Re: [PATCH take #5] [libata] libata driver for bf548 on chip ATAPI controller.

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Sonic Zhang wrote:
Update:
1. Condition branch code instead of while loop from Alan Cox.
2. Condtinue in PIO mode after failing to request DMA.

Signed-off-by: Sonic Zhang <[email protected]>
---
 drivers/ata/Kconfig      |   28 +
 drivers/ata/Makefile     |    1
 drivers/ata/pata_bf54x.c | 1581 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 1610 insertions(+)

diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index b4a8d60..e679f04 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -583,4 +583,32 @@ config PATA_SCC
If unsure, say N. +config PATA_BF54X
+	tristate "Blackfin 54x ATAPI support"
+	depends on BF542 || BF548 || BF549
+	help
+	  This option enables support for the built-in ATAPI controller on
+	  Blackfin 54x family chips.
+
+	  If unsure, say N.
+
+choice
+	prompt "Blackfin 54x ATAPI mode"
+	depends on PATA_BF54X
+	default PATA_BF54X_DMA
+	help
+	  This option selects bf54x ATAPI controller working mode.
+
+config PATA_BF54X_PIO
+	bool "PIO mode"
+	help
+	  Blackfin ATAPI controller works under PIO mode.
+
+config PATA_BF54X_DMA
+	bool "DMA mode"
+	help
+	  Blackfin ATAPI controller works under DMA mode.


Given update #2 at the top of your message, I would think a more natural Kconfig setup would now be a simple "DMA support?" yes/no setting. PIO would theoretically always be present as a fallback, I would think.


diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index 8149c68..c2ecba5 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_PATA_SIS)		+= pata_sis.o
 obj-$(CONFIG_PATA_TRIFLEX)	+= pata_triflex.o
 obj-$(CONFIG_PATA_IXP4XX_CF)	+= pata_ixp4xx_cf.o
 obj-$(CONFIG_PATA_SCC)		+= pata_scc.o
+obj-$(CONFIG_PATA_BF54X)	+= pata_bf54x.o
 obj-$(CONFIG_PATA_PLATFORM)	+= pata_platform.o
 obj-$(CONFIG_PATA_ICSIDE)	+= pata_icside.o
 # Should be last but one libata driver
diff --git a/drivers/ata/pata_bf54x.c b/drivers/ata/pata_bf54x.c
new file mode 100644
index 0000000..d0f52b0
--- /dev/null
+++ b/drivers/ata/pata_bf54x.c
@@ -0,0 +1,1581 @@
+/*
+ * File:         drivers/ata/pata_bf54x.c
+ * Author:       Sonic Zhang <[email protected]>
+ *
+ * Created:
+ * Description:  ATAPI Driver for blackfin 54x

Terminology: When used alone, "ATAPI" normally refers to CD/DVD-ROM style devices. A better description would be "PATA driver for ..."


+#define DRV_NAME		"bf54x-atapi"
+#define DRV_VERSION		"0.6"

DRV_NAME should be "pata_bf54x"


+#define ATA_REG_CTRL		0x0E
+#define ATA_REG_ALTSTATUS	ATA_REG_CTRL

a simple comment at the beginning of this list, noting that these are the controller's registers, would be nice


