[RFC v2 16/18] ARM: OMAP2+: AM33XX: Basic suspend resume support
Vaibhav Bedia
vaibhav.bedia at ti.com
Mon Dec 31 08:07:09 EST 2012
AM335x supports various low power modes as documented
in section 8.1.4.3 of the AM335x TRM which is available
@ http://www.ti.com/litv/pdf/spruh73f
DeepSleep0 mode offers the lowest power mode with limited
wakeup sources without a system reboot and is mapped as
the suspend state in the kernel. In this state, MPU and
PER domains are turned off with the internal RAM held in
retention to facilitate resume process. As part of the boot
process, the assembly code is copied over to OCMCRAM using
the OMAP SRAM code.
AM335x has a Cortex-M3 (WKUP_M3) which assists the MPU
in DeepSleep0 entry and exit. WKUP_M3 takes care of the
clockdomain and powerdomain transitions based on the
intended low power state. MPU needs to load the appropriate
WKUP_M3 binary onto the WKUP_M3 memory space before it can
leverage any of the PM features like DeepSleep.
The IPC mechanism between MPU and WKUP_M3 uses a mailbox
sub-module and 8 IPC registers in the Control module. MPU
uses the assigned Mailbox for issuing an interrupt to
WKUP_M3 which then goes and checks the IPC registers for
the payload. WKUP_M3 has the ability to trigger on interrupt
to MPU by executing the "sev" instruction.
In the current implementation when the suspend process
is initiated MPU interrupts the WKUP_M3 to let it know about
the intent of entering DeepSleep0 and waits for an ACK. When
the ACK is received MPU continues with its suspend process
to suspend all the drivers and then jumps to assembly in
OCMC RAM. The assembly code puts the PLLs in bypass, puts the
external RAM in self-refresh mode and then finally execute the
WFI instruction. Execution of the WFI instruction triggers another
interrupt to the WKUP_M3 which then continues wiht the power down
sequence wherein the clockdomain and powerdomain transition takes
place. As part of the sleep sequence, WKUP_M3 unmasks the interrupt
lines for the wakeup sources. WFI execution on WKUP_M3 causes the
hardware to disable the main oscillator of the SoC.
When a wakeup event occurs, WKUP_M3 starts the power-up
sequence by switching on the power domains and finally
enabling the clock to MPU. Since the MPU gets powered down
as part of the sleep sequence in the resume path ROM code
starts executing. The ROM code detects a wakeup from sleep
and then jumps to the resume location in OCMC which was
populated in one of the IPC registers as part of the suspend
sequence.
The low level code in OCMC relocks the PLLs, enables access
to external RAM and then jumps to the cpu_resume code of
the kernel to finish the resume process.
Signed-off-by: Vaibhav Bedia <vaibhav.bedia at ti.com>
Cc: Tony Lingren <tony at atomide.com>
Cc: Santosh Shilimkar <santosh.shilimkar at ti.com>
Cc: Benoit Cousson <b-cousson at ti.com>
Cc: Paul Walmsley <paul at pwsan.com>
Cc: Kevin Hilman <khilman at deeprootsystems.com>
---
v1->v2:
Move assembly code addition, control module access
and hookup in OMAP PM framework in separate patches.
Address other comments from Kevin Hilman and Santosh
Shilimkar on v1. The discussion on v1 is present @
http://lists.infradead.org/pipermail/linux-arm-kernel/2012-November/129979.html
Note: The mailbox change will need slight rework once
the driver is finalized.
