_sg &= ~COH901318_CX_CTRL_DST_BUS_SIZE_MASK;
+ ctrl_chained &= ~COH901318_CX_CTRL_DST_BUS_SIZE_MASK;
+ if (dst & 0x01) {
+ pr_err("Aligned dst buffer to 8bit access\n");
+ ctrl_sg |= COH901318_CX_CTRL_DST_BUS_SIZE_8_BITS;
+ ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_8_BITS;
+ } else if (dst & 0x02) {
+ pr_err("Aligned dst buffer to 16bit access\n");
+ ctrl_sg |= COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
+ ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
+ } else {
+ pr_err("Aligned dst buffer to 32bit access\n");
+ ctrl_sg |= COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
+ ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
+ }
+#endif
+ }
bytes_to_transfer = sg_dma_len(sg);
--
1.6.3.3
More information about the linux-arm-kernel
mailing list