+#define ATAPI_OFFSET_CONTROL		0x00
+#define ATAPI_OFFSET_STATUS		0x04
+#define ATAPI_OFFSET_DEV_ADDR		0x08
+#define ATAPI_OFFSET_DEV_TXBUF		0x0c
+#define ATAPI_OFFSET_DEV_RXBUF		0x10
+#define ATAPI_OFFSET_INT_MASK		0x14
+#define ATAPI_OFFSET_INT_STATUS		0x18
+#define ATAPI_OFFSET_XFER_LEN		0x1c
+#define ATAPI_OFFSET_LINE_STATUS	0x20
+#define ATAPI_OFFSET_SM_STATE		0x24
+#define ATAPI_OFFSET_TERMINATE		0x28
+#define ATAPI_OFFSET_PIO_TFRCNT		0x2c
+#define ATAPI_OFFSET_DMA_TFRCNT		0x30
+#define ATAPI_OFFSET_UMAIN_TFRCNT	0x34
+#define ATAPI_OFFSET_UDMAOUT_TFRCNT	0x38
+#define ATAPI_OFFSET_REG_TIM_0		0x40
+#define ATAPI_OFFSET_PIO_TIM_0		0x44
+#define ATAPI_OFFSET_PIO_TIM_1		0x48
+#define ATAPI_OFFSET_MULTI_TIM_0	0x50
+#define ATAPI_OFFSET_MULTI_TIM_1	0x54
+#define ATAPI_OFFSET_MULTI_TIM_2	0x58
+#define ATAPI_OFFSET_ULTRA_TIM_0	0x60
+#define ATAPI_OFFSET_ULTRA_TIM_1	0x64
+#define ATAPI_OFFSET_ULTRA_TIM_2	0x68
+#define ATAPI_OFFSET_ULTRA_TIM_3	0x6c
+
+
+/**
+ * PIO Mode - Frequency compatibility
+ */
+/* mode: 0         1         2         3         4 */
+static u32 pio_fsclk[] =
+{ 33333333, 33333333, 33333333, 33333333, 33333333 };
+
+/**
+ * MDMA Mode - Frequency compatibility
+ */
+/*               mode:      0         1         2        */
+static u32 mdma_fsclk[] = { 33333333, 33333333, 33333333 };
+
+/**
+ * UDMA Mode - Frequency compatibility
+ *
+ * UDMA5 - 100 MB/s   - SCLK  = 133 MHz
+ * UDMA4 - 66 MB/s    - SCLK >=  80 MHz
+ * UDMA3 - 44.4 MB/s  - SCLK >=  50 MHz
+ * UDMA2 - 33 MB/s    - SCLK >=  40 MHz
+ */
+/* mode: 0         1         2         3         4          5 */
+static u32 udma_fsclk[] =
+{ 33333333, 33333333, 40000000, 50000000, 80000000, 133333333 };
+
+/**
+ * Register transfer timing table
+ */
+/*               mode:       0    1    2    3    4    */
+/* Cycle Time                     */
+static u32 reg_t0min[]   = { 600, 383, 330, 180, 120 };
+/* DIOR/DIOW to end cycle         */
+static u32 reg_t2min[]   = { 290, 290, 290, 70,  25  };
+/* DIOR/DIOW asserted pulse width */
+static u32 reg_teocmin[] = { 290, 290, 290, 80,  70  };
+
+/**
+ * PIO timing table
+ */
+/*               mode:       0    1    2    3    4    */
+/* Cycle Time                     */
+static u32 pio_t0min[]   = { 600, 383, 240, 180, 120 };
+/* Address valid to DIOR/DIORW    */
+static u32 pio_t1min[]   = { 70,  50,  30,  30,  25  };
+/* DIOR/DIOW to end cycle         */
+static u32 pio_t2min[]   = { 165, 125, 100, 80,  70  };
+/* DIOR/DIOW asserted pulse width */
+static u32 pio_teocmin[] = { 165, 125, 100, 70,  25  };
+/* DIOW data hold                 */
+static u32 pio_t4min[]   = { 30,  20,  15,  10,  10  };
+
+/* ******************************************************************
+ * Multiword DMA timing table
+ * ******************************************************************
+ */
+/*               mode:       0   1    2        */
+/* Cycle Time                     */
+static u32 mdma_t0min[]  = { 480, 150, 120 };
+/* DIOR/DIOW asserted pulse width */
+static u32 mdma_tdmin[]  = { 215, 80,  70  };
+/* DMACK to read data released    */
+static u32 mdma_thmin[]  = { 20,  15,  10  };
+/* DIOR/DIOW to DMACK hold        */
+static u32 mdma_tjmin[]  = { 20,  5,   5   };
+/* DIOR negated pulse width       */
+static u32 mdma_tkrmin[] = { 50,  50,  25  };
+/* DIOR negated pulse width       */
+static u32 mdma_tkwmin[] = { 215, 50,  25  };
+/* CS[1:0] valid to DIOR/DIOW     */
+static u32 mdma_tmmin[]  = { 50,  30,  25  };
+/* DMACK to read data released    */
+static u32 mdma_tzmax[]  = { 20,  25,  25  };
+
+/**
+ * Ultra DMA timing table
+ */
+/*               mode:         0    1    2    3    4    5       */
+static u32 udma_tcycmin[]  = { 112, 73,  54,  39,  25,  17 };
+static u32 udma_tdvsmin[]  = { 70,  48,  31,  20,  7,   5  };
+static u32 udma_tenvmax[]  = { 70,  70,  70,  55,  55,  50 };
+static u32 udma_trpmin[]   = { 160, 125, 100, 100, 100, 85 };
+static u32 udma_tmin[]     = { 5,   5,   5,   5,   3,   3  };
+
+
+static u32 udma_tmlimin = 20;
+static u32 udma_tzahmin = 20;
+static u32 udma_tenvmin = 20;
+static u32 udma_tackmin = 20;
+static u32 udma_tssmin = 50;

