Re: [PATCH] link up validation moved to pcie-designware

From: Joao Pinto
Date: Mon Feb 08 2016 - 10:12:38 EST

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Hi Gab,
This patch is part of the on going work of integrating a designware platform
driver that is SoC agnostic. This code replication issue was raised during
discussions.

Thanks
Joao

On 2/8/2016 1:03 PM, Gabriele Paoloni wrote:
> Hi Joao
>
>> -----Original Message-----
>> From: linux-pci-owner@xxxxxxxxxxxxxxx [mailto:linux-pci-
>> owner@xxxxxxxxxxxxxxx] On Behalf Of Joao Pinto
>> Sent: 08 February 2016 12:44
>> To: helgaas@xxxxxxxxxx
>> Cc: arnd@xxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; linux-
>> kernel@xxxxxxxxxxxxxxx; CARLOS.PALMINHA@xxxxxxxxxxxx; Joao Pinto
>> Subject: [PATCH] link up validation moved to pcie-designware
>>
>> This patch goal is to centralize in pcie-designware the link up
>> validation. A new function was added to pci-designware that is
>> responsible for doing such a task. This was implemented in a form that
>> permits flexibility for all SoCs.
>
> Looking at the patch I don't think this is really needed,
> it seems to me like it makes more confusion in reading the
> drivers code.
>
> It is clear that each HW IP has got his own transient time
> in setting the link up, this is clear looking at the code
> of the single drivers now.
>
> With the modification you are proposing we are seeing
> drivers calls with magic numbers and the need for the
> reader to go and look into the designware framework to
> understand a function that is not even designware
> specific (in fact all these drivers need to wait different
> times according to their HW IP and some other drivers do
> not need to wait at all...)
>
> BTW I am quite new to PCIe so let's see what the other guys
> think...
>
> Cheers
>
> Gab
>
>>
>> Signed-off-by: Joao Pinto <jpinto@xxxxxxxxxxxx>
>> ---
>> drivers/pci/host/pci-dra7xx.c | 11 +++--------
>> drivers/pci/host/pci-exynos.c | 11 ++---------
>> drivers/pci/host/pci-imx6.c | 11 +++--------
>> drivers/pci/host/pcie-designware.c | 20 ++++++++++++++++++++
>> drivers/pci/host/pcie-designware.h | 2 ++
>> drivers/pci/host/pcie-spear13xx.c | 12 ++----------
>> 6 files changed, 32 insertions(+), 35 deletions(-)
>>
>> diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-
>> dra7xx.c
>> index 8c36880..e425944 100644
>> --- a/drivers/pci/host/pci-dra7xx.c
>> +++ b/drivers/pci/host/pci-dra7xx.c
>> @@ -10,7 +10,6 @@
>> * published by the Free Software Foundation.
