pata_cs5536: ATA driver for Geode companion chip

This is a driver for the ATA controller on the Geode CS5536 companion
chip.  The PCI device ID for this device was previously claimed by
pata_amd.c but the PIO timings were not correct.  This driver also
works around a bug in some BIOSes that handle unaligned access to the
PCI config registers poorly.  Finally, the driver allows fallback to
using MSR registers for configuration on BIOSes that are truly
broken.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/Kconfig

@@ -272,6 +272,15 @@ config PATA_CS5535
 
 	  If unsure, say N.
 
+config PATA_CS5536
+	tristate "CS5536 PATA support (Experimental)"
+	depends on PCI && X86 && !X86_64 && EXPERIMENTAL
+	help
+	  This option enables support for the AMD CS5536
+	  companion chip used with the Geode LX processor family.
+
+	  If unsure, say N.
+
 config PATA_CYPRESS
 	tristate "Cypress CY82C693 PATA support (Very Experimental)"
 	depends on PCI && EXPERIMENTAL

drivers/ata/Makefile

@@ -28,6 +28,7 @@ obj-$(CONFIG_PATA_CMD64X)	+= pata_cmd64x.o
 obj-$(CONFIG_PATA_CS5520)	+= pata_cs5520.o
 obj-$(CONFIG_PATA_CS5530)	+= pata_cs5530.o
 obj-$(CONFIG_PATA_CS5535)	+= pata_cs5535.o
+obj-$(CONFIG_PATA_CS5536)	+= pata_cs5536.o
 obj-$(CONFIG_PATA_CYPRESS)	+= pata_cypress.o
 obj-$(CONFIG_PATA_EFAR)		+= pata_efar.o
 obj-$(CONFIG_PATA_HPT366)	+= pata_hpt366.o