how many of these can be marked 'static const'?


+static unsigned short num_clocks_min(unsigned long tmin,
+				unsigned long fsclk)
+{
+	unsigned long tmp ;
+	unsigned short result;
+
+	tmp = tmin * (fsclk/1000/1000) / 1000;
+	result = (unsigned short)tmp;
+	if ((tmp*1000*1000) < (tmin*(fsclk/1000))) {
+		result++;
+	}
+
+	return result;
+}
+
+/**
+ *	bfin_set_piomode - Initialize host controller PATA PIO timings
+ *	@ap: Port whose timings we are configuring
+ *	@adev: um
+ *
+ *	Set PIO mode for device.
+ *
+ *	LOCKING:
+ *	None (inherited from caller).
+ */
+
+static void bfin_set_piomode(struct ata_port *ap, struct ata_device *adev)
+{
+	int mode = adev->pio_mode - XFER_PIO_0;
+	unsigned long base = (unsigned long)ap->ioaddr.ctl_addr;


(added Bryan Wu to CC)

Someone needs to need fix the bfin architecture: the addresses on the bfin_read/bfin_write functions should be 'void __iomem *' not unsigned long.

Also, it would make this driver quite a bit smaller if you can use the ioread/iowrite (iomap) functions provided by the architecture. Then you can use a lot of the standard libata helper functions.



+	unsigned int fsclk = get_sclk();
+	unsigned short teoc_reg, t2_reg, teoc_pio;
+	unsigned short t4_reg, t2_pio, t1_reg;
+	unsigned short n0, n6, t6min = 5;
+
+	/* the most restrictive timing value is t6 and tc, the DIOW - data hold
+	* If one SCLK pulse is longer than this minimum value then register
+	* transfers cannot be supported at this frequency.
+	*/
+	n6 = num_clocks_min(t6min, fsclk);
+	if (mode >= 0 && mode <= 4 && n6 >= 1) {
+		pr_debug("set piomode: mode=%d, fsclk=%ud\n", mode, fsclk);
+		/* calculate the timing values for register transfers. */
+		while (mode > 0 && pio_fsclk[mode] > fsclk) {
+			mode--;
+		}

In Linux kernel code, we prefer that single C statements not be surrounded by [optional] braces.


