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Revision ab170c27361d1578b4769276ce2bbdb14394743d authored by Ondrej Jirman on 21 April 2018, 04:51:55 UTC, committed by Sean Paul on 25 April 2018, 19:03:12 UTC 
Revert "drm/sun4i: add lvds mode_valid function"
 
The reverted commit broke LVDS output on TBS A711 Tablet. That tablet
has simple-panel node that has fixed pixel clock-frequency that A83T
SoC used in the tablet can't generate exactly.

Requested rate is 52000000 and rounded_rate is calculated as 51857142.
It's close enough for it to work in practice, but with strict check
in the reverted commit, the mode is rejected needlessly in this case.

DT allows to specify a range of values for simple-panel/clock-frequency,
but driver doesn't respect that ATM. Given that TBS A711 is the single
user of sun4i-lvds driver, let's revert that commit for now, until
a better solution for the problem is found.

Also see: https://patchwork.kernel.org/patch/9446385/ for relevant
discussion (or search for "[RFC] drm/sun4i: rgb: Add 5% tolerance
to dot clock frequency check").

Fixes: e4e4b7ad50cf ("drm/sun4i: add lvds mode_valid function")
Reported-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180421045155.15332-1-megous@megous.com
Signed-off-by: Sean Paul <seanpaul@chromium.org>
1 parent 6d08b06
Raw File
dh_helper.c 
/*
 * Copyright (c) 2016, Intel Corporation
 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/string.h>
#include <crypto/dh.h>
#include <crypto/kpp.h>

#define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int))

static inline u8 *dh_pack_data(void *dst, const void *src, size_t size)
{
	memcpy(dst, src, size);
	return dst + size;
}

static inline const u8 *dh_unpack_data(void *dst, const void *src, size_t size)
{
	memcpy(dst, src, size);
	return src + size;
}

static inline unsigned int dh_data_size(const struct dh *p)
{
	return p->key_size + p->p_size + p->g_size;
}

unsigned int crypto_dh_key_len(const struct dh *p)
{
	return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p);
}
EXPORT_SYMBOL_GPL(crypto_dh_key_len);

int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params)
{
	u8 *ptr = buf;
	struct kpp_secret secret = {
		.type = CRYPTO_KPP_SECRET_TYPE_DH,
		.len = len
	};

	if (unlikely(!buf))
		return -EINVAL;

	if (len != crypto_dh_key_len(params))
		return -EINVAL;

	ptr = dh_pack_data(ptr, &secret, sizeof(secret));
	ptr = dh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
	ptr = dh_pack_data(ptr, &params->p_size, sizeof(params->p_size));
	ptr = dh_pack_data(ptr, &params->g_size, sizeof(params->g_size));
	ptr = dh_pack_data(ptr, params->key, params->key_size);
	ptr = dh_pack_data(ptr, params->p, params->p_size);
	dh_pack_data(ptr, params->g, params->g_size);

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_dh_encode_key);

int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params)
{
	const u8 *ptr = buf;
	struct kpp_secret secret;

	if (unlikely(!buf || len < DH_KPP_SECRET_MIN_SIZE))
		return -EINVAL;

	ptr = dh_unpack_data(&secret, ptr, sizeof(secret));
	if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH)
		return -EINVAL;

	ptr = dh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
	ptr = dh_unpack_data(&params->p_size, ptr, sizeof(params->p_size));
	ptr = dh_unpack_data(&params->g_size, ptr, sizeof(params->g_size));
	if (secret.len != crypto_dh_key_len(params))
		return -EINVAL;

	/*
	 * Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
	 * some drivers assume otherwise.
	 */
	if (params->key_size > params->p_size ||
	    params->g_size > params->p_size)
		return -EINVAL;

	/* Don't allocate memory. Set pointers to data within
	 * the given buffer
	 */
	params->key = (void *)ptr;
	params->p = (void *)(ptr + params->key_size);
	params->g = (void *)(ptr + params->key_size + params->p_size);

	/*
	 * Don't permit 'p' to be 0.  It's not a prime number, and it's subject
	 * to corner cases such as 'mod 0' being undefined or
	 * crypto_kpp_maxsize() returning 0.
	 */
	if (memchr_inv(params->p, 0, params->p_size) == NULL)
		return -EINVAL;

	return 0;
}
EXPORT_SYMBOL_GPL(crypto_dh_decode_key);
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