[ARM] pata_pxa: DMA-capable PATA driver

This patch adds a driver for a harddrive attached to PXA address and data bus.
Unlike pata_platform, this driver allows usage of PXA DMA controller, making the
transmission speed 3x higher.
Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>

arch/arm/mach-pxa/include/mach/pata_pxa.h

+/*
+ * Generic PXA PATA driver
+ *
+ * Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2, or (at your option)
+ *  any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef	__MACH_PATA_PXA_H__
+#define	__MACH_PATA_PXA_H__
+
+struct pata_pxa_pdata {
+	/* PXA DMA DREQ<0:2> pin */
+	uint32_t	dma_dreq;
+	/* Register shift */
+	uint32_t	reg_shift;
+	/* IRQ flags */
+	uint32_t	irq_flags;
+};
+
+#endif	/* __MACH_PATA_PXA_H__ */

drivers/ata/Kconfig

@@ -642,6 +642,17 @@ config PATA_VIA
 
 	  If unsure, say N.
 
+config PATA_PXA
+	tristate "PXA DMA-capable PATA support"
+	depends on ARCH_PXA
+	help
+	  This option enables support for harddrive attached to PXA CPU's bus.
+
+	  NOTE: This driver utilizes PXA DMA controller, in case your hardware
+	        is not capable of doing MWDMA, use pata_platform instead.
+
+	  If unsure, say N.
+
 config PATA_WINBOND
 	tristate "Winbond SL82C105 PATA support"
 	depends on PCI

drivers/ata/Makefile

@@ -89,6 +89,8 @@ obj-$(CONFIG_PATA_RB532)	+= pata_rb532_cf.o
 obj-$(CONFIG_PATA_RZ1000)	+= pata_rz1000.o
 obj-$(CONFIG_PATA_WINBOND_VLB)	+= pata_winbond.o
 
+obj-$(CONFIG_PATA_PXA)		+= pata_pxa.o
+
 # Should be last but two libata driver
 obj-$(CONFIG_PATA_ACPI)		+= pata_acpi.o
 # Should be last but one libata driver