>> */
>>
>> -#include <linux/delay.h>
>> #include <linux/err.h>
>> #include <linux/interrupt.h>
>> #include <linux/irq.h>
>> @@ -108,7 +107,6 @@ static int dra7xx_pcie_establish_link(struct
>> pcie_port *pp)
>> {
>> struct dra7xx_pcie *dra7xx = to_dra7xx_pcie(pp);
>> u32 reg;
>> - unsigned int retries;
>>
>> if (dw_pcie_link_up(pp)) {
>> dev_err(pp->dev, "link is already up\n");
>> @@ -119,13 +117,10 @@ static int dra7xx_pcie_establish_link(struct
>> pcie_port *pp)
>> reg |= LTSSM_EN;
>> dra7xx_pcie_writel(dra7xx, PCIECTRL_DRA7XX_CONF_DEVICE_CMD, reg);
>>
>> - for (retries = 0; retries < 1000; retries++) {
>> - if (dw_pcie_link_up(pp))
>> - return 0;
>> - usleep_range(10, 20);
>> - }
>> + /* check if the link is up or not */
>> + if (!dw_pcie_check_link_is_up(pp, 1000, 10, 20))
>> + return 0;
>>
>> - dev_err(pp->dev, "link is not up\n");
>> return -EINVAL;
>> }
>>
>> diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-
>> exynos.c
>> index 01095e1..770c45a 100644
>> --- a/drivers/pci/host/pci-exynos.c
>> +++ b/drivers/pci/host/pci-exynos.c
>> @@ -318,7 +318,6 @@ static int exynos_pcie_establish_link(struct
>> pcie_port *pp)
>> {
>> struct exynos_pcie *exynos_pcie = to_exynos_pcie(pp);
>> u32 val;
>> - unsigned int retries;
>>
>> if (dw_pcie_link_up(pp)) {
>> dev_err(pp->dev, "Link already up\n");
>> @@ -357,13 +356,8 @@ static int exynos_pcie_establish_link(struct
>> pcie_port *pp)
>> PCIE_APP_LTSSM_ENABLE);
>>
>> /* check if the link is up or not */
>> - for (retries = 0; retries < 10; retries++) {
>> - if (dw_pcie_link_up(pp)) {
>> - dev_info(pp->dev, "Link up\n");
>> - return 0;
>> - }
>> - mdelay(100);
>> - }
>> + if (!dw_pcie_check_link_is_up(pp, 10, 100000, 110000))
>> + return 0;
>>
>> while (exynos_phy_readl(exynos_pcie, PCIE_PHY_PLL_LOCKED) == 0) {
>> val = exynos_blk_readl(exynos_pcie, PCIE_PHY_PLL_LOCKED);
>> @@ -372,7 +366,6 @@ static int exynos_pcie_establish_link(struct
>> pcie_port *pp)
>> /* power off phy */
>> exynos_pcie_power_off_phy(pp);
>>
>> - dev_err(pp->dev, "PCIe Link Fail\n");
>> return -EINVAL;
>> }
>>
>> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
>> index 22e8224..9e323be 100644
>> --- a/drivers/pci/host/pci-imx6.c
>> +++ b/drivers/pci/host/pci-imx6.c
>> @@ -330,15 +330,10 @@ static void imx6_pcie_init_phy(struct pcie_port
>> *pp)
>>
>> static int imx6_pcie_wait_for_link(struct pcie_port *pp)
>> {
>> - unsigned int retries;
>> -
>> - for (retries = 0; retries < 200; retries++) {
>> - if (dw_pcie_link_up(pp))
>> - return 0;
>> - usleep_range(100, 1000);
>> - }
>> + /* check if the link is up or not */
>> + if (!dw_pcie_check_link_is_up(pp, 200, 100, 1000))
>> + return 0;
>>
>> - dev_err(pp->dev, "phy link never came up\n");
>> dev_dbg(pp->dev, "DEBUG_R0: 0x%08x, DEBUG_R1: 0x%08x\n",
>> readl(pp->dbi_base + PCIE_PHY_DEBUG_R0),
>> readl(pp->dbi_base + PCIE_PHY_DEBUG_R1));
>> diff --git a/drivers/pci/host/pcie-designware.c
>> b/drivers/pci/host/pcie-designware.c
>> index 540f077..6725231 100644
>> --- a/drivers/pci/host/pcie-designware.c
>> +++ b/drivers/pci/host/pcie-designware.c
>> @@ -22,6 +22,7 @@
>> #include <linux/pci_regs.h>
>> #include <linux/platform_device.h>
>> #include <linux/types.h>
