[U-Boot] [PATCH 2/2] efi: device path for nvme

[Patrick Wildt]

On Thu, Oct 03, 2019 at 03:12:45PM +0200, Heinrich Schuchardt wrote:
> On 10/3/19 1:02 PM, Patrick Wildt wrote:
> > This allows our EFI API to create a device path node for NVMe
> > devices.  It adds the necessary device path struct, uses the
> > nvme namespace accessor to retrieve the id and eui64, and also
> > provides support for the device path text protocol.
> > 
> > Signed-off-by: Patrick Wildt <patrick at blueri.se>
> > ---
> >   include/efi_api.h                        |  7 +++++++
> >   lib/efi_loader/efi_device_path.c         | 18 ++++++++++++++++++
> >   lib/efi_loader/efi_device_path_to_text.c | 13 +++++++++++++
> >   3 files changed, 38 insertions(+)
> > 
> > diff --git a/include/efi_api.h b/include/efi_api.h
> > index 37e56da460..22396172e1 100644
> > --- a/include/efi_api.h
> > +++ b/include/efi_api.h
> > @@ -422,6 +422,7 @@ struct efi_device_path_acpi_path {
> >   #  define DEVICE_PATH_SUB_TYPE_MSG_USB		0x05
> >   #  define DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR	0x0b
> >   #  define DEVICE_PATH_SUB_TYPE_MSG_USB_CLASS	0x0f
> > +#  define DEVICE_PATH_SUB_TYPE_MSG_NVME		0x17
> >   #  define DEVICE_PATH_SUB_TYPE_MSG_SD		0x1a
> >   #  define DEVICE_PATH_SUB_TYPE_MSG_MMC		0x1d
> > 
> > @@ -464,6 +465,12 @@ struct efi_device_path_sd_mmc_path {
> >   	u8 slot_number;
> >   } __packed;
> > 
> > +struct efi_device_path_nvme {
> > +	struct efi_device_path dp;
> > +	u32 ns_id;
> > +	u8 eui64[8];
> > +} __packed;
> > +
> >   #define DEVICE_PATH_TYPE_MEDIA_DEVICE		0x04
> >   #  define DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH	0x01
> >   #  define DEVICE_PATH_SUB_TYPE_CDROM_PATH	0x02
> > diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
> > index 86297bb7c1..6a18add269 100644
> > --- a/lib/efi_loader/efi_device_path.c
> > +++ b/lib/efi_loader/efi_device_path.c
> > @@ -10,6 +10,7 @@
> >   #include <dm.h>
> >   #include <usb.h>
> >   #include <mmc.h>
> > +#include <nvme.h>
> >   #include <efi_loader.h>
> >   #include <part.h>
> >   #include <sandboxblockdev.h>
> > @@ -451,6 +452,11 @@ static unsigned dp_size(struct udevice *dev)
> >   			return dp_size(dev->parent) +
> >   				sizeof(struct efi_device_path_sd_mmc_path);
> >   #endif
> > +#if defined(CONFIG_NVME)
> > +		case UCLASS_NVME:
> > +			return dp_size(dev->parent) +
> > +				sizeof(struct efi_device_path_nvme);
> > +#endif
> >   #ifdef CONFIG_SANDBOX
> >   		case UCLASS_ROOT:
> >   			 /*
> > @@ -583,6 +589,18 @@ static void *dp_fill(void *buf, struct udevice *dev)
> >   			sddp->slot_number = dev->seq;
> >   			return &sddp[1];
> >   			}
> > +#endif
> > +#if defined(CONFIG_NVME)
> > +		case UCLASS_NVME: {
> > +			struct efi_device_path_nvme *dp =
> > +				dp_fill(buf, dev->parent);
> > +
> > +			dp->dp.type     = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
> > +			dp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_NVME;
> > +			dp->dp.length   = sizeof(*dp);
> > +			nvme_get_namespace_id(dev, &dp->ns_id, &dp->eui64[0]);
> 
> Instead of &dp->eui64[0] you could simply write dp->eui64.
> To me that is easier to read.
> 
> Your code does not compile with GCC 9.2.1 (as available in Debian Bullseye):
> 
> lib/efi_loader/efi_device_path.c: In function ‘dp_fill’:
> lib/efi_loader/efi_device_path.c:601:31: error: taking address of packed
> member of ‘struct efi_device_path_nvme’ may result in an unaligned
> pointer value [-Werror=address-of-packed-member]
>   601 |    nvme_get_namespace_id(dev, &dp->ns_id, &dp->eui64[0]);
>       |                               ^~~~~~~~~~

Uh, that sounds bad.  How can we fix/work around this?  Maybe something
like..

u32 ns_id;
nvme_get_namespace_id(dev, &ns_id, &dp->eui64[0]);
memcpy(&dp->ns_id, &ns_id, sizeof(ns_id));

?

Best regards,
Patrick

> > +			return &dp[1];
> > +			}
> >   #endif
> >   		default:
> >   			debug("%s(%u) %s: unhandled parent class: %s (%u)\n",
> > diff --git a/lib/efi_loader/efi_device_path_to_text.c b/lib/efi_loader/efi_device_path_to_text.c
> > index 0f3796b373..e8a608bd07 100644
> > --- a/lib/efi_loader/efi_device_path_to_text.c
> > +++ b/lib/efi_loader/efi_device_path_to_text.c
> > @@ -148,6 +148,19 @@ static char *dp_msging(char *s, struct efi_device_path *dp)
> > 
> >   		break;
> >   	}
> > +	case DEVICE_PATH_SUB_TYPE_MSG_NVME: {
> > +		struct efi_device_path_nvme *ndp =
> > +			(struct efi_device_path_nvme *)dp;
> > +		int i;
> > +
> > +		s += sprintf(s, "NVME(0x%x,", ndp->ns_id);
> 
> In the spec this is "NVMe(",  i.e. lower case 'e' at the end.
> 
> > +		for (i = 0; i < sizeof(ndp->eui64); ++i)
> > +			s += sprintf(s, "%s%02x", i ? "-" : "",
> 
> The example in the spec uses capitalized hexadecimals in the example.
> But EDK2 uses lower case. So that should be ok.
> 
> Best regards
> 
> Heinrich
> 
> > +				     ndp->eui64[i]);
> > +		s += sprintf(s, ")");
> > +
> > +		break;
> > +	}
> >   	case DEVICE_PATH_SUB_TYPE_MSG_SD:
> >   	case DEVICE_PATH_SUB_TYPE_MSG_MMC: {
> >   		const char *typename =
> > 
>