[PATCH 2/2 v4] dmaengine: mv_xor: Add support for IO (PCIe) src/dst areas
Stefan Roese
sr at denx.de
Thu Sep 1 02:39:04 PDT 2016
To enable the access to a specific area, the MVEBU XOR controllers needs
to have this area enabled / mapped via an address window. Right now,
only the DRAM memory area is enabled via such memory windows. So
using this driver to DMA to / from a e.g. PCIe memory region is
currently not supported.
This patch now adds support for such PCIe / IO regions by checking
if the src / dst address is located in an IO memory area in contrast
to being located in DRAM. This is done by using the newly introduced
MBus function mvebu_mbus_get_io_win_info(). If the src / dst address
is located in such an IO area, a new address window is created in
the XOR DMA controller. Enabling the controller to access this area.
Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Gregory CLEMENT <gregory.clement at free-electrons.com>
Cc: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Cc: Marcin Wojtas <mw at semihalf.com>
Cc: Arnd Bergmann <arnd at arndb.de>
Cc: Vinod Koul <vinod.koul at intel.com>
---
v3 -> v4:
- Don't try to add the IO windows on Armada 3700 which does not implement
the MBus driver
v2 -> v3:
- Included separate patch to add a stub function for mvebu_mbus_get_io_win_info()
to this patch series
- COMPILE_TEST added again, as the stub function now allows compilation on
all platforms
v1 -> v2:
- Removed COMPILE_TEST from Kconfig entry as this results in compilation
errors on non-Marvell platforms because of references to MBus driver
functions. Since this driver will never be used on non-Marvell platforms
this should be okay.
RFC -> v1:
- Use a cache for the already mapped areas for performance reasons, as
the MMIO registers don't need to get queried any more if the area is
already mapped now
drivers/dma/mv_xor.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++-
drivers/dma/mv_xor.h | 7 ++++
2 files changed, 101 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index f4c9f98..ff4a094 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -470,12 +470,90 @@ static int mv_xor_alloc_chan_resources(struct dma_chan *chan)
return mv_chan->slots_allocated ? : -ENOMEM;
}
+/*
+ * Check if source or destination is an PCIe/IO address (non-SDRAM) and add
+ * a new MBus window if necessary. Use a cache for these check so that
+ * the MMIO mapped registers don't have to be accessed for this check
+ * to speed up this process.
+ */
+static int mv_xor_add_io_win(struct mv_xor_chan *mv_chan, u32 addr)
+{
+ struct mv_xor_device *xordev = mv_chan->xordev;
+ void __iomem *base = mv_chan->mmr_high_base;
+ u32 win_enable;
+ u32 size;
+ u8 target, attr;
+ int ret;
+ int i;
+
+ /* Nothing needs to get done for the Armada 3700 */
+ if (xordev->xor_type == XOR_ARMADA_37XX)
+ return 0;
+
+ /*
+ * Loop over the cached windows to check, if the requested area
+ * is already mapped. If this the case, nothing needs to be done
+ * and we can return.
+ */
+ for (i = 0; i < WINDOW_COUNT; i++) {
+ if (addr >= xordev->win_start[i] &&
+ addr <= xordev->win_end[i]) {
+ /* Window is already mapped */
+ return 0;
+ }
+ }
+
+ /*
+ * The window is not mapped, so we need to create the new mapping
+ */
+
+ /* If no IO window is found that addr has to be located in SDRAM */
+ ret = mvebu_mbus_get_io_win_info(addr, &size, &target, &attr);
+ if (ret < 0)
+ return 0;
+
+ /*
+ * Mask the base addr 'addr' according to 'size' read back from the
+ * MBus window. Otherwise we might end up with an address located
+ * somewhere in the middle of this area here.
