* [patch 2.6.25-rc8] spi_imx updates
@ 2008-04-07 5:57 David Brownell
0 siblings, 0 replies; only message in thread
From: David Brownell @ 2008-04-07 5:57 UTC (permalink / raw)
To: Andrew Morton
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f, Andrea Paterniani
From: Andrea Paterniani <a.paterniani-03BXCEkGbFHYGGNLXY5/rw@public.gmane.org>
Updates to the i.MX SPI controller driver:
1) Some comments changed and/or added.
2) End of transfers is now managed on TXFIFO empty interrupt after the
last write to TXFIFO. This speeds interrupt execution by removing
the wait for TXFIFO to become empty. On TXFIFO empty interrupt the
handler needs only to poll for the end of the ongoing transaction
(SPI_CONTROL_XCH) to close the transfer.
(2.1) Write only transfers are closed flushing RXFIFO.
(2.2) Read transfers are closed reading trailing bytes from RXFIFO.
(2.3) Read transfers where RXFIFO overrun occurred are closed by
flushing RXFIFO and aborting the message.
3) Fifos are now flushed via SPI disable after the end of ongoing
transaction.
Signed-off-by: Andrea Paterniani <a.paterniani-03BXCEkGbFHYGGNLXY5/rw@public.gmane.org>
---
drivers/spi/spi_imx.c | 223 +++++++++++++++++++++++++-------------------------
1 file changed, 114 insertions(+), 109 deletions(-)
--- at91.orig/drivers/spi/spi_imx.c 2008-02-19 00:07:16.000000000 -0800
+++ at91/drivers/spi/spi_imx.c 2008-04-06 22:37:42.000000000 -0700
@@ -270,19 +270,26 @@ struct chip_data {
static void pump_messages(struct work_struct *work);
-static int flush(struct driver_data *drv_data)
+static void flush(struct driver_data *drv_data)
{
- unsigned long limit = loops_per_jiffy << 1;
void __iomem *regs = drv_data->regs;
- volatile u32 d;
+ u32 control;
dev_dbg(&drv_data->pdev->dev, "flush\n");
+
+ /* Wait for end of transaction */
do {
- while (readl(regs + SPI_INT_STATUS) & SPI_STATUS_RR)
- d = readl(regs + SPI_RXDATA);
- } while ((readl(regs + SPI_CONTROL) & SPI_CONTROL_XCH) && limit--);
+ control = readl(regs + SPI_CONTROL);
+ } while (control & SPI_CONTROL_XCH);
+
+ /* Release chip select if requested, transfer delays are
+ handled in pump_transfers */
+ if (drv_data->cs_change)
+ drv_data->cs_control(SPI_CS_DEASSERT);
- return limit;
+ /* Disable SPI to flush FIFOs */
+ writel(control & ~SPI_CONTROL_SPIEN, regs + SPI_CONTROL);
+ writel(control, regs + SPI_CONTROL);
}
static void restore_state(struct driver_data *drv_data)
@@ -570,6 +577,7 @@ static void giveback(struct spi_message
writel(0, regs + SPI_INT_STATUS);
writel(0, regs + SPI_DMA);
+ /* Unconditioned deselct */
drv_data->cs_control(SPI_CS_DEASSERT);
message->state = NULL;
@@ -592,13 +600,10 @@ static void dma_err_handler(int channel,
/* Disable both rx and tx dma channels */
imx_dma_disable(drv_data->rx_channel);
imx_dma_disable(drv_data->tx_channel);
-
- if (flush(drv_data) == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_err_handler - flush failed\n");
-
unmap_dma_buffers(drv_data);
+ flush(drv_data);
+
msg->state = ERROR_STATE;
tasklet_schedule(&drv_data->pump_transfers);
}
@@ -612,8 +617,7 @@ static void dma_tx_handler(int channel,
imx_dma_disable(channel);
/* Now waits for TX FIFO empty */
- writel(readl(drv_data->regs + SPI_INT_STATUS) | SPI_INTEN_TE,
- drv_data->regs + SPI_INT_STATUS);
+ writel(SPI_INTEN_TE, drv_data->regs + SPI_INT_STATUS);
}
static irqreturn_t dma_transfer(struct driver_data *drv_data)
@@ -621,19 +625,18 @@ static irqreturn_t dma_transfer(struct d
u32 status;
struct spi_message *msg = drv_data->cur_msg;
void __iomem *regs = drv_data->regs;
- unsigned long limit;
status = readl(regs + SPI_INT_STATUS);
- if ((status & SPI_INTEN_RO) && (status & SPI_STATUS_RO)) {
+ if ((status & (SPI_INTEN_RO | SPI_STATUS_RO))
+ == (SPI_INTEN_RO | SPI_STATUS_RO)) {