+		/* DIOR/DIOW to end cycle time */
+		t2_reg = num_clocks_min(reg_t2min[mode], fsclk);
+		/* DIOR/DIOW asserted pulse width */
+		teoc_reg = num_clocks_min(reg_teocmin[mode], fsclk);
+		/* Cycle Time */
+		n0  = num_clocks_min(reg_t0min[mode], fsclk);
+
+		/* increase t2 until we meed the minimum cycle length */
+		if (t2_reg + teoc_reg < n0)
+			t2_reg = n0 - teoc_reg;
+
+		/* calculate the timing values for pio transfers. */
+
+		/* DIOR/DIOW to end cycle time */
+		t2_pio = num_clocks_min(pio_t2min[mode], fsclk);
+		/* DIOR/DIOW asserted pulse width */
+		teoc_pio = num_clocks_min(pio_teocmin[mode], fsclk);
+		/* Cycle Time */
+		n0  = num_clocks_min(pio_t0min[mode], fsclk);
+
+		/* increase t2 until we meed the minimum cycle length */
+		if (t2_pio + teoc_pio < n0)
+			t2_pio = n0 - teoc_pio;
+
+		/* Address valid to DIOR/DIORW */
+		t1_reg = num_clocks_min(pio_t1min[mode], fsclk);
+
+		/* DIOW data hold */
+		t4_reg = num_clocks_min(pio_t4min[mode], fsclk);
+
+		ATAPI_SET_REG_TIM_0(base, (teoc_reg<<8 | t2_reg));
+		ATAPI_SET_PIO_TIM_0(base, (t4_reg<<12 | t2_pio<<4 | t1_reg));
+		ATAPI_SET_PIO_TIM_1(base, teoc_pio);
+		if (mode > 2) {
+			ATAPI_SET_CONTROL(base,
+				ATAPI_GET_CONTROL(base) | IORDY_EN);
+		} else {
+			ATAPI_SET_CONTROL(base,
+				ATAPI_GET_CONTROL(base) & ~IORDY_EN);
+		}
+
+		/* Disable host ATAPI PIO interrupts */
+		ATAPI_SET_INT_MASK(base, ATAPI_GET_INT_MASK(base)
+			& ~(PIO_DONE_MASK | HOST_TERM_XFER_MASK));
+		SSYNC();
+	}
+}
+
+/**
+ *	bfin_set_dmamode - Initialize host controller PATA DMA timings
+ *	@ap: Port whose timings we are configuring
+ *	@adev: um
+ *	@udma: udma mode, 0 - 6
+ *
+ *	Set UDMA mode for device.
+ *
+ *	LOCKING:
+ *	None (inherited from caller).
+ */
+
+static void bfin_set_dmamode (struct ata_port *ap, struct ata_device *adev)
+{
+	int mode;
+	unsigned long base = (unsigned long)ap->ioaddr.ctl_addr;
+	unsigned long fsclk = get_sclk();
+	unsigned short tenv, tack, tcyc_tdvs, tdvs, tmli, tss, trp, tzah;
+	unsigned short tm, td, tkr, tkw, teoc, th;
+	unsigned short n0, nf, tfmin = 5;
+	unsigned short nmin, tcyc;

+/**
+ *
+ *    Function:       wait_complete
+ *
+ *    Description:    Waits the interrupt from device
+ *
+ */
+static void inline wait_complete(unsigned long base, unsigned short mask)
+{
+	unsigned short status;
+
+	do {
+		status = ATAPI_GET_INT_STATUS(base) & mask;
+	} while (!status);
+
+	ATAPI_SET_INT_STATUS(base, mask);
+}

no infinite loops, please. always make sure the function errors out after (100? 1000? 100000?) iterations.





+ */
+
+static void bfin_bmdma_setup (struct ata_queued_cmd *qc)
+{
+	unsigned short config = WDSIZE_16;
+	struct scatterlist *sg;
+
+	pr_debug("in atapi dma setup\n");
+	/* Program the ATA_CTRL register with dir */
+	if (qc->tf.flags & ATA_TFLAG_WRITE) {
+		/* fill the ATAPI DMA controller */
+		set_dma_config(CH_ATAPI_TX, config);
+		set_dma_x_modify(CH_ATAPI_TX, 2);
+		ata_for_each_sg(sg, qc) {
+			set_dma_start_addr(CH_ATAPI_TX, sg_dma_address(sg));
+			set_dma_x_count(CH_ATAPI_TX, sg_dma_len(sg) >> 1);
+		}
+	} else {
+		config |= WNR;
+		/* fill the ATAPI DMA controller */
+		set_dma_config(CH_ATAPI_RX, config);
+		set_dma_x_modify(CH_ATAPI_RX, 2);
+		ata_for_each_sg(sg, qc) {
+			set_dma_start_addr(CH_ATAPI_RX, sg_dma_address(sg));
+			set_dma_x_count(CH_ATAPI_RX, sg_dma_len(sg) >> 1);
+		}
+	}
+}
+
+/**
+ *	bfin_bmdma_start - Start an IDE DMA transaction
+ *	@qc: Info associated with this ATA transaction.
+ *
+ *	Note: Original code is ata_bmdma_start().
+ */
+
+static void bfin_bmdma_start (struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	unsigned long base = (unsigned long)ap->ioaddr.ctl_addr;
+	struct scatterlist *sg;
+
+	pr_debug("in atapi dma start\n");
+	if (ap->udma_mask || ap->mwdma_mask) {

invert this test, and have it return from the function early if so.