+ */
+ size -= 1;
+ addr &= ~size;
+
+ /*
+ * Reading one of both enabled register is enough, as they are always
+ * programmed to the identical values
+ */
+ win_enable = readl(base + WINDOW_BAR_ENABLE(0));
+
+ /* Set 'i' to the first free window to write the new values to */
+ i = ffs(~win_enable) - 1;
+ if (i >= WINDOW_COUNT)
+ return -ENOMEM;
+
+ writel((addr & 0xffff0000) | (attr << 8) | target,
+ base + WINDOW_BASE(i));
+ writel(size & 0xffff0000, base + WINDOW_SIZE(i));
+
+ /* Fill the caching variables for later use */
+ xordev->win_start[i] = addr;
+ xordev->win_end[i] = addr + size;
+
+ win_enable |= (1 << i);
+ win_enable |= 3 << (16 + (2 * i));
+ writel(win_enable, base + WINDOW_BAR_ENABLE(0));
+ writel(win_enable, base + WINDOW_BAR_ENABLE(1));
+
+ return 0;
+}
+
static struct dma_async_tx_descriptor *
mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
unsigned int src_cnt, size_t len, unsigned long flags)
{
struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan);
struct mv_xor_desc_slot *sw_desc;
+ int ret;
if (unlikely(len < MV_XOR_MIN_BYTE_COUNT))
return NULL;
@@ -486,6 +564,11 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
"%s src_cnt: %d len: %zu dest %pad flags: %ld\n",
__func__, src_cnt, len, &dest, flags);
+ /* Check if a new window needs to get added for 'dest' */
+ ret = mv_xor_add_io_win(mv_chan, dest);
+ if (ret)
+ return NULL;
+
sw_desc = mv_chan_alloc_slot(mv_chan);
if (sw_desc) {
sw_desc->type = DMA_XOR;
@@ -493,8 +576,13 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
mv_desc_init(sw_desc, dest, len, flags);
if (mv_chan->op_in_desc == XOR_MODE_IN_DESC)
mv_desc_set_mode(sw_desc);
- while (src_cnt--)
+ while (src_cnt--) {
+ /* Check if a new window needs to get added for 'src' */
+ ret = mv_xor_add_io_win(mv_chan, src[src_cnt]);
+ if (ret)
+ return NULL;
mv_desc_set_src_addr(sw_desc, src_cnt, src[src_cnt]);
+ }
}
dev_dbg(mv_chan_to_devp(mv_chan),
@@ -959,6 +1047,7 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
mv_chan->op_in_desc = XOR_MODE_IN_DESC;
dma_dev = &mv_chan->dmadev;
+ mv_chan->xordev = xordev;
/*
* These source and destination dummy buffers are used to implement
@@ -1086,6 +1175,10 @@ mv_xor_conf_mbus_windows(struct mv_xor_device *xordev,
dram->mbus_dram_target_id, base + WINDOW_BASE(i));
writel((cs->size - 1) & 0xffff0000, base + WINDOW_SIZE(i));
+ /* Fill the caching variables for later use */
+ xordev->win_start[i] = cs->base;
+ xordev->win_end[i] = cs->base + cs->size - 1;
+
win_enable |= (1 << i);
win_enable |= 3 << (16 + (2 * i));
}
diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h
index bf56e08..88eeab2 100644
--- a/drivers/dma/mv_xor.h
+++ b/drivers/dma/mv_xor.h
@@ -80,12 +80,17 @@
#define WINDOW_BAR_ENABLE(chan) (0x40 + ((chan) << 2))
#define WINDOW_OVERRIDE_CTRL(chan) (0xA0 + ((chan) << 2))
+#define WINDOW_COUNT 8
+
struct mv_xor_device {
void __iomem *xor_base;
void __iomem *xor_high_base;
struct clk *clk;
struct mv_xor_chan *channels[MV_XOR_MAX_CHANNELS];
int xor_type;
+
+ u32 win_start[WINDOW_COUNT];
+ u32 win_end[WINDOW_COUNT];
};
/**
@@ -127,6 +132,8 @@ struct mv_xor_chan {
char dummy_dst[MV_XOR_MIN_BYTE_COUNT];
dma_addr_t dummy_src_addr, dummy_dst_addr;
u32 saved_config_reg, saved_int_mask_reg;
+
+ struct mv_xor_device *xordev;
};
/**
--
2.9.3
More information about the linux-arm-kernel
mailing list