[PATCH] PXA DMA-capable PATA driver
Marek Vasut
marek.vasut at gmail.com
Sun May 9 23:02:05 EDT 2010
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 at gmail.com>
---
arch/arm/mach-pxa/include/mach/pata_pxa.h | 33 +++
drivers/ata/Kconfig | 11 +
drivers/ata/Makefile | 1 +
drivers/ata/pata_pxa.c | 383 +++++++++++++++++++++++++++++
4 files changed, 428 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/mach-pxa/include/mach/pata_pxa.h
create mode 100644 drivers/ata/pata_pxa.c
diff --git a/arch/arm/mach-pxa/include/mach/pata_pxa.h b/arch/arm/mach-pxa/include/mach/pata_pxa.h
new file mode 100644
index 0000000..6cf7df1
--- /dev/null
+++ b/arch/arm/mach-pxa/include/mach/pata_pxa.h
@@ -0,0 +1,33 @@
+/*
+ * Generic PXA PATA driver
+ *
+ * Copyright (C) 2010 Marek Vasut <marek.vasut at 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__ */
diff --git a/drivers/ata/Kconfig b/drivers/ata/Kconfig
index 01c52c4..5cd3e8c 100644
--- a/drivers/ata/Kconfig
+++ b/drivers/ata/Kconfig
@@ -684,6 +684,17 @@ 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
diff --git a/drivers/ata/Makefile b/drivers/ata/Makefile
index fc936d4..5ecf45a 100644
--- a/drivers/ata/Makefile
+++ b/drivers/ata/Makefile
@@ -79,6 +79,7 @@ obj-$(CONFIG_PATA_PLATFORM) += pata_platform.o
obj-$(CONFIG_PATA_AT91) += pata_at91.o
obj-$(CONFIG_PATA_OF_PLATFORM) += pata_of_platform.o
obj-$(CONFIG_PATA_ICSIDE) += pata_icside.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
diff --git a/drivers/ata/pata_pxa.c b/drivers/ata/pata_pxa.c
new file mode 100644
index 0000000..66ab1ac
--- /dev/null
+++ b/drivers/ata/pata_pxa.c
@@ -0,0 +1,383 @@
+/*
+ * Generic PXA PATA driver
+ *
+ * Copyright (C) 2010 Marek Vasut <marek.vasut at 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;
+
+ 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);
+}
+
+/*
+ * 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)
+{
+ struct pata_pxa_data *pd = qc->ap->private_data;
+ int si = 0;
+ struct scatterlist *sg;
+
+ 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;
+ 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)
+ if (wait_for_completion_timeout(&pd->dma_done, HZ))
+ BUG();
+
+ 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)
+{
+ return ATA_DMA_INTR;
+}
+
+/*
+ * 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,
+};
+
+/*
+ * DMA interrupt handler.
+ */
+static void pxa_ata_dma_irq(int dma, void *port)
+{
+ uint32_t dcsr;
+ struct ata_port *ap = port;
+ struct pata_pxa_data *pd = ap->private_data;
+
+ dcsr = DCSR(dma);
+ DCSR(dma) = dcsr;
+ if (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;
+
+ /*
+ * 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;
+
+ /*
+ * 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;
+
+ /*
+ * Allocate space for the DMA descriptors
+ */
+ data->dma_desc = dmam_alloc_coherent(&pdev->dev, PAGE_SIZE,
+ &data->dma_desc_addr, GFP_KERNEL);
+
+ /*
+ * Activate the ATA host
+ */
+ return ata_host_activate(host, irq_res->start, ata_sff_interrupt,
+ pdata->irq_flags, &pxa_ata_sht);
+}
+
+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 at gmail.com>");
+MODULE_DESCRIPTION("DMA-capable driver for PATA on PXA CPU");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_VERSION);
+MODULE_ALIAS("platform:" DRV_NAME);
--
1.7.0
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