writel(status & ~SPI_INTEN, regs + SPI_INT_STATUS);
+ imx_dma_disable(drv_data->tx_channel);
imx_dma_disable(drv_data->rx_channel);
unmap_dma_buffers(drv_data);
- if (flush(drv_data) == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_transfer - flush failed\n");
+ flush(drv_data);
dev_warn(&drv_data->pdev->dev,
"dma_transfer - fifo overun\n");
@@ -649,20 +652,17 @@ static irqreturn_t dma_transfer(struct d
if (drv_data->rx) {
/* Wait end of transfer before read trailing data */
- limit = loops_per_jiffy << 1;
- while ((readl(regs + SPI_CONTROL) & SPI_CONTROL_XCH) &&
- limit--);
-
- if (limit == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_transfer - end of tx failed\n");
- else
- dev_dbg(&drv_data->pdev->dev,
- "dma_transfer - end of tx\n");
+ while (readl(regs + SPI_CONTROL) & SPI_CONTROL_XCH)
+ cpu_relax();
imx_dma_disable(drv_data->rx_channel);
unmap_dma_buffers(drv_data);
+ /* Release chip select if requested, transfer delays are
+ handled in pump_transfers() */
+ if (drv_data->cs_change)
+ drv_data->cs_control(SPI_CS_DEASSERT);
+
/* Calculate number of trailing data and read them */
dev_dbg(&drv_data->pdev->dev,
"dma_transfer - test = 0x%08X\n",
@@ -676,19 +676,12 @@ static irqreturn_t dma_transfer(struct d
/* Write only transfer */
unmap_dma_buffers(drv_data);
- if (flush(drv_data) == 0)
- dev_err(&drv_data->pdev->dev,
- "dma_transfer - flush failed\n");
+ flush(drv_data);
}
/* End of transfer, update total byte transfered */
msg->actual_length += drv_data->len;
- /* Release chip select if requested, transfer delays are
- handled in pump_transfers() */
- if (drv_data->cs_change)
- drv_data->cs_control(SPI_CS_DEASSERT);
-
/* Move to next transfer */
msg->state = next_transfer(drv_data);
@@ -711,44 +704,43 @@ static irqreturn_t interrupt_wronly_tran
status = readl(regs + SPI_INT_STATUS);
- while (status & SPI_STATUS_TH) {
+ if (status & SPI_INTEN_TE) {
+ /* TXFIFO Empty Interrupt on the last transfered word */
+ writel(status & ~SPI_INTEN, regs + SPI_INT_STATUS);
dev_dbg(&drv_data->pdev->dev,
- "interrupt_wronly_transfer - status = 0x%08X\n", status);
+ "interrupt_wronly_transfer - end of tx\n");
- /* Pump data */
- if (write(drv_data)) {
- writel(readl(regs + SPI_INT_STATUS) & ~SPI_INTEN,
- regs + SPI_INT_STATUS);
+ flush(drv_data);
- dev_dbg(&drv_data->pdev->dev,
- "interrupt_wronly_transfer - end of tx\n");
+ /* Update total byte transfered */
+ msg->actual_length += drv_data->len;
- if (flush(drv_data) == 0)
- dev_err(&drv_data->pdev->dev,
- "interrupt_wronly_transfer - "
- "flush failed\n");
+ /* Move to next transfer */
+ msg->state = next_transfer(drv_data);
- /* End of transfer, update total byte transfered */
- msg->actual_length += drv_data->len;
+ /* Schedule transfer tasklet */
+ tasklet_schedule(&drv_data->pump_transfers);
- /* Release chip select if requested, transfer delays are
- handled in pump_transfers */
- if (drv_data->cs_change)
- drv_data->cs_control(SPI_CS_DEASSERT);
+ return IRQ_HANDLED;
+ } else {
+ while (status & SPI_STATUS_TH) {
+ dev_dbg(&drv_data->pdev->dev,
+ "interrupt_wronly_transfer - status = 0x%08X\n",
+ status);
- /* Move to next transfer */
- msg->state = next_transfer(drv_data);
+ /* Pump data */
+ if (write(drv_data)) {
+ /* End of TXFIFO writes,
+ now wait until TXFIFO is empty */
+ writel(SPI_INTEN_TE, regs + SPI_INT_STATUS);
+ return IRQ_HANDLED;
+ }
- /* Schedule transfer tasklet */
- tasklet_schedule(&drv_data->pump_transfers);
+ status = readl(regs + SPI_INT_STATUS);
- return IRQ_HANDLED;
+ /* We did something */
+ handled = IRQ_HANDLED;
}
-
- status = readl(regs + SPI_INT_STATUS);
-
- /* We did something */
- handled = IRQ_HANDLED;
}
return handled;
@@ -758,45 +750,31 @@ static irqreturn_t interrupt_transfer(st
{