this allows you to un-indent the following section of code, making it easier to read.


+		/* start ATAPI DMA controller*/
+		if (qc->tf.flags & ATA_TFLAG_WRITE) {

a comment explaining what the flush_dcache_range() loop is accomplishing would be nice


+			ata_for_each_sg(sg, qc) {
+				flush_dcache_range(sg_dma_address(sg),
+					sg_dma_address(sg) + sg_dma_len(sg));
+			}
+			enable_dma(CH_ATAPI_TX);
+			pr_debug("enable udma write\n");
+
+			/* Send ATA DMA write command */
+			bfin_exec_command(ap, &qc->tf);
+
+			/* set ATA DMA write direction */
+			ATAPI_SET_CONTROL(base, (ATAPI_GET_CONTROL(base)
+				| XFER_DIR));
+		} else {
+			enable_dma(CH_ATAPI_RX);
+			pr_debug("enable udma read\n");
+
+			/* Send ATA DMA read command */
+			bfin_exec_command(ap, &qc->tf);
+
+			/* set ATA DMA read direction */
+			ATAPI_SET_CONTROL(base, (ATAPI_GET_CONTROL(base)
+				& ~XFER_DIR));
+		}
+
+		/* Reset all transfer count */
+		ATAPI_SET_CONTROL(base,
+			ATAPI_GET_CONTROL(base) | TFRCNT_RST);
+
+		/* Set transfer length to buffer len */
+		ata_for_each_sg(sg, qc) {
+			ATAPI_SET_XFER_LEN(base, (sg_dma_len(sg) >> 1));
+		}
+
+		/* Enable ATA DMA operation*/
+		if (ap->udma_mask) {
+			ATAPI_SET_CONTROL(base, ATAPI_GET_CONTROL(base)
+				| ULTRA_START);
+		} else {
+			ATAPI_SET_CONTROL(base, ATAPI_GET_CONTROL(base)
+				| MULTI_START);
+		}
+	}
+}
+
+/**
+ *	bfin_bmdma_stop - Stop IDE DMA transfer
+ *	@qc: Command we are ending DMA for
+ */
+
+static void bfin_bmdma_stop (struct ata_queued_cmd *qc)
+{
+	struct ata_port *ap = qc->ap;
+	struct scatterlist *sg;
+
+	pr_debug("in atapi dma stop\n");
+	if (ap->udma_mask || ap->mwdma_mask) {

ditto -- invert test and return early.

then, un-indent all code following.


+		/* stop ATAPI DMA controller*/
+		if (qc->tf.flags & ATA_TFLAG_WRITE) {
+			disable_dma(CH_ATAPI_TX);
+		} else {
+			disable_dma(CH_ATAPI_RX);
+			if (ap->hsm_task_state & HSM_ST_LAST) {

ditto -- a comment explaining the invalidate_dcache_range() loop would be nice.

it really looks like this should be hidden inside the architecture's dma functions, I would think?


+				ata_for_each_sg(sg, qc) {
+					invalidate_dcache_range(
+						sg_dma_address(sg),
+						sg_dma_address(sg)
+						+ sg_dma_len(sg));
+				}
+			}
+		}
+	}

you appear to be missing an important error handling operation: thaw


+static void bfin_bmdma_freeze (struct ata_port *ap)
+{
+	unsigned long base = (unsigned long)ap->ioaddr.ctl_addr;
+
+	pr_debug("in atapi dma freeze\n");
+	ap->ctl |= ATA_NIEN;
+	ap->last_ctl = ap->ctl;
+
+	write_atapi_register(base, ATA_REG_CTRL, ap->ctl);
+
+	/* Under certain circumstances, some controllers raise IRQ on
+	 * ATA_NIEN manipulation.  Also, many controllers fail to mask
+	 * previously pending IRQ on ATA_NIEN assertion.  Clear it.
+	 */
+	ata_chk_status(ap);
+
+	ap->ops->irq_clear(ap);

All occurences of "ap->ops->..." in this driver may be replaced with direct calls to functions.



