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[ Upstream commitf67f12ff57] Currently the ACHI-platform library supports only the assert and deassert reset signals and ignores the platforms with self-deasserting reset lines. That prone to having the platforms with self-deasserting reset method misbehaviour when it comes to resuming from sleep state after the clocks have been fully disabled. For such cases the controller needs to be fully reset all over after the reference clocks are enabled and stable, otherwise the controller state machine might be in an undetermined state. The best solution would be to auto-detect which reset method is supported by the particular platform and use it implicitly in the framework of the ahci_platform_enable_resources()/ahci_platform_disable_resources() methods. Alas it can't be implemented due to the AHCI-platform library already supporting the shared reset control lines. As [1] says in such case we have to use only one of the next methods: + reset_control_assert()/reset_control_deassert(); + reset_control_reset()/reset_control_rearm(). If the driver had an exclusive control over the reset lines we could have been able to manipulate the lines with no much limitation and just used the combination of the methods above to cover all the possible reset-control cases. Since the shared reset control has already been advertised and couldn't be changed with no risk to breaking the platforms relying on it, we have no choice but to make the platform drivers to determine which reset methods the platform reset system supports. In order to implement both types of reset control support we suggest to introduce the new AHCI-platform flag: AHCI_PLATFORM_RST_TRIGGER, which when passed to the ahci_platform_get_resources() method together with the AHCI_PLATFORM_GET_RESETS flag will indicate that the reset lines are self-deasserting thus the reset_control_reset()/reset_control_rearm() will be used to control the reset state. Otherwise the reset_control_deassert()/reset_control_assert() methods will be utilized. [1] Documentation/driver-api/reset.rst Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Stable-dep-of:26c8404e16("ata: ahci_ceva: fix error handling for Xilinx GT PHY support") Signed-off-by: Sasha Levin <sashal@kernel.org>
50 lines
1.7 KiB
C
50 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* AHCI SATA platform driver
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*
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* Copyright 2004-2005 Red Hat, Inc.
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* Jeff Garzik <jgarzik@pobox.com>
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* Copyright 2010 MontaVista Software, LLC.
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* Anton Vorontsov <avorontsov@ru.mvista.com>
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*/
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#ifndef _AHCI_PLATFORM_H
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#define _AHCI_PLATFORM_H
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#include <linux/compiler.h>
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struct device;
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struct ata_port_info;
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struct ahci_host_priv;
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struct platform_device;
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struct scsi_host_template;
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int ahci_platform_enable_phys(struct ahci_host_priv *hpriv);
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void ahci_platform_disable_phys(struct ahci_host_priv *hpriv);
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int ahci_platform_enable_clks(struct ahci_host_priv *hpriv);
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void ahci_platform_disable_clks(struct ahci_host_priv *hpriv);
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int ahci_platform_deassert_rsts(struct ahci_host_priv *hpriv);
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int ahci_platform_assert_rsts(struct ahci_host_priv *hpriv);
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int ahci_platform_enable_regulators(struct ahci_host_priv *hpriv);
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void ahci_platform_disable_regulators(struct ahci_host_priv *hpriv);
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int ahci_platform_enable_resources(struct ahci_host_priv *hpriv);
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void ahci_platform_disable_resources(struct ahci_host_priv *hpriv);
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struct ahci_host_priv *ahci_platform_get_resources(
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struct platform_device *pdev, unsigned int flags);
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int ahci_platform_init_host(struct platform_device *pdev,
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struct ahci_host_priv *hpriv,
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const struct ata_port_info *pi_template,
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struct scsi_host_template *sht);
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void ahci_platform_shutdown(struct platform_device *pdev);
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int ahci_platform_suspend_host(struct device *dev);
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int ahci_platform_resume_host(struct device *dev);
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int ahci_platform_suspend(struct device *dev);
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int ahci_platform_resume(struct device *dev);
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#define AHCI_PLATFORM_GET_RESETS BIT(0)
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#define AHCI_PLATFORM_RST_TRIGGER BIT(1)
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#endif /* _AHCI_PLATFORM_H */
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