Re: [Xen-devel] [PATCH v2 14/16] Xen: EFI: Parse DT parameters for Xen specific UEFI

[Shannon Zhao]

On 2016/1/18 23:41, Stefano Stabellini wrote:
> CC'ing Matt Fleming
>
> On Fri, 15 Jan 2016, Shannon Zhao wrote:
> > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> >
> > Add a new function to parse DT parameters for Xen specific UEFI just
> > like the way for normal UEFI. Then it could reuse the existing codes.
> >
> > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
>
> Please CC the maintainers, use ./scripts/get_maintainer.pl to find out
> who they are.
>
>
> >   drivers/firmware/efi/efi.c | 45 ++++++++++++++++++++++++++++++++++++++-------
> >   1 file changed, 38 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
> > index 027ca21..2dbc2ac 100644
> > --- a/drivers/firmware/efi/efi.c
> > +++ b/drivers/firmware/efi/efi.c
> > @@ -24,6 +24,7 @@
> >   #include <linux/of_fdt.h>
> >   #include <linux/io.h>
> >   #include <linux/platform_device.h>
> > +#include <xen/xen.h>
> >
> >   struct efi __read_mostly efi = {
> >   	.mps			= EFI_INVALID_TABLE_ADDR,
> > @@ -498,12 +499,14 @@ device_initcall(efi_load_efivars);
> >   		FIELD_SIZEOF(struct efi_fdt_params, field) \
> >   	}
> >
> > -static __initdata struct {
> > +struct params {
> >   	const char name[32];
> >   	const char propname[32];
> >   	int offset;
> >   	int size;
> > -} dt_params[] = {
> > +};
> > +
> > +static struct params fdt_params[] __initdata = {
> >   	UEFI_PARAM("System Table", "linux,uefi-system-table", system_table),
> >   	UEFI_PARAM("MemMap Address", "linux,uefi-mmap-start", mmap),
> >   	UEFI_PARAM("MemMap Size", "linux,uefi-mmap-size", mmap_size),
> > @@ -511,6 +514,14 @@ static __initdata struct {
> >   	UEFI_PARAM("MemMap Desc. Version", "linux,uefi-mmap-desc-ver", desc_ver)
> >   };
> >
> > +static struct params xen_fdt_params[] __initdata = {
> > +	UEFI_PARAM("System Table", "xen,uefi-system-table", system_table),
> > +	UEFI_PARAM("MemMap Address", "xen,uefi-mmap-start", mmap),
> > +	UEFI_PARAM("MemMap Size", "xen,uefi-mmap-size", mmap_size),
> > +	UEFI_PARAM("MemMap Desc. Size", "xen,uefi-mmap-desc-size", desc_size),
> > +	UEFI_PARAM("MemMap Desc. Version", "xen,uefi-mmap-desc-ver", desc_ver)
> > +};
> > +
> >   struct param_info {
> >   	int found;
> >   	void *params;
> > @@ -520,15 +531,28 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
> >   				       int depth, void *data)
> >   {
> >   	struct param_info *info = data;
> > +	struct params *dt_params;
> > +	unsigned int size;
> >   	const void *prop;
> >   	void *dest;
> >   	u64 val;
> >   	int i, len;
> >
> > -	if (depth != 1 || strcmp(uname, "chosen") != 0)
> > -		return 0;
> > +	if (efi_enabled(EFI_PARAVIRT)) {
> > +		if (depth != 2 || strcmp(uname, "uefi") != 0)
>
> You are already introducing this check in the previous patch when
> setting EFI_PARAVIRT, why do this again now?  But if we need to do this
> check again, then, like Mark suggested, it should be done against the
> full path.
This check just wants to confirm that the current node is the "uefi" 
node and we can parse it with xen_fdt_params now.

> Also you added below to efi_get_fdt_params:
>
> 	if (efi_enabled(EFI_PARAVIRT))
> 		dt_params = xen_fdt_params;
> 	else
> 		dt_params = fdt_params;
>
> efi_get_fdt_params is the sole caller of fdt_find_uefi_params: it makes
> sense to set dt_params only once, then pass it to fdt_find_uefi_params
> as parameter.
Sure.
> > +			return 0;
> >
> > -	for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
> > +		dt_params = xen_fdt_params;
> > +		size = ARRAY_SIZE(xen_fdt_params);
> > +	} else {
> > +		if (depth != 1 || strcmp(uname, "chosen") != 0)
> > +			return 0;
> > +
> > +		dt_params = fdt_params;
> > +		size = ARRAY_SIZE(fdt_params);
> > +	}
> > +
> > +	for (i = 0; i < size; i++) {
> >   		prop = of_get_flat_dt_prop(node, dt_params[i].propname, &len);
> >   		if (!prop)
> >   			return 0;
> > @@ -552,6 +576,7 @@ static int __init fdt_find_uefi_params(unsigned long node, const char *uname,
> >   int __init efi_get_fdt_params(struct efi_fdt_params *params)
> >   {
> >   	struct param_info info;
> > +	struct params *dt_params;
> >   	int ret;
> >
> >   	pr_info("Getting EFI parameters from FDT:\n");
> > @@ -559,12 +584,18 @@ int __init efi_get_fdt_params(struct efi_fdt_params *params)
> >   	info.found = 0;
> >   	info.params = params;
> >
> > +	if (efi_enabled(EFI_PARAVIRT))
> > +		dt_params = xen_fdt_params;
> > +	else
> > +		dt_params = fdt_params;
> > +
> >   	ret = of_scan_flat_dt(fdt_find_uefi_params, &info);
> > -	if (!info.found)
> > +	if (!info.found) {
> >   		pr_info("UEFI not found.\n");
> > -	else if (!ret)
> > +	} else if (!ret) {
> >   		pr_err("Can't find '%s' in device tree!\n",
> >   		       dt_params[info.found].name);
> > +	}
> >
> >   	return ret;
> >   }
> > --
> > 2.0.4
> >
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel

--
Shannon