>> +#include <linux/delay.h>
>>
>> #include "pcie-designware.h"
>>
>> @@ -380,6 +381,25 @@ static struct msi_controller dw_pcie_msi_chip = {
>> .teardown_irq = dw_msi_teardown_irq,
>> };
>>
>> +int dw_pcie_check_link_is_up(struct pcie_port *pp, int max_ret, int
>> sleep_min,
>> + int sleep_max)
>> +{
>> + int retries;
>> +
>> + /* check if the link is up or not */
>> + for (retries = 0; retries < max_ret; retries++) {
>> + if (dw_pcie_link_up(pp)) {
>> + dev_info(pp->dev, "link up\n");
>> + return 0;
>> + }
>> + usleep_range(sleep_min, sleep_max);
>> + }
>> +
>> + dev_err(pp->dev, "phy link never came up\n");
>> +
>> + return 1;
>> +}
>> +
>> int dw_pcie_link_up(struct pcie_port *pp)
>> {
>> if (pp->ops->link_up)
>> diff --git a/drivers/pci/host/pcie-designware.h
>> b/drivers/pci/host/pcie-designware.h
>> index 2356d29..b077fe0 100644
>> --- a/drivers/pci/host/pcie-designware.h
>> +++ b/drivers/pci/host/pcie-designware.h
>> @@ -76,6 +76,8 @@ int dw_pcie_cfg_read(void __iomem *addr, int size,
>> u32 *val);
>> int dw_pcie_cfg_write(void __iomem *addr, int size, u32 val);
>> irqreturn_t dw_handle_msi_irq(struct pcie_port *pp);
>> void dw_pcie_msi_init(struct pcie_port *pp);
>> +int dw_pcie_check_link_is_up(struct pcie_port *pp, int max_ret, int
>> sleep_min,
>> + int sleep_max);
>> int dw_pcie_link_up(struct pcie_port *pp);
>> void dw_pcie_setup_rc(struct pcie_port *pp);
>> int dw_pcie_host_init(struct pcie_port *pp);
>> diff --git a/drivers/pci/host/pcie-spear13xx.c b/drivers/pci/host/pcie-
>> spear13xx.c
>> index b95b756..5c24595 100644
>> --- a/drivers/pci/host/pcie-spear13xx.c
>> +++ b/drivers/pci/host/pcie-spear13xx.c
>> @@ -13,7 +13,6 @@
>> */
>>
>> #include <linux/clk.h>
>> -#include <linux/delay.h>
>> #include <linux/interrupt.h>
>> #include <linux/kernel.h>
>> #include <linux/module.h>
>> @@ -149,7 +148,6 @@ static int spear13xx_pcie_establish_link(struct
>> pcie_port *pp)
>> struct spear13xx_pcie *spear13xx_pcie = to_spear13xx_pcie(pp);
>> struct pcie_app_reg *app_reg = spear13xx_pcie->app_base;
>> u32 exp_cap_off = EXP_CAP_ID_OFFSET;
>> - unsigned int retries;
>>
>> if (dw_pcie_link_up(pp)) {
>> dev_err(pp->dev, "link already up\n");
>> @@ -201,15 +199,9 @@ static int spear13xx_pcie_establish_link(struct
>> pcie_port *pp)
>> &app_reg->app_ctrl_0);
>>
>> /* check if the link is up or not */
>> - for (retries = 0; retries < 10; retries++) {
>> - if (dw_pcie_link_up(pp)) {
>> - dev_info(pp->dev, "link up\n");
>> - return 0;
>> - }
>> - mdelay(100);
>> - }
>> + if (!dw_pcie_check_link_is_up(pp, 10, 100000, 110000))
>> + return 0;
>>
>> - dev_err(pp->dev, "link Fail\n");
>> return -EINVAL;
>> }
>>
>> --
>> 1.8.1.5
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
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Next message: Paolo Bonzini: "Re: [PATCH 2/2] KVM: x86: allow BSP to handle INIT IPIs like APs do"
Previous message: Andy Shevchenko: "Re: [PATCH 1/2] Staging:iio:Prefer using BIT macro"
In reply to: Gabriele Paoloni: "RE: [PATCH] link up validation moved to pcie-designware"
Next in thread: Gabriele Paoloni: "RE: [PATCH] link up validation moved to pcie-designware"
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