linux/drivers/ata/ahci_platform.c
Tejun Heo 6b7ae9545a libata: reimplement link power management
The current LPM implementation has the following issues.

* Operation order isn't well thought-out.  e.g. HIPM should be
  configured after IPM in SControl is properly configured.  Not the
  other way around.

* Suspend/resume paths call ata_lpm_enable/disable() which must only
  be called from EH context directly.  Also, ata_lpm_enable/disable()
  were called whether LPM was in use or not.

* Implementation is per-port when it should be per-link.  As a result,
  it can't be used for controllers with slave links or PMP.

* LPM state isn't managed consistently.  After a link reset for
  whatever reason including suspend/resume the actual LPM state would
  be reset leaving ap->lpm_policy inconsistent.

* Generic/driver-specific logic boundary isn't clear.  Currently,
  libahci has to mangle stuff which libata EH proper should be
  handling.  This makes the implementation unnecessarily complex and
  fragile.

* Tied to ALPM.  Doesn't consider DIPM only cases and doesn't check
  whether the device allows HIPM.

* Error handling isn't implemented.

Given the extent of mismatch with the rest of libata, I don't think
trying to fix it piecewise makes much sense.  This patch reimplements
LPM support.

* The new implementation is per-link.  The target policy is still
  port-wide (ap->target_lpm_policy) but all the mechanisms and states
  are per-link and integrate well with the rest of link abstraction
  and can work with slave and PMP links.

* Core EH has proper control of LPM state.  LPM state is reconfigured
  when and only when reconfiguration is necessary.  It makes sure that
  LPM state is reset when probing for new device on the link.
  Controller agnostic logic is now implemented in libata EH proper and
  driver implementation only has to deal with controller specifics.

* Proper error handling.  LPM config failure is attributed to the
  device on the link and LPM is disabled for the link if it fails
  repeatedly.

* ops->enable/disable_pm() are replaced with single ops->set_lpm()
  which takes @policy and @hints.  This simplifies driver specific
  implementation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2010-10-21 20:21:04 -04:00

197 lines
4.6 KiB
C

/*
* AHCI SATA platform driver
*
* Copyright 2004-2005 Red Hat, Inc.
* Jeff Garzik <jgarzik@pobox.com>
* Copyright 2010 MontaVista Software, LLC.
* Anton Vorontsov <avorontsov@ru.mvista.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.
*/
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/libata.h>
#include <linux/ahci_platform.h>
#include "ahci.h"
static struct scsi_host_template ahci_platform_sht = {
AHCI_SHT("ahci_platform"),
};
static int __init ahci_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct ahci_platform_data *pdata = dev->platform_data;
struct ata_port_info pi = {
.flags = AHCI_FLAG_COMMON,
.pio_mask = ATA_PIO4,
.udma_mask = ATA_UDMA6,
.port_ops = &ahci_ops,
};
const struct ata_port_info *ppi[] = { &pi, NULL };
struct ahci_host_priv *hpriv;
struct ata_host *host;
struct resource *mem;
int irq;
int n_ports;
int i;
int rc;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem) {
dev_err(dev, "no mmio space\n");
return -EINVAL;
}
irq = platform_get_irq(pdev, 0);
if (irq <= 0) {
dev_err(dev, "no irq\n");
return -EINVAL;
}
if (pdata && pdata->ata_port_info)
pi = *pdata->ata_port_info;
hpriv = devm_kzalloc(dev, sizeof(*hpriv), GFP_KERNEL);
if (!hpriv) {
dev_err(dev, "can't alloc ahci_host_priv\n");
return -ENOMEM;
}
hpriv->flags |= (unsigned long)pi.private_data;
hpriv->mmio = devm_ioremap(dev, mem->start, resource_size(mem));
if (!hpriv->mmio) {
dev_err(dev, "can't map %pR\n", mem);
return -ENOMEM;
}
/*
* Some platforms might need to prepare for mmio region access,
* which could be done in the following init call. So, the mmio
* region shouldn't be accessed before init (if provided) has
* returned successfully.
*/
if (pdata && pdata->init) {
rc = pdata->init(dev, hpriv->mmio);
if (rc)
return rc;
}
ahci_save_initial_config(dev, hpriv,
pdata ? pdata->force_port_map : 0,
pdata ? pdata->mask_port_map : 0);
/* prepare host */
if (hpriv->cap & HOST_CAP_NCQ)
pi.flags |= ATA_FLAG_NCQ;
if (hpriv->cap & HOST_CAP_PMP)
pi.flags |= ATA_FLAG_PMP;
ahci_set_em_messages(hpriv, &pi);
/* CAP.NP sometimes indicate the index of the last enabled
* port, at other times, that of the last possible port, so
* determining the maximum port number requires looking at
* both CAP.NP and port_map.
*/
n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
host = ata_host_alloc_pinfo(dev, ppi, n_ports);
if (!host) {
rc = -ENOMEM;
goto err0;
}
host->private_data = hpriv;
if (!(hpriv->cap & HOST_CAP_SSS) || ahci_ignore_sss)
host->flags |= ATA_HOST_PARALLEL_SCAN;
else
printk(KERN_INFO "ahci: SSS flag set, parallel bus scan disabled\n");
if (pi.flags & ATA_FLAG_EM)
ahci_reset_em(host);
for (i = 0; i < host->n_ports; i++) {
struct ata_port *ap = host->ports[i];
ata_port_desc(ap, "mmio %pR", mem);
ata_port_desc(ap, "port 0x%x", 0x100 + ap->port_no * 0x80);
/* set enclosure management message type */
if (ap->flags & ATA_FLAG_EM)
ap->em_message_type = hpriv->em_msg_type;
/* disabled/not-implemented port */
if (!(hpriv->port_map & (1 << i)))
ap->ops = &ata_dummy_port_ops;
}
rc = ahci_reset_controller(host);
if (rc)
goto err0;
ahci_init_controller(host);
ahci_print_info(host, "platform");
rc = ata_host_activate(host, irq, ahci_interrupt, IRQF_SHARED,
&ahci_platform_sht);
if (rc)
goto err0;
return 0;
err0:
if (pdata && pdata->exit)
pdata->exit(dev);
return rc;
}
static int __devexit ahci_remove(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct ahci_platform_data *pdata = dev->platform_data;
struct ata_host *host = dev_get_drvdata(dev);
ata_host_detach(host);
if (pdata && pdata->exit)
pdata->exit(dev);
return 0;
}
static struct platform_driver ahci_driver = {
.remove = __devexit_p(ahci_remove),
.driver = {
.name = "ahci",
.owner = THIS_MODULE,
},
};
static int __init ahci_init(void)
{
return platform_driver_probe(&ahci_driver, ahci_probe);
}
module_init(ahci_init);
static void __exit ahci_exit(void)
{
platform_driver_unregister(&ahci_driver);
}
module_exit(ahci_exit);
MODULE_DESCRIPTION("AHCI SATA platform driver");
MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ahci");