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

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Message-ID: <alpine.DEB.2.02.1601181533010.16178@kaball.uk.xensource.com>
Date:	Mon, 18 Jan 2016 15:41:03 +0000
From:	Stefano Stabellini <stefano.stabellini@...citrix.com>
To:	Shannon Zhao <zhaoshenglong@...wei.com>
CC:	<linux-arm-kernel@...ts.infradead.org>,
	<ard.biesheuvel@...aro.org>, <stefano.stabellini@...rix.com>,
	<david.vrabel@...rix.com>, <mark.rutland@....com>,
	<devicetree@...r.kernel.org>, <linux-efi@...r.kernel.org>,
	<catalin.marinas@....com>, <will.deacon@....com>,
	<linux-kernel@...r.kernel.org>, <xen-devel@...ts.xen.org>,
	<julien.grall@...rix.com>, <shannon.zhao@...aro.org>,
	<peter.huangpeng@...wei.com>, <matt@...eblueprint.co.uk>
Subject: Re: [Xen-devel] [PATCH v2 14/16] Xen: EFI: Parse DT parameters for
 Xen specific UEFI

CC'ing Matt Fleming

On Fri, 15 Jan 2016, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@...aro.org>
> 
> 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@...aro.org>

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.

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.


> +			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
> 
> 
> 
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