drivers/ata/pata_pxa.c

+/*
+ * Generic PXA PATA driver
+ *
+ * Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2, or (at your option)
+ *  any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; see the file COPYING.  If not, write to
+ *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/ata.h>
+#include <linux/libata.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/slab.h>
+#include <linux/completion.h>
+
+#include <scsi/scsi_host.h>
+
+#include <mach/pxa2xx-regs.h>
+#include <mach/pata_pxa.h>
+#include <mach/dma.h>
+
+#define DRV_NAME	"pata_pxa"
+#define DRV_VERSION	"0.1"
+
+struct pata_pxa_data {
+	uint32_t		dma_channel;
+	struct pxa_dma_desc	*dma_desc;
+	dma_addr_t		dma_desc_addr;
+	uint32_t		dma_desc_id;
+
+	/* DMA IO physical address */
+	uint32_t		dma_io_addr;
+	/* PXA DREQ<0:2> pin selector */
+	uint32_t		dma_dreq;
+	/* DMA DCSR register value */
+	uint32_t		dma_dcsr;
+
+	struct completion	dma_done;
+};
+
+/*
+ * Setup the DMA descriptors. The size is transfer capped at 4k per descriptor,
+ * if the transfer is longer, it is split into multiple chained descriptors.
+ */
+static void pxa_load_dmac(struct scatterlist *sg, struct ata_queued_cmd *qc)
+{
+	struct pata_pxa_data *pd = qc->ap->private_data;
+
+	uint32_t cpu_len, seg_len;
+	dma_addr_t cpu_addr;
+
+	cpu_addr = sg_dma_address(sg);
+	cpu_len = sg_dma_len(sg);
+
+	do {
+		seg_len = (cpu_len > 0x1000) ? 0x1000 : cpu_len;
+
+		pd->dma_desc[pd->dma_desc_id].ddadr = pd->dma_desc_addr +
+			((pd->dma_desc_id + 1) * sizeof(struct pxa_dma_desc));
+
+		pd->dma_desc[pd->dma_desc_id].dcmd = DCMD_BURST32 |
+					DCMD_WIDTH2 | (DCMD_LENGTH & seg_len);
+
+		if (qc->tf.flags & ATA_TFLAG_WRITE) {
+			pd->dma_desc[pd->dma_desc_id].dsadr = cpu_addr;
+			pd->dma_desc[pd->dma_desc_id].dtadr = pd->dma_io_addr;
+			pd->dma_desc[pd->dma_desc_id].dcmd |= DCMD_INCSRCADDR |
+						DCMD_FLOWTRG;
+		} else {
+			pd->dma_desc[pd->dma_desc_id].dsadr = pd->dma_io_addr;
+			pd->dma_desc[pd->dma_desc_id].dtadr = cpu_addr;
+			pd->dma_desc[pd->dma_desc_id].dcmd |= DCMD_INCTRGADDR |
+						DCMD_FLOWSRC;
+		}
+
+		cpu_len -= seg_len;
+		cpu_addr += seg_len;
+		pd->dma_desc_id++;
+
+	} while (cpu_len);
+
+	/* Should not happen */
+	if (seg_len & 0x1f)
+		DALGN |= (1 << pd->dma_dreq);
+}
+
+/*
+ * Prepare taskfile for submission.
+ */
+static void pxa_qc_prep(struct ata_queued_cmd *qc)
+{
+	struct pata_pxa_data *pd = qc->ap->private_data;
+	int si = 0;
+	struct scatterlist *sg;
+
+	if (!(qc->flags & ATA_QCFLAG_DMAMAP))
+		return;
+
+	pd->dma_desc_id = 0;
+
+	DCSR(pd->dma_channel) = 0;
+	DALGN &= ~(1 << pd->dma_dreq);
+
+	for_each_sg(qc->sg, sg, qc->n_elem, si)
+		pxa_load_dmac(sg, qc);
+
+	pd->dma_desc[pd->dma_desc_id - 1].ddadr = DDADR_STOP;
+
+	/* Fire IRQ only at the end of last block */
+	pd->dma_desc[pd->dma_desc_id - 1].dcmd |= DCMD_ENDIRQEN;
+
+	DDADR(pd->dma_channel) = pd->dma_desc_addr;
+	DRCMR(pd->dma_dreq) = DRCMR_MAPVLD | pd->dma_channel;
+
+}
+
+/*
+ * Configure the DMA controller, load the DMA descriptors, but don't start the
+ * DMA controller yet. Only issue the ATA command.
+ */
+static void pxa_bmdma_setup(struct ata_queued_cmd *qc)
+{
+	qc->ap->ops->sff_exec_command(qc->ap, &qc->tf);
+}
+
+/*
+ * Execute the DMA transfer.
+ */
+static void pxa_bmdma_start(struct ata_queued_cmd *qc)
+{
+	struct pata_pxa_data *pd = qc->ap->private_data;
+	init_completion(&pd->dma_done);
+	DCSR(pd->dma_channel) = DCSR_RUN;
+}
+
+/*
+ * Wait until the DMA transfer completes, then stop the DMA controller.
+ */
+static void pxa_bmdma_stop(struct ata_queued_cmd *qc)
+{
+	struct pata_pxa_data *pd = qc->ap->private_data;
+
+	if ((DCSR(pd->dma_channel) & DCSR_RUN) &&
+		wait_for_completion_timeout(&pd->dma_done, HZ))
+		dev_err(qc->ap->dev, "Timeout waiting for DMA completion!");
+
+	DCSR(pd->dma_channel) = 0;
+}
+
+/*
+ * Read DMA status. The bmdma_stop() will take care of properly finishing the
+ * DMA transfer so we always have DMA-complete interrupt here.
+ */
+static unsigned char pxa_bmdma_status(struct ata_port *ap)
+{
+	struct pata_pxa_data *pd = ap->private_data;
+	unsigned char ret = ATA_DMA_INTR;
+
+	if (pd->dma_dcsr & DCSR_BUSERR)
+		ret |= ATA_DMA_ERR;
+
+	return ret;
+}
+
+/*
+ * No IRQ register present so we do nothing.
+ */
+static void pxa_irq_clear(struct ata_port *ap)
+{
+}
+
+/*
+ * Check for ATAPI DMA. ATAPI DMA is unsupported by this driver. It's still
+ * unclear why ATAPI has DMA issues.
+ */
+static int pxa_check_atapi_dma(struct ata_queued_cmd *qc)
+{
+	return -EOPNOTSUPP;
+}
+
+static struct scsi_host_template pxa_ata_sht = {
+	ATA_BMDMA_SHT(DRV_NAME),
+};
+
+static struct ata_port_operations pxa_ata_port_ops = {
+	.inherits		= &ata_bmdma_port_ops,
+	.cable_detect		= ata_cable_40wire,
+
+	.bmdma_setup		= pxa_bmdma_setup,
+	.bmdma_start		= pxa_bmdma_start,
+	.bmdma_stop		= pxa_bmdma_stop,
+	.bmdma_status		= pxa_bmdma_status,
+
+	.check_atapi_dma	= pxa_check_atapi_dma,
+
+	.sff_irq_clear		= pxa_irq_clear,
+
+	.qc_prep		= pxa_qc_prep,
+};
+
+/*