drivers/ata/pata_cs5536.c

@@ -0,0 +1,346 @@
+/*
+ * pata_cs5536.c	- CS5536 PATA for new ATA layer
+ *			  (C) 2007 Martin K. Petersen <mkp@mkp.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307	 USA
+ *
+ * Documentation:
+ *	Available from AMD web site.
+ *
+ * The IDE timing registers for the CS5536 live in the Geode Machine
+ * Specific Register file and not PCI config space.  Most BIOSes
+ * virtualize the PCI registers so the chip looks like a standard IDE
+ * controller.	Unfortunately not all implementations get this right.
+ * In particular some have problems with unaligned accesses to the
+ * virtualized PCI registers.  This driver always does full dword
+ * writes to work around the issue.  Also, in case of a bad BIOS this
+ * driver can be loaded with the "msr=1" parameter which forces using
+ * the Machine Specific Registers to configure the device.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/libata.h>
+#include <scsi/scsi_host.h>
+#include <asm/msr.h>
+
+#define DRV_NAME	"pata_cs5536"
+#define DRV_VERSION	"0.0.5"
+
+enum {
+	CFG			= 0,
+	DTC			= 1,
+	CAST			= 2,
+	ETC			= 3,
+
+	MSR_IDE_BASE		= 0x51300000,
+	MSR_IDE_CFG		= (MSR_IDE_BASE + 0x10),
+	MSR_IDE_DTC		= (MSR_IDE_BASE + 0x12),
+	MSR_IDE_CAST		= (MSR_IDE_BASE + 0x13),
+	MSR_IDE_ETC		= (MSR_IDE_BASE + 0x14),
+
+	PCI_IDE_CFG		= 0x40,
+	PCI_IDE_DTC		= 0x48,
+	PCI_IDE_CAST		= 0x4c,
+	PCI_IDE_ETC		= 0x50,
+
+	IDE_CFG_CHANEN		= 0x2,
+	IDE_CFG_CABLE		= 0x10000,
+
+	IDE_D0_SHIFT		= 24,
+	IDE_D1_SHIFT		= 16,
+	IDE_DRV_MASK		= 0xff,
+
+	IDE_CAST_D0_SHIFT	= 6,
+	IDE_CAST_D1_SHIFT	= 4,
+	IDE_CAST_DRV_MASK	= 0x3,
+	IDE_CAST_CMD_MASK	= 0xff,
+	IDE_CAST_CMD_SHIFT	= 24,
+
+	IDE_ETC_NODMA		= 0x03,
+};
+
+static int use_msr;
+
+static const u32 msr_reg[4] = {
+	MSR_IDE_CFG, MSR_IDE_DTC, MSR_IDE_CAST, MSR_IDE_ETC,
+};
+
+static const u8 pci_reg[4] = {
+	PCI_IDE_CFG, PCI_IDE_DTC, PCI_IDE_CAST, PCI_IDE_ETC,
+};
+
+static inline int cs5536_read(struct pci_dev *pdev, int reg, int *val)
+{
+	if (unlikely(use_msr)) {
+		u32 dummy;
+
+		rdmsr(msr_reg[reg], *val, dummy);
+		return 0;
+	}
+
+	return pci_read_config_dword(pdev, pci_reg[reg], val);
+}
+
+static inline int cs5536_write(struct pci_dev *pdev, int reg, int val)
+{
+	if (unlikely(use_msr)) {
+		wrmsr(msr_reg[reg], val, 0);
+		return 0;
+	}
+
+	return pci_write_config_dword(pdev, pci_reg[reg], val);
+}
+
+/**
+ *	cs5536_cable_detect	-	detect cable type
+ *	@ap: Port to detect on
+ *	@deadline: deadline jiffies for the operation
+ *
+ *	Perform cable detection for ATA66 capable cable. Return a libata
+ *	cable type.
+ */
+
+static int cs5536_cable_detect(struct ata_port *ap)
+{
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u32 cfg;
+
+	cs5536_read(pdev, CFG, &cfg);
+
+	if (cfg & (IDE_CFG_CABLE << ap->port_no))
+		return ATA_CBL_PATA80;
+	else
+		return ATA_CBL_PATA40;
+}
+
+/**
+ *	cs5536_set_piomode		-	PIO setup
+ *	@ap: ATA interface
+ *	@adev: device on the interface
+ */
+
+static void cs5536_set_piomode(struct ata_port *ap, struct ata_device *adev)
+{
+	static const u8 drv_timings[5] = {
+		0x98, 0x55, 0x32, 0x21, 0x20,
+	};
+
+	static const u8 addr_timings[5] = {
+		0x2, 0x1, 0x0, 0x0, 0x0,
+	};
+
+	static const u8 cmd_timings[5] = {
+		0x99, 0x92, 0x90, 0x22, 0x20,
+	};
+
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	struct ata_device *pair = ata_dev_pair(adev);
+	int mode = adev->pio_mode - XFER_PIO_0;
+	int cmdmode = mode;
+	int dshift = ap->port_no ? IDE_D1_SHIFT : IDE_D0_SHIFT;
+	int cshift = ap->port_no ? IDE_CAST_D1_SHIFT : IDE_CAST_D0_SHIFT;
+	u32 dtc, cast, etc;
+
+	if (pair)
+		cmdmode = min(mode, pair->pio_mode - XFER_PIO_0);
+
+	cs5536_read(pdev, DTC, &dtc);
+	cs5536_read(pdev, CAST, &cast);
+	cs5536_read(pdev, ETC, &etc);
+
+	dtc &= ~(IDE_DRV_MASK << dshift);
+	dtc |= drv_timings[mode] << dshift;
+
+	cast &= ~(IDE_CAST_DRV_MASK << cshift);
+	cast |= addr_timings[mode] << cshift;
+
+	cast &= ~(IDE_CAST_CMD_MASK << IDE_CAST_CMD_SHIFT);
