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PCI: j721e: Add suspend and resume support

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Add suspend and resume support. Only the Root Complex mode is supported.

During the suspend stage PERST# is asserted, then deasserted during the
resume stage.

Link: https://lore.kernel.org/linux-pci/20240102-j7200-pcie-s2r-v7-7-a2f9156da6c3@bootlin.com
Signed-off-by: Théo Lebrun <theo.lebrun@bootlin.com>
Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
[kwilczynski: commit log, update references to the PCI SIG specification]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>
This commit is contained in:
Théo Lebrun 2024-06-19 12:15:15 +02:00 committed by Krzysztof Wilczyński
parent f96b697137
commit c538d40f36
No known key found for this signature in database
GPG Key ID: 7C64768D3DE334E7
1 changed files with 92 additions and 6 deletions
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98
drivers/pci/controller/cadence/pci-j721e.c
View File

@ -7,6 +7,8 @@
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/container_of.h>
#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
@ -22,6 +24,8 @@
#include "../../pci.h"
#include "pcie-cadence.h"
#define cdns_pcie_to_rc(p) container_of(p, struct cdns_pcie_rc, pcie)
#define ENABLE_REG_SYS_2 0x108
#define STATUS_REG_SYS_2 0x508
#define STATUS_CLR_REG_SYS_2 0x708
@ -568,12 +572,12 @@ static int j721e_pcie_probe(struct platform_device *pdev)
pcie->refclk = clk;
/*
* "Power Sequencing and Reset Signal Timings" table in
* PCI EXPRESS CARD ELECTROMECHANICAL SPECIFICATION, REV. 3.0
* indicates PERST# should be deasserted after minimum of 100us
* once REFCLK is stable. The REFCLK to the connector in RC
* mode is selected while enabling the PHY. So deassert PERST#
* after 100 us.
* The "Power Sequencing and Reset Signal Timings" table of the
* PCI Express Card Electromechanical Specification, Revision
* 5.1, Section 2.9.2, Symbol "T_PERST-CLK", indicates PERST#
* should be deasserted after minimum of 100us once REFCLK is
* stable. The REFCLK to the connector in RC mode is selected
* while enabling the PHY. So deassert PERST# after 100 us.
*/
if (gpiod) {
fsleep(PCIE_T_PERST_CLK_US);
@ -625,6 +629,87 @@ static void j721e_pcie_remove(struct platform_device *pdev)
pm_runtime_disable(dev);
}
static int j721e_pcie_suspend_noirq(struct device *dev)
{
struct j721e_pcie *pcie = dev_get_drvdata(dev);
if (pcie->mode == PCI_MODE_RC) {
gpiod_set_value_cansleep(pcie->reset_gpio, 0);
clk_disable_unprepare(pcie->refclk);
}
cdns_pcie_disable_phy(pcie->cdns_pcie);
return 0;
}
static int j721e_pcie_resume_noirq(struct device *dev)
{
struct j721e_pcie *pcie = dev_get_drvdata(dev);
struct cdns_pcie *cdns_pcie = pcie->cdns_pcie;
int ret;
ret = j721e_pcie_ctrl_init(pcie);
if (ret < 0)
return ret;
j721e_pcie_config_link_irq(pcie);
/*
* This is not called explicitly in the probe, it is called by
* cdns_pcie_init_phy().
*/
ret = cdns_pcie_enable_phy(pcie->cdns_pcie);
if (ret < 0)
return ret;
if (pcie->mode == PCI_MODE_RC) {
struct cdns_pcie_rc *rc = cdns_pcie_to_rc(cdns_pcie);
ret = clk_prepare_enable(pcie->refclk);
if (ret < 0)
return ret;
/*
* The "Power Sequencing and Reset Signal Timings" table of the
* PCI Express Card Electromechanical Specification, Revision
* 5.1, Section 2.9.2, Symbol "T_PERST-CLK", indicates PERST#
* should be deasserted after minimum of 100us once REFCLK is
* stable. The REFCLK to the connector in RC mode is selected
* while enabling the PHY. So deassert PERST# after 100 us.
*/
if (pcie->reset_gpio) {
fsleep(PCIE_T_PERST_CLK_US);
gpiod_set_value_cansleep(pcie->reset_gpio, 1);
}
ret = cdns_pcie_host_link_setup(rc);
if (ret < 0) {
clk_disable_unprepare(pcie->refclk);
return ret;
}
/*
* Reset internal status of BARs to force reinitialization in
* cdns_pcie_host_init().
*/
for (enum cdns_pcie_rp_bar bar = RP_BAR0; bar <= RP_NO_BAR; bar++)
rc->avail_ib_bar[bar] = true;
ret = cdns_pcie_host_init(rc);
if (ret) {
clk_disable_unprepare(pcie->refclk);
return ret;
}
}
return 0;
}
static DEFINE_NOIRQ_DEV_PM_OPS(j721e_pcie_pm_ops,
j721e_pcie_suspend_noirq,
j721e_pcie_resume_noirq);
static struct platform_driver j721e_pcie_driver = {
.probe = j721e_pcie_probe,
.remove_new = j721e_pcie_remove,
@ -632,6 +717,7 @@ static struct platform_driver j721e_pcie_driver = {
.name = "j721e-pcie",
.of_match_table = of_j721e_pcie_match,
.suppress_bind_attrs = true,
.pm = pm_sleep_ptr(&j721e_pcie_pm_ops),
},
};
builtin_platform_driver(j721e_pcie_driver);