+ *	bfin_std_postreset - standard postreset callback
+ *	@ap: the target ata_port
+ *	@classes: classes of attached devices
+ *
+ *	Note: Original code is ata_std_postreset().
+ */
+
+static void bfin_std_postreset (struct ata_port *ap, unsigned int *classes)
+{
+	unsigned long base = (unsigned long)ap->ioaddr.ctl_addr;
+
+	/* re-enable interrupts */
+	if (!ap->ops->error_handler)
+		ap->ops->irq_on(ap);

->error_handler is always non-NULL for this driver


+	/* is double-select really necessary? */
+	if (classes[0] != ATA_DEV_NONE)
+		ap->ops->dev_select(ap, 1);
+	if (classes[1] != ATA_DEV_NONE)
+		ap->ops->dev_select(ap, 0);
+
+	/* bail out if no device is present */
+	if (classes[0] == ATA_DEV_NONE && classes[1] == ATA_DEV_NONE) {
+		return;
+	}
+
+	/* set up device control */
+	write_atapi_register(base, ATA_REG_CTRL, ap->ctl);
+}
+
+/**
+ *	bfin_error_handler - Stock error handler for DMA controller
+ *	@ap: port to handle error for
+ */
+
+static void bfin_error_handler (struct ata_port *ap)
+{
+	ata_bmdma_drive_eh(ap, ata_std_prereset, bfin_std_softreset, NULL,
+			   bfin_std_postreset);
+}
+
+/**
+ *	bfin_bmdma_irq_clear - Clear ATAPI interrupt.
+ *	@ap: Port associated with this ATA transaction.
+ *
+ *	Note: Original code is ata_bmdma_irq_clear().
+ */
+
+static void bfin_bmdma_irq_clear (struct ata_port *ap)
+{
+	unsigned long base = (unsigned long)ap->ioaddr.ctl_addr;
+
+	pr_debug("in atapi irq clear\n");
+	ATAPI_SET_INT_STATUS(base, 0x1FF);
+}
+
+static void bfin_port_stop(struct ata_port *ap)
+{
+	pr_debug("in atapi port stop\n");
+	if (ap->udma_mask != 0 || ap->mwdma_mask != 0) {
+		free_dma(CH_ATAPI_RX);
+		free_dma(CH_ATAPI_TX);
+	}
+}
+
+static int bfin_port_start(struct ata_port *ap)
+{
+	pr_debug("in atapi port start\n");
+	if (ap->udma_mask != 0 || ap->mwdma_mask != 0) {

ditto above comments -- invert test, return early, un-indent code that follows


+		if (request_dma(CH_ATAPI_RX, "BFIN ATAPI RX DMA") >= 0) {
+			if (request_dma(CH_ATAPI_TX,
+				"BFIN ATAPI TX DMA") >= 0) {
+				return 0;
+			}
+			free_dma(CH_ATAPI_RX);
+		}
+		ap->udma_mask = 0;
+		ap->mwdma_mask = 0;
+		dev_err(ap->dev, "Unable to request ATAPI DMA!"
+			" Continue in PIO mode.\n");
+	}
+	return 0;
+}
+
+void bfin_qc_prep(struct ata_queued_cmd *qc)
+{
+}