arch/arm/mach-omap2/pm33xx.c | 469 ++++++++++++++++++++++++++++++++++++++++++
arch/arm/mach-omap2/pm33xx.h | 56 +++++
2 files changed, 525 insertions(+), 0 deletions(-)
create mode 100644 arch/arm/mach-omap2/pm33xx.c
create mode 100644 arch/arm/mach-omap2/pm33xx.h
diff --git a/arch/arm/mach-omap2/pm33xx.c b/arch/arm/mach-omap2/pm33xx.c
new file mode 100644
index 0000000..aaa4daa
--- /dev/null
+++ b/arch/arm/mach-omap2/pm33xx.c
@@ -0,0 +1,469 @@
+/*
+ * AM33XX Power Management Routines
+ *
+ * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
+ * Vaibhav Bedia <vaibhav.bedia at ti.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/firmware.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/suspend.h>
+#include <linux/completion.h>
+#include <linux/module.h>
+#include <linux/mailbox.h>
+#include <linux/interrupt.h>
+
+#include <asm/suspend.h>
+#include <asm/proc-fns.h>
+#include <asm/sizes.h>
+#include <asm/fncpy.h>
+#include <asm/system_misc.h>
+
+#include "pm.h"
+#include "cm33xx.h"
+#include "pm33xx.h"
+#include "control.h"
+#include "clockdomain.h"
+#include "powerdomain.h"
+#include "omap_hwmod.h"
+#include "omap_device.h"
+#include "soc.h"
+#include "sram.h"
+
+void (*am33xx_do_wfi_sram)(void);
+
+static void __iomem *am33xx_emif_base;
+static struct powerdomain *cefuse_pwrdm, *gfx_pwrdm, *per_pwrdm;
+static struct clockdomain *gfx_l4ls_clkdm;
+static struct omap_hwmod *usb_oh, *cpsw_oh, *tptc0_oh, *tptc1_oh, *tptc2_oh;
+static struct wkup_m3_context *wkup_m3;
+
+static DECLARE_COMPLETION(wkup_m3_sync);
+
+#ifdef CONFIG_SUSPEND
+static int am33xx_do_sram_idle(long unsigned int unused)
+{
+ am33xx_do_wfi_sram();
+ return 0;
+}
+
+static int am33xx_pm_suspend(void)
+{
+ int status, ret = 0;
+
+ /*
+ * By default the following IPs do not have MSTANDBY asserted
+ * which is necessary for PER domain transition. If the drivers
+ * are not compiled into the kernel HWMOD code will not change the
+ * state of the IPs if the IP was not never enabled. To ensure
+ * that there no issues with or without the drivers being compiled
+ * in the kernel, we forcefully put these IPs to idle.
+ */
+ omap_hwmod_enable(usb_oh);
+ omap_hwmod_enable(tptc0_oh);
+ omap_hwmod_enable(tptc1_oh);
+ omap_hwmod_enable(tptc2_oh);
+ omap_hwmod_enable(cpsw_oh);
+
+ omap_hwmod_idle(usb_oh);
+ omap_hwmod_idle(tptc0_oh);
+ omap_hwmod_idle(tptc1_oh);
+ omap_hwmod_idle(tptc2_oh);
+ omap_hwmod_idle(cpsw_oh);
+
+ /* Try to put GFX to sleep */
+ pwrdm_set_next_fpwrst(gfx_pwrdm, PWRDM_FUNC_PWRST_OFF);
+
+ ret = cpu_suspend(0, am33xx_do_sram_idle);
+
+ status = pwrdm_read_fpwrst(gfx_pwrdm);
+ if (status != PWRDM_FUNC_PWRST_OFF)
+ pr_err("GFX domain did not transition\n");
+ else
+ pr_info("GFX domain entered low power state\n");
+
+ /*
+ * GFX_L4LS clock domain needs to be woken up to
+ * ensure thet L4LS clock domain does not get stuck in transition
+ * If that happens L3 module does not get disabled, thereby leading
+ * to PER power domain transition failing
+ *
+ * The clock framework should take care of ensuring
+ * that the clock domain is in the right state when
+ * GFX driver is active.
+ */
+ clkdm_wakeup(gfx_l4ls_clkdm);
+ clkdm_sleep(gfx_l4ls_clkdm);
+
+ if (ret) {
+ pr_err("Kernel suspend failure\n");
+ } else {
+ status = omap_ctrl_readl(AM33XX_CONTROL_IPC_MSG_REG1);
+ status &= IPC_RESP_MASK;
+ status >>= __ffs(IPC_RESP_MASK);
+
+ switch (status) {
+ case 0:
+ pr_info("Successfully put all powerdomains to target state\n");
+ /*
+ * XXX: Leads to loss of logic state in PER power domain
+ * Use SOC specific ops for this?