+	cast |= cmd_timings[cmdmode] << IDE_CAST_CMD_SHIFT;
+
+	etc &= ~(IDE_DRV_MASK << dshift);
+	etc |= IDE_ETC_NODMA << dshift;
+
+	cs5536_write(pdev, DTC, dtc);
+	cs5536_write(pdev, CAST, cast);
+	cs5536_write(pdev, ETC, etc);
+}
+
+/**
+ *	cs5536_set_dmamode		-	DMA timing setup
+ *	@ap: ATA interface
+ *	@adev: Device being configured
+ *
+ */
+
+static void cs5536_set_dmamode(struct ata_port *ap, struct ata_device *adev)
+{
+	static const u8 udma_timings[6] = {
+		0xc2, 0xc1, 0xc0, 0xc4, 0xc5, 0xc6,
+	};
+
+	static const u8 mwdma_timings[3] = {
+		0x67, 0x21, 0x20,
+	};
+
+	struct pci_dev *pdev = to_pci_dev(ap->host->dev);
+	u32 dtc, etc;
+	int mode = adev->dma_mode;
+	int dshift = ap->port_no ? IDE_D1_SHIFT : IDE_D0_SHIFT;
+
+	if (mode >= XFER_UDMA_0) {
+		cs5536_read(pdev, ETC, &etc);
+
+		etc &= ~(IDE_DRV_MASK << dshift);
+		etc |= udma_timings[mode - XFER_UDMA_0] << dshift;
+
+		cs5536_write(pdev, ETC, etc);
+	} else { /* MWDMA */
+		cs5536_read(pdev, DTC, &dtc);
+
+		dtc &= ~(IDE_DRV_MASK << dshift);
+		dtc |= mwdma_timings[mode] << dshift;
+
+		cs5536_write(pdev, DTC, dtc);
+	}
+}
+
+static struct scsi_host_template cs5536_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,
+	.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,
+};
+
+static struct ata_port_operations cs5536_port_ops = {
+	.port_disable		= ata_port_disable,
+	.set_piomode		= cs5536_set_piomode,
+	.set_dmamode		= cs5536_set_dmamode,
+	.mode_filter		= ata_pci_default_filter,
+
+	.tf_load		= ata_tf_load,
+	.tf_read		= ata_tf_read,
+	.check_status		= ata_check_status,
+	.exec_command		= ata_exec_command,
+	.dev_select		= ata_std_dev_select,
+
+	.freeze			= ata_bmdma_freeze,
+	.thaw			= ata_bmdma_thaw,
+	.error_handler		= ata_bmdma_error_handler,
+	.post_internal_cmd	= ata_bmdma_post_internal_cmd,
+	.cable_detect		= cs5536_cable_detect,
+
+	.bmdma_setup		= ata_bmdma_setup,
+	.bmdma_start		= ata_bmdma_start,
+	.bmdma_stop		= ata_bmdma_stop,
+	.bmdma_status		= ata_bmdma_status,
+
+	.qc_prep		= ata_qc_prep,
+	.qc_issue		= ata_qc_issue_prot,
+
+	.data_xfer		= ata_data_xfer,
+
+	.irq_handler		= ata_interrupt,
+	.irq_clear		= ata_bmdma_irq_clear,
+	.irq_on			= ata_irq_on,
+	.irq_ack		= ata_irq_ack,
+
+	.port_start		= ata_port_start,
+};
+
+/**
+ *	cs5536_init_one
+ *	@dev: PCI device
+ *	@id: Entry in match table
+ *
+ */
+
+static int cs5536_init_one(struct pci_dev *dev, const struct pci_device_id *id)
+{
+	static const struct ata_port_info info = {
+		.sht = &cs5536_sht,
+		.flags = ATA_FLAG_SLAVE_POSS,
+		.pio_mask = 0x1f,
+		.mwdma_mask = 0x07,
+		.udma_mask = ATA_UDMA5,
+		.port_ops = &cs5536_port_ops,
+	};
+
+	const struct ata_port_info *ppi[] = { &info, &ata_dummy_port_info };
+	u32 cfg;
+
+	if (use_msr)
+		printk(KERN_ERR DRV_NAME ": Using MSR regs instead of PCI\n");
+
+	cs5536_read(dev, CFG, &cfg);
+
+	if ((cfg & IDE_CFG_CHANEN) == 0) {
+		printk(KERN_ERR DRV_NAME ": disabled by BIOS\n");
+		return -ENODEV;
+	}
+
+	return ata_pci_init_one(dev, ppi);
+}
+
+static const struct pci_device_id cs5536[] = {
+	{ PCI_VDEVICE(AMD,	PCI_DEVICE_ID_AMD_CS5536_IDE), },
+	{ },
+};
+
+static struct pci_driver cs5536_pci_driver = {
+	.name		= DRV_NAME,
+	.id_table	= cs5536,
+	.probe		= cs5536_init_one,
+	.remove		= ata_pci_remove_one,
+#ifdef CONFIG_PM
+	.suspend	= ata_pci_device_suspend,
+	.resume		= ata_pci_device_resume,
+#endif
+};
+
+static int __init cs5536_init(void)
+{
+	return pci_register_driver(&cs5536_pci_driver);
+}
+
+static void __exit cs5536_exit(void)
+{
+	pci_unregister_driver(&cs5536_pci_driver);
+}
+
+MODULE_AUTHOR("Martin K. Petersen");
+MODULE_DESCRIPTION("low-level driver for the CS5536 IDE controller");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, cs5536);
+MODULE_VERSION(DRV_VERSION);
+module_param_named(msr, use_msr, int, 0644);
+MODULE_PARM_DESC(msr, "Force using MSR to configure IDE function (Default: 0)");
+
+module_init(cs5536_init);
+module_exit(cs5536_exit);