use ata_noop_qc_prep() and delete the above


+static struct scsi_host_template bfin_sht = {
+	.module			= THIS_MODULE,
+	.name			= DRV_NAME,
+	.ioctl			= ata_scsi_ioctl,
+	.queuecommand		= ata_scsi_queuecmd,
+	.can_queue		= ATA_DEF_QUEUE,
+	.this_id		= ATA_SHT_THIS_ID,
+/*	.sg_tablesize		= LIBATA_MAX_PRD,*/
+	.sg_tablesize		= SG_NONE,
+	.cmd_per_lun		= ATA_SHT_CMD_PER_LUN,
+	.emulated		= ATA_SHT_EMULATED,
+	.use_clustering		= ATA_SHT_USE_CLUSTERING,
+	.proc_name		= DRV_NAME,
+	.dma_boundary		= ATA_DMA_BOUNDARY,
+	.slave_configure	= ata_scsi_slave_config,
+	.slave_destroy		= ata_scsi_slave_destroy,
+	.bios_param		= ata_std_bios_param,
+#ifdef CONFIG_PM
+	.resume			= ata_scsi_device_resume,
+	.suspend		= ata_scsi_device_suspend,
+#endif
+};
+
+static const struct ata_port_operations bfin_pata_ops = {
+	.port_disable		= ata_port_disable,
+	.set_piomode		= bfin_set_piomode,
+	.set_dmamode		= bfin_set_dmamode,
+
+	.tf_load		= bfin_tf_load,
+	.tf_read		= bfin_tf_read,
+	.exec_command		= bfin_exec_command,
+	.check_status		= bfin_check_status,
+	.check_altstatus	= bfin_check_altstatus,
+	.dev_select		= bfin_std_dev_select,
+
+	.bmdma_setup		= bfin_bmdma_setup,
+	.bmdma_start		= bfin_bmdma_start,
+	.bmdma_stop		= bfin_bmdma_stop,
+	.bmdma_status		= bfin_bmdma_status,
+	.data_xfer		= bfin_data_xfer,
+
+	.qc_prep		= bfin_qc_prep,
+	.qc_issue		= ata_qc_issue_prot,
+
+	.freeze			= bfin_bmdma_freeze,
+	.error_handler		= bfin_error_handler,
+	.post_internal_cmd	= bfin_bmdma_stop,
+
+	.irq_handler		= ata_interrupt,
+	.irq_clear		= bfin_bmdma_irq_clear,
+	.irq_on			= bfin_irq_on,
+	.irq_ack		= bfin_irq_ack,
+
+	.port_start		= bfin_port_start,
+	.port_stop		= bfin_port_stop,
+};
+
+static struct ata_port_info bfin_port_info[] = {
+	{
+		.sht		= &bfin_sht,
+		.flags		= ATA_FLAG_SLAVE_POSS
+				| ATA_FLAG_MMIO
+				| ATA_FLAG_NO_LEGACY,
+		.pio_mask	= 0x1f,	/* pio0-4 */
+		.mwdma_mask	= 0,
+#ifdef CONFIG_PATA_BF54X_DMA
+		.udma_mask	= ATA_UDMA5,
+#else
+		.udma_mask	= 0,
+#endif
+		.port_ops	= &bfin_pata_ops,
+	},
+};
+
+/**
+ *	bfin_reset_controller - initialize BF54x ATAPI controller.
+ */
+
+static int bfin_reset_controller(struct ata_host *host)
+{
+	unsigned long base = (unsigned long)host->ports[0]->ioaddr.ctl_addr;
+	int count;
+	unsigned short status;
+
+	/* Disable all ATAPI interrupts */
+	ATAPI_SET_INT_MASK(base, 0);
+	SSYNC();
+
+	/* Assert the RESET signal 25us*/
+	ATAPI_SET_CONTROL(base, ATAPI_GET_CONTROL(base) | DEV_RST);
+	udelay(30);
+
+	/* Negate the RESET signal for 2ms*/
+	ATAPI_SET_CONTROL(base, ATAPI_GET_CONTROL(base) & ~DEV_RST);
+	udelay(2100);

1) udelay() greater than 1000 should be mdelay()

