[v2] Revert "PCI: armada8k: Add support for gpio controlled reset signal"
diff mbox series

Message ID fac224459214193f89bbfdc0d058879ace50fe2c.1548366165.git.baruch@tkos.co.il
State Mainlined, archived
Commit f14bcc0add3abecceca1a3fe538c4ec9566893f3
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  • [v2] Revert "PCI: armada8k: Add support for gpio controlled reset signal"
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Commit Message

Baruch Siach Jan. 24, 2019, 9:42 p.m. UTC
This reverts commit 3d71746c420c1c1c27cf5c4e48f8fa0a6cfdc185.

That commit breaks boot on Macchiatobin when a Mellanox NIC is in the
PCIe slot.

It turns out that full reset cycle requires first comphy serdes
initialization. Reset signal toggle without comphy initialization makes
access to PCI configuration registers stall indefinitely. U-Boot toggles
the Macchiatobin PCIe reset line already at boot, after initializing the
comphy serdes.

So while commit 3d71746c42 ("PCI: armada8k: Add support for gpio
controlled reset signal") enables PCIe on platforms that U-Boot does
not (yet) touch the reset line (like Clearfog GT-8K), it breaks PCIe
(and boot) on the Macchiatobin.

Revert commit 3d71746c42 ("PCI: armada8k: Add support for gpio
controlled reset signal") entirely for now to fix the Macchaitobin
regression. Proper PCIe reset support would require PCIe comphy setup
support. That must wait for another kernel release.

Reported-by: Sven Auhagen <sven.auhagen@voleatech.de>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
v2: Add commit title to commit id mentions
---
 drivers/pci/controller/dwc/pcie-armada8k.c | 16 ----------------
 1 file changed, 16 deletions(-)

Comments

Lorenzo Pieralisi Jan. 25, 2019, 11:58 a.m. UTC | #1
On Thu, Jan 24, 2019 at 11:42:45PM +0200, Baruch Siach wrote:
> This reverts commit 3d71746c420c1c1c27cf5c4e48f8fa0a6cfdc185.
> 
> That commit breaks boot on Macchiatobin when a Mellanox NIC is in the
> PCIe slot.
> 
> It turns out that full reset cycle requires first comphy serdes
> initialization. Reset signal toggle without comphy initialization makes
> access to PCI configuration registers stall indefinitely. U-Boot toggles
> the Macchiatobin PCIe reset line already at boot, after initializing the
> comphy serdes.
> 
> So while commit 3d71746c42 ("PCI: armada8k: Add support for gpio
> controlled reset signal") enables PCIe on platforms that U-Boot does
> not (yet) touch the reset line (like Clearfog GT-8K), it breaks PCIe
> (and boot) on the Macchiatobin.

I have applied it and will send it upstream but please do test
changes and make sure u-boot configurations are consistent, this
commit log does not look promising in that respect.

Thanks,
Lorenzo

> Revert commit 3d71746c42 ("PCI: armada8k: Add support for gpio
> controlled reset signal") entirely for now to fix the Macchaitobin
> regression. Proper PCIe reset support would require PCIe comphy setup
> support. That must wait for another kernel release.
> 
> Reported-by: Sven Auhagen <sven.auhagen@voleatech.de>
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>
> ---
> v2: Add commit title to commit id mentions
> ---
>  drivers/pci/controller/dwc/pcie-armada8k.c | 16 ----------------
>  1 file changed, 16 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c
> index b171b6bc15c8..0c389a30ef5d 100644
> --- a/drivers/pci/controller/dwc/pcie-armada8k.c
> +++ b/drivers/pci/controller/dwc/pcie-armada8k.c
> @@ -22,7 +22,6 @@
>  #include <linux/resource.h>
>  #include <linux/of_pci.h>
>  #include <linux/of_irq.h>
> -#include <linux/gpio/consumer.h>
>  
>  #include "pcie-designware.h"
>  
> @@ -30,7 +29,6 @@ struct armada8k_pcie {
>  	struct dw_pcie *pci;
>  	struct clk *clk;
>  	struct clk *clk_reg;
> -	struct gpio_desc *reset_gpio;
>  };
>  
>  #define PCIE_VENDOR_REGS_OFFSET		0x8000
> @@ -139,12 +137,6 @@ static int armada8k_pcie_host_init(struct pcie_port *pp)
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
>  	struct armada8k_pcie *pcie = to_armada8k_pcie(pci);
>  
> -	if (pcie->reset_gpio) {
> -		/* assert and then deassert the reset signal */
> -		gpiod_set_value_cansleep(pcie->reset_gpio, 1);
> -		msleep(100);
> -		gpiod_set_value_cansleep(pcie->reset_gpio, 0);
> -	}
>  	dw_pcie_setup_rc(pp);
>  	armada8k_pcie_establish_link(pcie);
>  
> @@ -257,14 +249,6 @@ static int armada8k_pcie_probe(struct platform_device *pdev)
>  		goto fail_clkreg;
>  	}
>  
> -	/* Get reset gpio signal and hold asserted (logically high) */
> -	pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> -						   GPIOD_OUT_HIGH);
> -	if (IS_ERR(pcie->reset_gpio)) {
> -		ret = PTR_ERR(pcie->reset_gpio);
> -		goto fail_clkreg;
> -	}
> -
>  	platform_set_drvdata(pdev, pcie);
>  
>  	ret = armada8k_add_pcie_port(pcie, pdev);
> -- 
> 2.20.1
>

Patch
diff mbox series

diff --git a/drivers/pci/controller/dwc/pcie-armada8k.c b/drivers/pci/controller/dwc/pcie-armada8k.c
index b171b6bc15c8..0c389a30ef5d 100644
--- a/drivers/pci/controller/dwc/pcie-armada8k.c
+++ b/drivers/pci/controller/dwc/pcie-armada8k.c
@@ -22,7 +22,6 @@ 
 #include <linux/resource.h>
 #include <linux/of_pci.h>
 #include <linux/of_irq.h>
-#include <linux/gpio/consumer.h>
 
 #include "pcie-designware.h"
 
@@ -30,7 +29,6 @@  struct armada8k_pcie {
 	struct dw_pcie *pci;
 	struct clk *clk;
 	struct clk *clk_reg;
-	struct gpio_desc *reset_gpio;
 };
 
 #define PCIE_VENDOR_REGS_OFFSET		0x8000
@@ -139,12 +137,6 @@  static int armada8k_pcie_host_init(struct pcie_port *pp)
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct armada8k_pcie *pcie = to_armada8k_pcie(pci);
 
-	if (pcie->reset_gpio) {
-		/* assert and then deassert the reset signal */
-		gpiod_set_value_cansleep(pcie->reset_gpio, 1);
-		msleep(100);
-		gpiod_set_value_cansleep(pcie->reset_gpio, 0);
-	}
 	dw_pcie_setup_rc(pp);
 	armada8k_pcie_establish_link(pcie);
 
@@ -257,14 +249,6 @@  static int armada8k_pcie_probe(struct platform_device *pdev)
 		goto fail_clkreg;
 	}
 
-	/* Get reset gpio signal and hold asserted (logically high) */
-	pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset",
-						   GPIOD_OUT_HIGH);
-	if (IS_ERR(pcie->reset_gpio)) {
-		ret = PTR_ERR(pcie->reset_gpio);
-		goto fail_clkreg;
-	}
-
 	platform_set_drvdata(pdev, pcie);
 
 	ret = armada8k_add_pcie_port(pcie, pdev);