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Date: Fri, 17 Jan 2014 15:46:40 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Linux PM list <linux-pm@...r.kernel.org>
Cc: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: [RFC/RFT][PATCH 4/5] ACPI / LPSS: Support for device latency tolerance PM QoS
From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Add a new routine, acpi_lpss_set_ltr(), for setting latency tolerance
values for LPSS devices having LTR (Latency Tolerance Reporting)
registers. Modify acpi_lpss_platform_notify() to set the LPSS
devices' power.set_latency_tolerance callback pointers to
acpi_lpss_set_ltr() during device addition.
That will cause the device latency tolerance PM QoS to work for
the devices in question as documented.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
drivers/acpi/acpi_lpss.c | 66 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 62 insertions(+), 4 deletions(-)
Index: linux-pm/drivers/acpi/acpi_lpss.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpi_lpss.c
+++ linux-pm/drivers/acpi/acpi_lpss.c
@@ -33,6 +33,12 @@ ACPI_MODULE_NAME("acpi_lpss");
#define LPSS_GENERAL_UART_RTS_OVRD BIT(3)
#define LPSS_SW_LTR 0x10
#define LPSS_AUTO_LTR 0x14
+#define LPSS_LTR_SNOOP_REQ BIT(15)
+#define LPSS_LTR_SNOOP_MASK 0x0000FFFF
+#define LPSS_LTR_SNOOP_LAT_1US 0x800
+#define LPSS_LTR_SNOOP_LAT_32US 0xC00
+#define LPSS_LTR_SNOOP_LAT_SHIFT 5
+#define LPSS_LTR_MAX_VAL 0x3FF
#define LPSS_TX_INT 0x20
#define LPSS_TX_INT_MASK BIT(1)
@@ -316,6 +322,17 @@ static int acpi_lpss_create_device(struc
return ret;
}
+static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
+{
+ return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
+static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
+ unsigned int reg)
+{
+ writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
{
struct acpi_device *adev;
@@ -337,7 +354,7 @@ static int lpss_reg_read(struct device *
ret = -ENODEV;
goto out;
}
- *val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+ *val = __lpss_reg_read(pdata, reg);
out:
spin_unlock_irqrestore(&dev->power.lock, flags);
@@ -390,6 +407,46 @@ static struct attribute_group lpss_attr_
.name = "lpss_ltr",
};
+static void acpi_lpss_set_ltr(struct device *dev, s32 val)
+{
+ struct acpi_device *adev = ACPI_COMPANION(dev);
+ struct lpss_private_data *pdata;
+ u32 ltr_mode, ltr_val;
+
+ if (WARN_ON(!adev))
+ return;
+
+ pdata = acpi_driver_data(adev);
+ if (WARN_ON(!pdata || !pdata->mmio_base))
+ return;
+
+ ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
+ if (val < 0) {
+ if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
+ ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
+ __lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+ }
+ return;
+ }
+ ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
+ if (val > LPSS_LTR_MAX_VAL) {
+ ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
+ val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
+ if (val > LPSS_LTR_MAX_VAL)
+ val = LPSS_LTR_MAX_VAL;
+ } else {
+ ltr_val |= LPSS_LTR_SNOOP_LAT_1US;
+ if (val > 0)
+ ltr_val |= LPSS_LTR_SNOOP_REQ;
+ }
+ ltr_val |= val;
+ __lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
+ if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
+ ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
+ __lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+ }
+}
+
static int acpi_lpss_platform_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
@@ -415,11 +472,12 @@ static int acpi_lpss_platform_notify(str
return 0;
}
- if (action == BUS_NOTIFY_ADD_DEVICE)
+ if (action == BUS_NOTIFY_ADD_DEVICE) {
ret = sysfs_create_group(&pdev->dev.kobj, &lpss_attr_group);
- else if (action == BUS_NOTIFY_DEL_DEVICE)
+ pdev->dev.power.set_latency_tolerance = acpi_lpss_set_ltr;
+ } else if (action == BUS_NOTIFY_DEL_DEVICE) {
sysfs_remove_group(&pdev->dev.kobj, &lpss_attr_group);
-
+ }
return ret;
}
--
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