struct spi_message *msg = drv_data->cur_msg;
void __iomem *regs = drv_data->regs;
- u32 status;
+ u32 status, control;
irqreturn_t handled = IRQ_NONE;
unsigned long limit;
status = readl(regs + SPI_INT_STATUS);
- while (status & (SPI_STATUS_TH | SPI_STATUS_RO)) {
+ if (status & SPI_INTEN_TE) {
+ /* TXFIFO Empty Interrupt on the last transfered word */
+ writel(status & ~SPI_INTEN, regs + SPI_INT_STATUS);
dev_dbg(&drv_data->pdev->dev,
- "interrupt_transfer - status = 0x%08X\n", status);
-
- if (status & SPI_STATUS_RO) {
- writel(readl(regs + SPI_INT_STATUS) & ~SPI_INTEN,
- regs + SPI_INT_STATUS);
-
- dev_warn(&drv_data->pdev->dev,
- "interrupt_transfer - fifo overun\n"
- " data not yet written = %d\n"
- " data not yet read = %d\n",
- data_to_write(drv_data),
- data_to_read(drv_data));
-
- if (flush(drv_data) == 0)
- dev_err(&drv_data->pdev->dev,
- "interrupt_transfer - flush failed\n");
-
- msg->state = ERROR_STATE;
- tasklet_schedule(&drv_data->pump_transfers);
+ "interrupt_transfer - end of tx\n");
- return IRQ_HANDLED;
- }
-
- /* Pump data */
- read(drv_data);
- if (write(drv_data)) {
- writel(readl(regs + SPI_INT_STATUS) & ~SPI_INTEN,
- regs + SPI_INT_STATUS);
+ if (msg->state == ERROR_STATE) {
+ /* RXFIFO overrun was detected and message aborted */
+ flush(drv_data);
+ } else {
+ /* Wait for end of transaction */
+ do {
+ control = readl(regs + SPI_CONTROL);
+ } while (control & SPI_CONTROL_XCH);
- dev_dbg(&drv_data->pdev->dev,
- "interrupt_transfer - end of tx\n");
+ /* Release chip select if requested, transfer delays are
+ handled in pump_transfers */
+ if (drv_data->cs_change)
+ drv_data->cs_control(SPI_CS_DEASSERT);
/* Read trailing bytes */
limit = loops_per_jiffy << 1;
@@ -810,27 +788,54 @@ static irqreturn_t interrupt_transfer(st
dev_dbg(&drv_data->pdev->dev,
"interrupt_transfer - end of rx\n");
- /* End of transfer, update total byte transfered */
+ /* Update total byte transfered */
msg->actual_length += drv_data->len;
- /* Release chip select if requested, transfer delays are
- handled in pump_transfers */
- if (drv_data->cs_change)
- drv_data->cs_control(SPI_CS_DEASSERT);
-
/* Move to next transfer */
msg->state = next_transfer(drv_data);
+ }
- /* Schedule transfer tasklet */
- tasklet_schedule(&drv_data->pump_transfers);
+ /* Schedule transfer tasklet */
+ tasklet_schedule(&drv_data->pump_transfers);
- return IRQ_HANDLED;
- }
+ return IRQ_HANDLED;
+ } else {
+ while (status & (SPI_STATUS_TH | SPI_STATUS_RO)) {
+ dev_dbg(&drv_data->pdev->dev,
+ "interrupt_transfer - status = 0x%08X\n",
+ status);
+
+ if (status & SPI_STATUS_RO) {
+ /* RXFIFO overrun, abort message end wait
+ until TXFIFO is empty */
+ writel(SPI_INTEN_TE, regs + SPI_INT_STATUS);
+
+ dev_warn(&drv_data->pdev->dev,
+ "interrupt_transfer - fifo overun\n"
+ " data not yet written = %d\n"
+ " data not yet read = %d\n",
+ data_to_write(drv_data),
+ data_to_read(drv_data));
+
+ msg->state = ERROR_STATE;
+
+ return IRQ_HANDLED;
+ }
- status = readl(regs + SPI_INT_STATUS);
+ /* Pump data */
+ read(drv_data);
+ if (write(drv_data)) {
+ /* End of TXFIFO writes,
+ now wait until TXFIFO is empty */
+ writel(SPI_INTEN_TE, regs + SPI_INT_STATUS);
+ return IRQ_HANDLED;
+ }
- /* We did something */
- handled = IRQ_HANDLED;
+ status = readl(regs + SPI_INT_STATUS);
+
+ /* We did something */
+ handled = IRQ_HANDLED;
+ }
}
return handled;
-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference
Register now and save $200. Hurry, offer ends at 11:59 p.m.,
Monday, April 7! Use priority code J8TLD2.
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2008-04-07 5:57 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-04-07 5:57 [patch 2.6.25-rc8] spi_imx updates David Brownell
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).