Re: [RFC v2 16/18] ARM: OMAP2+: AM33XX: Basic suspend resume support

[Daniel Mack <zonque@gmail.com>]

Hi Vaibhav,

On Mon, Dec 31, 2012 at 2:07 PM, Vaibhav Bedia <vaibhav.bedia@ti.com> wrote:
> 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

May I ask about the plans for this series? Will you be re-spinning
them for a current
tree, and what's the planned merge window for it?


Many thanks,
Daniel




>
> 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@ti.com>
> Cc: Tony Lingren <tony@atomide.com>
> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Cc: Benoit Cousson <b-cousson@ti.com>
> Cc: Paul Walmsley <paul@pwsan.com>
> Cc: Kevin Hilman <khilman@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@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@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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