+ * DMA interrupt handler.
+ */
+static void pxa_ata_dma_irq(int dma, void *port)
+{
+	struct ata_port *ap = port;
+	struct pata_pxa_data *pd = ap->private_data;
+
+	pd->dma_dcsr = DCSR(dma);
+	DCSR(dma) = pd->dma_dcsr;
+
+	if (pd->dma_dcsr & DCSR_STOPSTATE)
+		complete(&pd->dma_done);
+}
+
+static int __devinit pxa_ata_probe(struct platform_device *pdev)
+{
+	struct ata_host *host;
+	struct ata_port *ap;
+	struct pata_pxa_data *data;
+	struct resource *cmd_res;
+	struct resource *ctl_res;
+	struct resource *dma_res;
+	struct resource *irq_res;
+	struct pata_pxa_pdata *pdata = pdev->dev.platform_data;
+	int ret = 0;
+
+	/*
+	 * Resource validation, three resources are needed:
+	 *  - CMD port base address
+	 *  - CTL port base address
+	 *  - DMA port base address
+	 *  - IRQ pin
+	 */
+	if (pdev->num_resources != 4) {
+		dev_err(&pdev->dev, "invalid number of resources\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * CMD port base address
+	 */
+	cmd_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (unlikely(cmd_res == NULL))
+		return -EINVAL;
+
+	/*
+	 * CTL port base address
+	 */
+	ctl_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (unlikely(ctl_res == NULL))
+		return -EINVAL;
+
+	/*
+	 * DMA port base address
+	 */
+	dma_res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
+	if (unlikely(dma_res == NULL))
+		return -EINVAL;
+
+	/*
+	 * IRQ pin
+	 */
+	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (unlikely(irq_res == NULL))
+		return -EINVAL;
+
+	/*
+	 * Allocate the host
+	 */
+	host = ata_host_alloc(&pdev->dev, 1);
+	if (!host)
+		return -ENOMEM;
+
+	ap		= host->ports[0];
+	ap->ops		= &pxa_ata_port_ops;
+	ap->pio_mask	= ATA_PIO4;
+	ap->mwdma_mask	= ATA_MWDMA2;
+	ap->flags	= ATA_FLAG_MMIO;
+
+	ap->ioaddr.cmd_addr	= devm_ioremap(&pdev->dev, cmd_res->start,
+						resource_size(cmd_res));
+	ap->ioaddr.ctl_addr	= devm_ioremap(&pdev->dev, ctl_res->start,
+						resource_size(ctl_res));
+	ap->ioaddr.bmdma_addr	= devm_ioremap(&pdev->dev, dma_res->start,
+						resource_size(dma_res));
+
+	/*
+	 * Adjust register offsets
+	 */
+	ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
+	ap->ioaddr.data_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_DATA << pdata->reg_shift);
+	ap->ioaddr.error_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_ERR << pdata->reg_shift);
+	ap->ioaddr.feature_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_FEATURE << pdata->reg_shift);
+	ap->ioaddr.nsect_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_NSECT << pdata->reg_shift);
+	ap->ioaddr.lbal_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_LBAL << pdata->reg_shift);
+	ap->ioaddr.lbam_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_LBAM << pdata->reg_shift);
+	ap->ioaddr.lbah_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_LBAH << pdata->reg_shift);
+	ap->ioaddr.device_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_DEVICE << pdata->reg_shift);
+	ap->ioaddr.status_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_STATUS << pdata->reg_shift);
+	ap->ioaddr.command_addr	= ap->ioaddr.cmd_addr +
+					(ATA_REG_CMD << pdata->reg_shift);
+
+	/*
+	 * Allocate and load driver's internal data structure
+	 */
+	data = devm_kzalloc(&pdev->dev, sizeof(struct pata_pxa_data),
+								GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ap->private_data = data;
+	data->dma_dreq = pdata->dma_dreq;
+	data->dma_io_addr = dma_res->start;
+
+	/*
+	 * Allocate space for the DMA descriptors
+	 */
+	data->dma_desc = dmam_alloc_coherent(&pdev->dev, PAGE_SIZE,
+					&data->dma_desc_addr, GFP_KERNEL);
+	if (!data->dma_desc)
+		return -EINVAL;
+
+	/*
+	 * Request the DMA channel
+	 */
+	data->dma_channel = pxa_request_dma(DRV_NAME, DMA_PRIO_LOW,
+						pxa_ata_dma_irq, ap);
+	if (data->dma_channel < 0)
+		return -EBUSY;
+
+	/*
+	 * Stop and clear the DMA channel
+	 */
+	DCSR(data->dma_channel) = 0;
+
+	/*
+	 * Activate the ATA host
+	 */
+	ret = ata_host_activate(host, irq_res->start, ata_sff_interrupt,
+				pdata->irq_flags, &pxa_ata_sht);
+	if (ret)
+		pxa_free_dma(data->dma_channel);
+
+	return ret;
+}
+
+static int __devexit pxa_ata_remove(struct platform_device *pdev)
+{
+	struct ata_host *host = dev_get_drvdata(&pdev->dev);
+	struct pata_pxa_data *data = host->ports[0]->private_data;
+
+	pxa_free_dma(data->dma_channel);
+
+	ata_host_detach(host);
+
+	return 0;
+}
+
+static struct platform_driver pxa_ata_driver = {
+	.probe		= pxa_ata_probe,
+	.remove		= __devexit_p(pxa_ata_remove),
+	.driver		= {
+		.name		= DRV_NAME,
+		.owner		= THIS_MODULE,
+	},
+};
+
+static int __init pxa_ata_init(void)
+{
+	return platform_driver_register(&pxa_ata_driver);
+}
+
+static void __exit pxa_ata_exit(void)
+{
+	platform_driver_unregister(&pxa_ata_driver);
+}
+
+module_init(pxa_ata_init);
+module_exit(pxa_ata_exit);
+
+MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
+MODULE_DESCRIPTION("DMA-capable driver for PATA on PXA CPU");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("platform:" DRV_NAME);