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pci: mx6: Implement reset callback

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Add a callback so that a board can implement it's own specific routine to
toggle the port's #PERST line or #define a GPIO to do so.

Signed-off-by: Marek Vasut <marex@denx.de>
This commit is contained in:
Marek Vasut 2014-02-03 21:46:22 +01:00 committed by Stefano Babic
parent 6d73c23410
commit bb01956344
1 changed files with 44 additions and 3 deletions
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47
drivers/pci/pcie_imx.c
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@ -15,6 +15,7 @@
#include <asm/arch/clock.h>
#include <asm/arch/iomux.h>
#include <asm/arch/crm_regs.h>
#include <asm/gpio.h>
#include <asm/io.h>
#include <asm/sizes.h>
#include <errno.h>
@ -450,6 +451,47 @@ static int imx6_pcie_init_phy(void)
return 0;
}
__weak int imx6_pcie_toggle_reset(void)
{
/*
* See 'PCI EXPRESS BASE SPECIFICATION, REV 3.0, SECTION 6.6.1'
* for detailed understanding of the PCIe CR reset logic.
*
* The PCIe #PERST reset line _MUST_ be connected, otherwise your
* design does not conform to the specification. You must wait at
* least 20 mS after de-asserting the #PERST so the EP device can
* do self-initialisation.
*
* In case your #PERST pin is connected to a plain GPIO pin of the
* CPU, you can define CONFIG_PCIE_IMX_PERST_GPIO in your board's
* configuration file and the condition below will handle the rest
* of the reset toggling.
*
* In case your #PERST toggling logic is more complex, for example
* connected via CPLD or somesuch, you can override this function
* in your board file and implement reset logic as needed. You must
* not forget to wait at least 20 mS after de-asserting #PERST in
* this case either though.
*
* In case your #PERST line of the PCIe EP device is not connected
* at all, your design is broken and you should fix your design,
* otherwise you will observe problems like for example the link
* not coming up after rebooting the system back from running Linux
* that uses the PCIe as well OR the PCIe link might not come up in
* Linux at all in the first place since it's in some non-reset
* state due to being previously used in U-Boot.
*/
#ifdef CONFIG_PCIE_IMX_PERST_GPIO
gpio_direction_output(CONFIG_PCIE_IMX_PERST_GPIO, 0);
mdelay(20);
gpio_set_value(CONFIG_PCIE_IMX_PERST_GPIO, 1);
mdelay(20);
#else
puts("WARNING: Make sure the PCIe #PERST line is connected!\n");
#endif
return 0;
}
static int imx6_pcie_deassert_core_reset(void)
{
struct iomuxc *iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
@ -466,10 +508,9 @@ static int imx6_pcie_deassert_core_reset(void)
* Wait for the clock to settle a bit, when the clock are sourced
* from the CPU, we need about 30mS to settle.
*/
mdelay(30);
mdelay(50);
/* FIXME: GPIO reset goes here */
mdelay(100);
imx6_pcie_toggle_reset();
return 0;
}