+ */
+ break;
+ case 1:
+ pr_err("Could not transition all powerdomains to target state\n");
+ ret = -1;
+ break;
+ default:
+ pr_err("Something went wrong :(\nStatus = %d\n",
+ status);
+ ret = -1;
+ }
+ }
+
+ return ret;
+}
+
+static int am33xx_pm_enter(suspend_state_t suspend_state)
+{
+ int ret = 0;
+
+ switch (suspend_state) {
+ case PM_SUSPEND_STANDBY:
+ case PM_SUSPEND_MEM:
+ ret = am33xx_pm_suspend();
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int am33xx_pm_begin(suspend_state_t state)
+{
+ int ret = 0;
+ struct mailbox_msg dummy_msg;
+
+ disable_hlt();
+
+ MAILBOX_FILL_HEADER_MSG(dummy_msg, 0xABCDABCD);
+
+ wkup_m3->ipc_data.sleep_mode = IPC_CMD_DS0;
+ wkup_m3->ipc_data.param1 = DS_IPC_DEFAULT;
+ wkup_m3->ipc_data.param2 = DS_IPC_DEFAULT;
+
+ am33xx_wkup_m3_ipc_cmd(&wkup_m3->ipc_data);
+
+ wkup_m3->state = M3_STATE_MSG_FOR_LP;
+
+ mailbox_enable_irq(wkup_m3->mbox, IRQ_RX);
+
+ ret = mailbox_msg_send(wkup_m3->mbox, &dummy_msg);
+ if (ret) {
+ pr_err("A8<->CM3 MSG for LP failed\n");
+ am33xx_m3_state_machine_reset();
+ ret = -1;
+ }
+
+ /* Give some time to M3 to respond. 500msec is a random value here */
+ if (!wait_for_completion_timeout(&wkup_m3_sync,
+ msecs_to_jiffies(500))) {
+ pr_err("A8<->CM3 sync failure\n");
+ am33xx_m3_state_machine_reset();
+ ret = -1;
+ } else {
+ pr_debug("Message sent for entering DeepSleep mode\n");
+ mailbox_disable_irq(wkup_m3->mbox, IRQ_RX);
+ }
+
+ return ret;
+}
+
+static void am33xx_pm_end(void)
+{
+ mailbox_enable_irq(wkup_m3->mbox, IRQ_RX);
+
+ am33xx_m3_state_machine_reset();
+
+ enable_hlt();
+
+ return;
+}
+
+static const struct platform_suspend_ops am33xx_pm_ops = {
+ .begin = am33xx_pm_begin,
+ .end = am33xx_pm_end,
+ .enter = am33xx_pm_enter,
+ .valid = suspend_valid_only_mem,
+};
+
+static void am33xx_m3_state_machine_reset(void)
+{
+ int ret = 0;
+ struct mailbox_msg dummy_msg;
+
+ MAILBOX_FILL_HEADER_MSG(dummy_msg, 0xABCDABCD);
+
+ wkup_m3->ipc_data.sleep_mode = IPC_CMD_RESET;
+ wkup_m3->ipc_data.param1 = DS_IPC_DEFAULT;
+ wkup_m3->ipc_data.param2 = DS_IPC_DEFAULT;
+
+ am33xx_wkup_m3_ipc_cmd(&wkup_m3->ipc_data);
+
+ wkup_m3->state = M3_STATE_MSG_FOR_RESET;
+
+ ret = mailbox_msg_send(wkup_m3->mbox, &dummy_msg);
+ if (!ret) {
+ pr_debug("Message sent for resetting M3 state machine\n");
+ /* Give some to M3 to respond. 500msec is a random value here */
+ if (!wait_for_completion_timeout(&wkup_m3_sync,
+ msecs_to_jiffies(500)))
+ pr_err("A8<->CM3 sync failure\n");
+ } else {
+ pr_err("Could not reset M3 state machine!!!\n");
+ wkup_m3->state = M3_STATE_UNKNOWN;
+ }
+}
+#endif /* CONFIG_SUSPEND */
+
+/*
+ * Dummy notifier for the mailbox
+ * XXX: Get rid of this requirement once the MBX driver has been finalized
+ */
+static int wkup_mbox_msg(struct notifier_block *self, unsigned long len,
+ void *msg)
+{
+ return 0;
+}
+
+static struct notifier_block wkup_mbox_notifier = {
+ .notifier_call = wkup_mbox_msg,
+};
+
+static irqreturn_t wkup_m3_txev_handler(int irq, void *unused)
+{
+ am33xx_txev_eoi();
+
+ switch (wkup_m3->state) {
+ case M3_STATE_RESET:
+ wkup_m3->state = M3_STATE_INITED;
+ break;
+ case M3_STATE_MSG_FOR_RESET:
