mxs-dma : rewrite the last parameter of mxs_dma_prep_slave_sg()
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Mon Mar 26 20:59:12 EDT 2012
Gitweb: http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=921de864b7c6413f15224d8f5e677541e8e1ac6d
Commit: 921de864b7c6413f15224d8f5e677541e8e1ac6d
Parent: 3946860409130038ef6e0e5c50f2203053eae2b7
Author: Huang Shijie <b32955 at freescale.com>
AuthorDate: Thu Feb 16 14:17:33 2012 +0800
Committer: David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Tue Mar 27 00:37:28 2012 +0100
mxs-dma : rewrite the last parameter of mxs_dma_prep_slave_sg()
[1] Background :
The GPMI does ECC read page operation with a DMA chain consist of three DMA
Command Structures. The middle one of the chain is used to enable the BCH,
and read out the NAND page.
The WAIT4END(wait for command end) is a comunication signal between
the GPMI and MXS-DMA.
[2] The current DMA code sets the WAIT4END bit at the last one, such as:
+-----+ +-----+ +-----+
| cmd | ------------> | cmd | ------------------> | cmd |
+-----+ +-----+ +-----+
^
|
|
set WAIT4END here
This chain works fine in the mx23/mx28.
[3] But in the new GPMI version (used in MX50/MX60), the WAIT4END bit should
be set not only at the last DMA Command Structure,
but also at the middle one, such as:
+-----+ +-----+ +-----+
| cmd | ------------> | cmd | ------------------> | cmd |
+-----+ +-----+ +-----+
^ ^
| |
| |
set WAIT4END here too set WAIT4END here
If we do not set WAIT4END, the BCH maybe stalls in "ECC reading page" state.
In the next ECC write page operation, a DMA-timeout occurs.
This has been catched in the MX6Q board.
[4] In order to fix the bug, rewrite the last parameter of mxs_dma_prep_slave_sg(),
and use the dma_ctrl_flags:
---------------------------------------------------------
DMA_PREP_INTERRUPT : append a new DMA Command Structrue.
DMA_CTRL_ACK : set the WAIT4END bit for this DMA Command Structure.
---------------------------------------------------------
[5] changes to the relative drivers:
<1> For mxs-mmc driver, just use the new flags, do not change any logic.
<2> For gpmi-nand driver, and use the new flags to set the DMA
chain, especially for ecc read page.
Acked-by: Shawn Guo <shawn.guo at linaro.org>
Signed-off-by: Huang Shijie <b32955 at freescale.com>
Acked-by: Vinod Koul <vinod.koul at linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
drivers/dma/mxs-dma.c | 32 ++++++++++++++++++++++++++++----
drivers/mmc/host/mxs-mmc.c | 10 +++++-----
drivers/mtd/nand/gpmi-nand/gpmi-lib.c | 19 +++++++++++++------
3 files changed, 46 insertions(+), 15 deletions(-)
diff --git a/drivers/dma/mxs-dma.c b/drivers/dma/mxs-dma.c
index 0afcedb..0ddfd30 100644
--- a/drivers/dma/mxs-dma.c
+++ b/drivers/dma/mxs-dma.c
@@ -349,10 +349,32 @@ static void mxs_dma_free_chan_resources(struct dma_chan *chan)
clk_disable_unprepare(mxs_dma->clk);
}
+/*
+ * How to use the flags for ->device_prep_slave_sg() :
+ * [1] If there is only one DMA command in the DMA chain, the code should be:
+ * ......
+ * ->device_prep_slave_sg(DMA_CTRL_ACK);
+ * ......
+ * [2] If there are two DMA commands in the DMA chain, the code should be
+ * ......
+ * ->device_prep_slave_sg(0);
+ * ......
+ * ->device_prep_slave_sg(DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+ * ......
+ * [3] If there are more than two DMA commands in the DMA chain, the code
+ * should be:
+ * ......
+ * ->device_prep_slave_sg(0); // First
+ * ......
+ * ->device_prep_slave_sg(DMA_PREP_INTERRUPT [| DMA_CTRL_ACK]);
+ * ......
+ * ->device_prep_slave_sg(DMA_PREP_INTERRUPT | DMA_CTRL_ACK); // Last
+ * ......