2) you can sleep here, so msleep() is preferred


+	/* Wait on Busy flag to clear */
+	count = 10000000;
+	do {
+		status = read_atapi_register(base, ATA_REG_STATUS);
+	} while (count-- && (status & ATA_BUSY));
+
+	/* Enable only ATAPI Device interrupt */
+	ATAPI_SET_INT_MASK(base, 1);
+	SSYNC();
+
+	return (!count);
+}
+
+/**
+ *	atapi_io_port - define atapi peripheral port pins.
+ */
+static unsigned short atapi_io_port[] = {
+	P_ATAPI_RESET,
+	P_ATAPI_DIOR,
+	P_ATAPI_DIOW,
+	P_ATAPI_CS0,
+	P_ATAPI_CS1,
+	P_ATAPI_DMACK,
+	P_ATAPI_DMARQ,
+	P_ATAPI_INTRQ,
+	P_ATAPI_IORDY,
+	0
+};
+
+/**
+ *	bfin_atapi_probe	-	attach a bfin atapi interface
+ *	@pdev: platform device
+ *
+ *	Register a bfin atapi interface.
+ *
+ *
+ *	Platform devices are expected to contain 2 resources per port:
+ *
+ *		- I/O Base (IORESOURCE_IO)
+ *		- IRQ	   (IORESOURCE_IRQ)
+ *
+ */
+static int __devinit bfin_atapi_probe(struct platform_device *pdev)
+{
+	int board_idx = 0;
+	struct resource *res;
+	struct ata_host *host;
+	const struct ata_port_info *ppi[] =
+		{ &bfin_port_info[board_idx], NULL };
+
+	/*
+	 * Simple resource validation ..
+	 */
+	if (unlikely(pdev->num_resources != 2)) {
+		dev_err(&pdev->dev, "invalid number of resources\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Get the register base first
+	 */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (res == NULL)
+		return -EINVAL;
+
+	/*
+	 * Now that that's out of the way, wire up the port..
+	 */
+	host = ata_host_alloc_pinfo(&pdev->dev, ppi, 1);
+	if (!host)
+		return -ENOMEM;
+
+	host->ports[0]->ioaddr.ctl_addr = (void *)res->start;
+
+	if (peripheral_request_list(atapi_io_port, "atapi-io-port")) {
+		dev_err(&pdev->dev, "Requesting Peripherals faild\n");
+		return -EFAULT;
+	}
+
+	if (bfin_reset_controller(host)) {
+		peripheral_free_list(atapi_io_port);
+		dev_err(&pdev->dev, "Fail to reset ATAPI device\n");
+		return -EFAULT;
+	}
+
+	if (ata_host_activate(host, platform_get_irq(pdev, 0),
+		ata_interrupt, IRQF_SHARED, &bfin_sht) != 0) {
+		peripheral_free_list(atapi_io_port);
+		dev_err(&pdev->dev, "Fail to attach ATAPI device\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/**
+ *	bfin_atapi_remove	-	unplug a bfin atapi interface
+ *	@pdev: platform device
+ *
+ *	A bfin atapi device has been unplugged. Perform the needed
+ *	cleanup. Also called on module unload for any active devices.
+ */
+static int __devexit bfin_atapi_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ata_host *host = dev_get_drvdata(dev);
+
+	ata_host_detach(host);
+
+	peripheral_free_list(atapi_io_port);
+
+	return 0;
+}
+
+static struct platform_driver bfin_atapi_driver = {
+	.probe			= bfin_atapi_probe,
+	.remove			= __devexit_p(bfin_atapi_remove),
+	.driver = {
+		.name		= DRV_NAME,
+		.owner		= THIS_MODULE,
+	},

if you are going to implement suspend/resume in scsi-host-template, you probably should do so here too


+static int __init bfin_atapi_init (void)
+{
+	pr_info("register bfin atapi driver\n");
+	return platform_driver_register(&bfin_atapi_driver);
+}
+
+static void __exit bfin_atapi_exit (void)
+{
+	platform_driver_unregister(&bfin_atapi_driver);
+}
+
+module_init(bfin_atapi_init);
+module_exit(bfin_atapi_exit);
+
+MODULE_AUTHOR("Sonic Zhang <[email protected]>");
+MODULE_DESCRIPTION("ATAPI libata driver for blackfin 54x ATAPI controller");

recommend s/ATAPI/PATA/


+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);



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