+ wkup_m3->state = M3_STATE_INITED;
+ mailbox_rx_flush(wkup_m3->mbox);
+ complete(&wkup_m3_sync);
+ break;
+ case M3_STATE_MSG_FOR_LP:
+ mailbox_rx_flush(wkup_m3->mbox);
+ complete(&wkup_m3_sync);
+ break;
+ case M3_STATE_UNKNOWN:
+ pr_err("IRQ %d with WKUP_M3 in unknown state\n", irq);
+ mailbox_rx_flush(wkup_m3->mbox);
+ return IRQ_NONE;
+ }
+
+ am33xx_txev_enable();
+ return IRQ_HANDLED;
+}
+
+static void am33xx_pm_firmware_cb(const struct firmware *fw, void *context)
+{
+ struct wkup_m3_context *wkup_m3_context = context;
+ struct platform_device *pdev = to_platform_device(wkup_m3_context->dev);
+ int ret = 0;
+
+ /* no firmware found */
+ if (!fw) {
+ dev_err(wkup_m3_context->dev, "request_firmware failed\n");
+ goto err;
+ }
+
+ memcpy((void *)wkup_m3_context->code, fw->data, fw->size);
+ pr_info("Copied the M3 firmware to UMEM\n");
+
+ wkup_m3->state = M3_STATE_RESET;
+
+ ret = omap_device_deassert_hardreset(pdev, "wkup_m3");
+ if (ret) {
+ pr_err("Could not deassert the reset for WKUP_M3\n");
+ goto err;
+ } else {
+#ifdef CONFIG_SUSPEND
+ suspend_set_ops(&am33xx_pm_ops);
+ /*
+ * Physical resume address to be used by ROM code
+ */
+ wkup_m3->ipc_data.resume_addr = (AM33XX_OCMC_END -
+ am33xx_do_wfi_sz + am33xx_resume_offset + 0x4);
+#endif
+ return;
+ }
+
+err:
+ mailbox_put(wkup_m3_context->mbox, &wkup_mbox_notifier);
+}
+
+static int wkup_m3_init(void)
+{
+ int irq, ret = 0;
+ struct resource *mem;
+ struct platform_device *pdev = to_platform_device(wkup_m3->dev);
+
+ omap_device_enable_hwmods(to_omap_device(pdev));
+
+ /* Reserve the MBOX for sending messages to M3 */
+ wkup_m3->mbox = mailbox_get("wkup_m3", &wkup_mbox_notifier);
+ if (IS_ERR(wkup_m3->mbox)) {
+ pr_err("Could not reserve mailbox for A8->M3 IPC\n");
+ ret = -ENODEV;
+ goto exit;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (!irq) {
+ dev_err(wkup_m3->dev, "no irq resource\n");
+ ret = -ENXIO;
+ goto err;
+ }
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!mem) {
+ dev_err(wkup_m3->dev, "no memory resource\n");
+ ret = -ENXIO;
+ goto err;
+ }
+
+ wkup_m3->code = devm_request_and_ioremap(wkup_m3->dev, mem);
+ if (!wkup_m3->code) {
+ dev_err(wkup_m3->dev, "could not ioremap\n");
+ ret = -EADDRNOTAVAIL;
+ goto err;
+ }
+
+ ret = devm_request_irq(wkup_m3->dev, irq, wkup_m3_txev_handler,
+ IRQF_DISABLED, "wkup_m3_txev", NULL);
+ if (ret) {
+ dev_err(wkup_m3->dev, "request_irq failed\n");
+ goto err;
+ } else {
+ am33xx_txev_enable();
+ }
+
+ pr_info("Trying to load am335x-pm-firmware.bin");
+
+ /* We don't want to delay boot */
+ request_firmware_nowait(THIS_MODULE, 0, "am335x-pm-firmware.bin",
+ wkup_m3->dev, GFP_KERNEL, wkup_m3,
+ am33xx_pm_firmware_cb);
+ return 0;
+
+err:
+ mailbox_put(wkup_m3->mbox, &wkup_mbox_notifier);
+exit:
+ return ret;
+}
+
+/*
+ * Push the minimal suspend-resume code to SRAM
+ */
+void am33xx_push_sram_idle(void)
+{
+ am33xx_do_wfi_sram = (void *)omap_sram_push
+ (am33xx_do_wfi, am33xx_do_wfi_sz);
+}
+
+static int __init am33xx_map_emif(void)
+{
+ am33xx_emif_base = ioremap(AM33XX_EMIF_BASE, SZ_32K);
+
+ if (!am33xx_emif_base)
+ return -ENOMEM;
+
+ return 0;
+}
+
