Re: [PATCH V8 3/4] PCI: tegra: Broadcast PME_Turn_Off message before link goes to L2

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On 26-Feb-18 9:24 PM, Lorenzo Pieralisi wrote:
> On Tue, Feb 13, 2018 at 08:54:09PM +0530, Manikanta Maddireddy wrote:
>> Per PCIe r3.0, sec 5.3.3.2.1, PCIe root port shoould broadcast PME_Turn_Off
> 
> s/shoould/should
> 
>> message before PCIe link goes to L2. PME_Turn_Off broadcast mechanism is
>> implemented in AFI module. Each Tegra PCIe root port has its own
>> PME_Turn_Off and PME_TO_Ack bitmap in AFI_PME register, program this
>> register to broadcast PME_Turn_Off message.
>>
>> Signed-off-by: Manikanta Maddireddy <mmaddireddy@xxxxxxxxxx>
>> Acked-by: Thierry Reding <treding@xxxxxxxxxx>
>> Tested-by: Thierry Reding <treding@xxxxxxxxxx>
>> ---
>> V2:
>> * no change in this patch
>> V3:
>> * add PME bitmap in soc data instead of using compatible string
>> * replace while loop with readl_poll_timeout() for polling
>> * commit log correction
>> V4:
>> * no change in this patch
>> V5:
>> * Rebased on linux-next
>> V6:
>> * no change in this patch
>> V7:
>> * Per port soc data is added for pme bits
>> * list_for_each_entry_safe is changed to list_for_each_entry for pme turnoff
>> V8:
>> * Rebased on top of latest patch-2
>>
>>  drivers/pci/host/pci-tegra.c | 66 ++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 66 insertions(+)
>>
>> diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
>> index 17ccb5e3ba04..60b1d5e1cfa4 100644
>> --- a/drivers/pci/host/pci-tegra.c
>> +++ b/drivers/pci/host/pci-tegra.c
>> @@ -31,6 +31,7 @@
>>  #include <linux/delay.h>
>>  #include <linux/export.h>
>>  #include <linux/interrupt.h>
>> +#include <linux/iopoll.h>
>>  #include <linux/irq.h>
>>  #include <linux/irqdomain.h>
>>  #include <linux/kernel.h>
>> @@ -153,6 +154,8 @@
>>  #define  AFI_INTR_EN_FPCI_TIMEOUT	(1 << 7)
>>  #define  AFI_INTR_EN_PRSNT_SENSE	(1 << 8)
>>  
>> +#define AFI_PCIE_PME		0xf0
>> +
>>  #define AFI_PCIE_CONFIG					0x0f8
>>  #define  AFI_PCIE_CONFIG_PCIE_DISABLE(x)		(1 << ((x) + 1))
>>  #define  AFI_PCIE_CONFIG_PCIE_DISABLE_ALL		0xe
>> @@ -233,6 +236,8 @@
>>  #define PADS_REFCLK_CFG_PREDI_SHIFT		8  /* 11:8 */
>>  #define PADS_REFCLK_CFG_DRVI_SHIFT		12 /* 15:12 */
>>  
>> +#define PME_ACK_TIMEOUT 10000
>> +
>>  struct tegra_msi {
>>  	struct msi_controller chip;
>>  	DECLARE_BITMAP(used, INT_PCI_MSI_NR);
>> @@ -244,8 +249,16 @@ struct tegra_msi {
>>  };
>>  
>>  /* used to differentiate between Tegra SoC generations */
>> +struct tegra_pcie_port_soc {
>> +	struct {
>> +		u8 turnoff_bit;
>> +		u8 ack_bit;
>> +	} pme;
>> +};
>> +
>>  struct tegra_pcie_soc {
>>  	unsigned int num_ports;
>> +	const struct tegra_pcie_port_soc *ports;
>>  	unsigned int msi_base_shift;
>>  	u32 pads_pll_ctl;
>>  	u32 tx_ref_sel;
>> @@ -1358,6 +1371,32 @@ static int tegra_pcie_put_resources(struct tegra_pcie *pcie)
>>  	return 0;
>>  }
>>  
>> +static void tegra_pcie_pme_turnoff(struct tegra_pcie_port *port)
>> +{
>> +	struct tegra_pcie *pcie = port->pcie;
>> +	const struct tegra_pcie_soc *soc = pcie->soc;
>> +	int err;
>> +	u32 val;
>> +	u8 ack_bit;
>> +
>> +	val = afi_readl(pcie, AFI_PCIE_PME);
>> +	val |= (0x1 << soc->ports[port->index].pme.turnoff_bit);
>> +	afi_writel(pcie, val, AFI_PCIE_PME);
>> +
>> +	ack_bit = soc->ports[port->index].pme.ack_bit;
>> +	err = readl_poll_timeout(pcie->afi + AFI_PCIE_PME, val,
>> +				 val & (0x1 << ack_bit), 1, PME_ACK_TIMEOUT);
>> +	if (err)
>> +		dev_err(pcie->dev, "PME Ack is not received on port: %d\n",
>> +			port->index);
>> +
>> +	usleep_range(10000, 11000);
>> +
>> +	val = afi_readl(pcie, AFI_PCIE_PME);
>> +	val &= ~(0x1 << soc->ports[port->index].pme.turnoff_bit);