+ */
static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
struct dma_chan *chan, struct scatterlist *sgl,
unsigned int sg_len, enum dma_transfer_direction direction,
- unsigned long append)
+ unsigned long flags)
{
struct mxs_dma_chan *mxs_chan = to_mxs_dma_chan(chan);
struct mxs_dma_engine *mxs_dma = mxs_chan->mxs_dma;
@@ -360,6 +382,7 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
struct scatterlist *sg;
int i, j;
u32 *pio;
+ bool append = flags & DMA_PREP_INTERRUPT;
int idx = append ? mxs_chan->desc_count : 0;
if (mxs_chan->status == DMA_IN_PROGRESS && !append)
@@ -386,7 +409,6 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
ccw->bits |= CCW_CHAIN;
ccw->bits &= ~CCW_IRQ;
ccw->bits &= ~CCW_DEC_SEM;
- ccw->bits &= ~CCW_WAIT4END;
} else {
idx = 0;
}
@@ -401,7 +423,8 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
ccw->bits = 0;
ccw->bits |= CCW_IRQ;
ccw->bits |= CCW_DEC_SEM;
- ccw->bits |= CCW_WAIT4END;
+ if (flags & DMA_CTRL_ACK)
+ ccw->bits |= CCW_WAIT4END;
ccw->bits |= CCW_HALT_ON_TERM;
ccw->bits |= CCW_TERM_FLUSH;
ccw->bits |= BF_CCW(sg_len, PIO_NUM);
@@ -432,7 +455,8 @@ static struct dma_async_tx_descriptor *mxs_dma_prep_slave_sg(
ccw->bits &= ~CCW_CHAIN;
ccw->bits |= CCW_IRQ;
ccw->bits |= CCW_DEC_SEM;
- ccw->bits |= CCW_WAIT4END;
+ if (flags & DMA_CTRL_ACK)
+ ccw->bits |= CCW_WAIT4END;
}
}
}
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index e5ea2b1..4062812 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c
@@ -305,7 +305,7 @@ static irqreturn_t mxs_mmc_irq_handler(int irq, void *dev_id)
}
static struct dma_async_tx_descriptor *mxs_mmc_prep_dma(
- struct mxs_mmc_host *host, unsigned int append)
+ struct mxs_mmc_host *host, unsigned long flags)
{
struct dma_async_tx_descriptor *desc;
struct mmc_data *data = host->data;
@@ -325,7 +325,7 @@ static struct dma_async_tx_descriptor *mxs_mmc_prep_dma(
}
desc = host->dmach->device->device_prep_slave_sg(host->dmach,
- sgl, sg_len, host->slave_dirn, append);
+ sgl, sg_len, host->slave_dirn, flags);
if (desc) {
desc->callback = mxs_mmc_dma_irq_callback;
desc->callback_param = host;
@@ -358,7 +358,7 @@ static void mxs_mmc_bc(struct mxs_mmc_host *host)
host->ssp_pio_words[2] = cmd1;
host->dma_dir = DMA_NONE;
host->slave_dirn = DMA_TRANS_NONE;
- desc = mxs_mmc_prep_dma(host, 0);
+ desc = mxs_mmc_prep_dma(host, DMA_CTRL_ACK);
if (!desc)
goto out;
@@ -398,7 +398,7 @@ static void mxs_mmc_ac(struct mxs_mmc_host *host)
host->ssp_pio_words[2] = cmd1;
host->dma_dir = DMA_NONE;
host->slave_dirn = DMA_TRANS_NONE;
- desc = mxs_mmc_prep_dma(host, 0);
+ desc = mxs_mmc_prep_dma(host, DMA_CTRL_ACK);
if (!desc)
goto out;
@@ -526,7 +526,7 @@ static void mxs_mmc_adtc(struct mxs_mmc_host *host)
host->data = data;
host->dma_dir = dma_data_dir;
host->slave_dirn = slave_dirn;
- desc = mxs_mmc_prep_dma(host, 1);
+ desc = mxs_mmc_prep_dma(host, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc)
goto out;
diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
index 7db6555..5e3c505 100644
--- a/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
+++ b/drivers/mtd/nand/gpmi-nand/gpmi-lib.c
@@ -849,7 +849,9 @@ int gpmi_send_command(struct gpmi_nand_data *this)
sg_init_one(sgl, this->cmd_buffer, this->command_length);
dma_map_sg(this->dev, sgl, 1, DMA_TO_DEVICE);
desc = channel->device->device_prep_slave_sg(channel,
- sgl, 1, DMA_MEM_TO_DEV, 1);
+ sgl, 1, DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+
if (!desc) {
pr_err("step 2 error\n");
return -1;
@@ -891,7 +893,8 @@ int gpmi_send_data(struct gpmi_nand_data *this)
/* [2] send DMA request */
prepare_data_dma(this, DMA_TO_DEVICE);
desc = channel->device->device_prep_slave_sg(channel, &this->data_sgl,
- 1, DMA_MEM_TO_DEV, 1);
+ 1, DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
pr_err("step 2 error\n");
return -1;
@@ -927,7 +930,8 @@ int gpmi_read_data(struct gpmi_nand_data *this)
/* [2] : send DMA request */
prepare_data_dma(this, DMA_FROM_DEVICE);
desc = channel->device->device_prep_slave_sg(channel, &this->data_sgl,
- 1, DMA_DEV_TO_MEM, 1);
+ 1, DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
pr_err("step 2 error\n");
return -1;
@@ -974,7 +978,8 @@ int gpmi_send_page(struct gpmi_nand_data *this,
desc = channel->device->device_prep_slave_sg(channel,
(struct scatterlist *)pio,
- ARRAY_SIZE(pio), DMA_TRANS_NONE, 0);
+ ARRAY_SIZE(pio), DMA_TRANS_NONE,
+ DMA_CTRL_ACK);
if (!desc) {
pr_err("step 2 error\n");
return -1;
@@ -1038,7 +1043,8 @@ int gpmi_read_page(struct gpmi_nand_data *this,
pio[5] = auxiliary;
desc = channel->device->device_prep_slave_sg(channel,
(struct scatterlist *)pio,
- ARRAY_SIZE(pio), DMA_TRANS_NONE, 1);
+ ARRAY_SIZE(pio), DMA_TRANS_NONE,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
pr_err("step 2 error\n");
return -1;
@@ -1057,7 +1063,8 @@ int gpmi_read_page(struct gpmi_nand_data *this,
pio[1] = 0;
desc = channel->device->device_prep_slave_sg(channel,
(struct scatterlist *)pio, 2,
- DMA_TRANS_NONE, 1);
+ DMA_TRANS_NONE,
+ DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
pr_err("step 3 error\n");
return -1;
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