+void __iomem *am33xx_get_emif_base(void)
+{
+ return am33xx_emif_base;
+}
+
+int __init am33xx_pm_init(void)
+{
+ int ret;
+
+ if (!soc_is_am33xx())
+ return -ENODEV;
+
+ pr_info("Power Management for AM33XX family\n");
+
+ /*
+ * By default the following IPs do not have MSTANDBY asserted
+ * which is necessary for PER domain transition. If the drivers
+ * are not compiled into the kernel HWMOD code will not change the
+ * state of the IPs if the IP was not never enabled
+ */
+ usb_oh = omap_hwmod_lookup("usb_otg_hs");
+ tptc0_oh = omap_hwmod_lookup("tptc0");
+ tptc1_oh = omap_hwmod_lookup("tptc1");
+ tptc2_oh = omap_hwmod_lookup("tptc2");
+ cpsw_oh = omap_hwmod_lookup("cpgmac0");
+
+ gfx_pwrdm = pwrdm_lookup("gfx_pwrdm");
+ per_pwrdm = pwrdm_lookup("per_pwrdm");
+
+ gfx_l4ls_clkdm = clkdm_lookup("gfx_l4ls_gfx_clkdm");
+
+ if ((!usb_oh) || (!tptc0_oh) || (!tptc1_oh) || (!tptc2_oh) ||
+ (!cpsw_oh) || (!gfx_pwrdm) || (!per_pwrdm) ||
+ (!gfx_l4ls_clkdm)) {
+ ret = -ENODEV;
+ goto err;
+ }
+
+ wkup_m3 = kzalloc(sizeof(struct wkup_m3_context), GFP_KERNEL);
+ if (!wkup_m3) {
+ pr_err("Memory allocation failed\n");
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ ret = am33xx_map_emif();
+ if (ret) {
+ pr_err("Could not ioremap EMIF\n");
+ goto err;
+ }
+
+ (void) clkdm_for_each(omap_pm_clkdms_setup, NULL);
+
+ /* CEFUSE domain can be turned off post bootup */
+ cefuse_pwrdm = pwrdm_lookup("cefuse_pwrdm");
+ if (cefuse_pwrdm)
+ pwrdm_set_next_fpwrst(cefuse_pwrdm, PWRDM_FUNC_PWRST_OFF);
+ else
+ pr_err("Failed to get cefuse_pwrdm\n");
+
+ wkup_m3->dev = omap_device_get_by_hwmod_name("wkup_m3");
+
+ ret = wkup_m3_init();
+ if (ret)
+ pr_err("Could not initialise firmware loading\n");
+
+err:
+ return ret;
+}
diff --git a/arch/arm/mach-omap2/pm33xx.h b/arch/arm/mach-omap2/pm33xx.h
new file mode 100644
index 0000000..13a2c85
--- /dev/null
+++ b/arch/arm/mach-omap2/pm33xx.h
@@ -0,0 +1,56 @@
+/*
+ * AM33XX Power Management Routines
+ *
+ * Copyright (C) 2012 Texas Instruments Inc.
+ * Vaibhav Bedia <vaibhav.bedia at ti.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 version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+#ifndef __ARCH_ARM_MACH_OMAP2_PM33XX_H
+#define __ARCH_ARM_MACH_OMAP2_PM33XX_H
+
+#include "control.h"
+
+#ifndef __ASSEMBLER__
+struct wkup_m3_context {
+ struct am33xx_ipc_data ipc_data;
+ struct device *dev;
+ struct firmware *firmware;
+ struct mailbox *mbox;
+ void __iomem *code;
+ u8 state;
+};
+
+#ifdef CONFIG_SUSPEND
+static void am33xx_m3_state_machine_reset(void);
+#else
+static inline void am33xx_m3_state_machine_reset(void) {}
+#endif /* CONFIG_SUSPEND */
+
+extern void __iomem *am33xx_get_emif_base(void);
+#endif
+
+#define IPC_CMD_DS0 0x3
+#define IPC_CMD_RESET 0xe
+#define DS_IPC_DEFAULT 0xffffffff
+
+#define IPC_RESP_SHIFT 16
+#define IPC_RESP_MASK (0xffff << 16)
+
+#define M3_STATE_UNKNOWN 0
+#define M3_STATE_RESET 1
+#define M3_STATE_INITED 2
+#define M3_STATE_MSG_FOR_LP 3
+#define M3_STATE_MSG_FOR_RESET 4
+
+#define AM33XX_OCMC_END 0x40310000
+#define AM33XX_EMIF_BASE 0x4C000000
+
+#endif
--
1.7.0.4
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