>> +	afi_writel(pcie, val, AFI_PCIE_PME);
>> +}
>> +
>>  static int tegra_msi_alloc(struct tegra_msi *chip)
>>  {
>>  	int msi;
>> @@ -2103,8 +2142,14 @@ static void tegra_pcie_disable_ports(struct tegra_pcie *pcie)
>>  	}
>>  }
>>  
>> +static const struct tegra_pcie_port_soc tegra20_pcie_ports[] = {
>> +	{ .pme.turnoff_bit = 0, .pme.ack_bit =  5 },
>> +	{ .pme.turnoff_bit = 8, .pme.ack_bit = 10 },
>> +};
>> +
>>  static const struct tegra_pcie_soc tegra20_pcie = {
>>  	.num_ports = 2,
>> +	.ports = tegra20_pcie_ports,
>>  	.msi_base_shift = 0,
>>  	.pads_pll_ctl = PADS_PLL_CTL_TEGRA20,
>>  	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_DIV10,
>> @@ -2118,8 +2163,15 @@ static const struct tegra_pcie_soc tegra20_pcie = {
>>  	.program_uphy = true,
>>  };
>>  
>> +static const struct tegra_pcie_port_soc tegra30_pcie_ports[] = {
>> +	{ .pme.turnoff_bit =  0, .pme.ack_bit =  5 },
>> +	{ .pme.turnoff_bit =  8, .pme.ack_bit = 10 },
>> +	{ .pme.turnoff_bit = 16, .pme.ack_bit = 18 },
>> +};
>> +
>>  static const struct tegra_pcie_soc tegra30_pcie = {
>>  	.num_ports = 3,
>> +	.ports = tegra30_pcie_ports,
>>  	.msi_base_shift = 8,
>>  	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
>>  	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
>> @@ -2136,6 +2188,7 @@ static const struct tegra_pcie_soc tegra30_pcie = {
>>  
>>  static const struct tegra_pcie_soc tegra124_pcie = {
>>  	.num_ports = 2,
>> +	.ports = tegra20_pcie_ports,
>>  	.msi_base_shift = 8,
>>  	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
>>  	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
>> @@ -2151,6 +2204,7 @@ static const struct tegra_pcie_soc tegra124_pcie = {
>>  
>>  static const struct tegra_pcie_soc tegra210_pcie = {
>>  	.num_ports = 2,
>> +	.ports = tegra20_pcie_ports,
>>  	.msi_base_shift = 8,
>>  	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
>>  	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
>> @@ -2164,8 +2218,15 @@ static const struct tegra_pcie_soc tegra210_pcie = {
>>  	.program_uphy = true,
>>  };
>>  
>> +static const struct tegra_pcie_port_soc tegra186_pcie_ports[] = {
>> +	{ .pme.turnoff_bit =  0, .pme.ack_bit =  5 },
>> +	{ .pme.turnoff_bit =  8, .pme.ack_bit = 10 },
>> +	{ .pme.turnoff_bit = 12, .pme.ack_bit = 14 },
>> +};
>> +
>>  static const struct tegra_pcie_soc tegra186_pcie = {
>>  	.num_ports = 3,
>> +	.ports = tegra186_pcie_ports,
>>  	.msi_base_shift = 8,
>>  	.pads_pll_ctl = PADS_PLL_CTL_TEGRA30,
>>  	.tx_ref_sel = PADS_PLL_CTL_TXCLKREF_BUF_EN,
>> @@ -2399,12 +2460,17 @@ static int tegra_pcie_remove(struct platform_device *pdev)
>>  {
>>  	struct tegra_pcie *pcie = platform_get_drvdata(pdev);
>>  	struct pci_host_bridge *host = pci_host_bridge_from_priv(pcie);
>> +	struct tegra_pcie_port *port;
>>  
>>  	if (IS_ENABLED(CONFIG_DEBUG_FS))
>>  		tegra_pcie_debugfs_exit(pcie);
>>  
>>  	pci_stop_root_bus(host->bus);
>>  	pci_remove_root_bus(host->bus);
>> +
>> +	list_for_each_entry(port, &pcie->ports, list)
>> +		tegra_pcie_pme_turnoff(port);
>> +
> 
> IIUC how it works this patch and the previous one should be swapped,
> otherwise the driver removal may not work correctly.
> 
> It is just for my own understanding (and bisection reasons).
> 
> Thanks,
> Lorenzo
> 
Hi Lorenzo,

Previous patch implements the driver removal code, without that
we cannot add PME_TurnOff logic. IMO we need squash previous
patch & this one to have working removal code with single patch.
This takes care of bisection issue as well.

Thanks,
Manikanta

>>  	tegra_pcie_disable_ports(pcie);
>>  
>>  	if (IS_ENABLED(CONFIG_PCI_MSI))
>> -- 
>> 2.1.4
>>
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