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
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>
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dh.c
/* Diffie-Hellman Key Agreement Method [RFC2631]
*
* 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/module.h>
#include <crypto/internal/kpp.h>
#include <crypto/kpp.h>
#include <crypto/dh.h>
#include <linux/mpi.h>
struct dh_ctx {
MPI p;
MPI g;
MPI xa;
};
static void dh_clear_ctx(struct dh_ctx *ctx)
{
mpi_free(ctx->p);
mpi_free(ctx->g);
mpi_free(ctx->xa);
memset(ctx, 0, sizeof(*ctx));
}
/*
* If base is g we compute the public key
* ya = g^xa mod p; [RFC2631 sec 2.1.1]
* else if base if the counterpart public key we compute the shared secret
* ZZ = yb^xa mod p; [RFC2631 sec 2.1.1]
*/
static int _compute_val(const struct dh_ctx *ctx, MPI base, MPI val)
{
/* val = base^xa mod p */
return mpi_powm(val, base, ctx->xa, ctx->p);
}
static inline struct dh_ctx *dh_get_ctx(struct crypto_kpp *tfm)
{
return kpp_tfm_ctx(tfm);
}
static int dh_check_params_length(unsigned int p_len)
{
return (p_len < 1536) ? -EINVAL : 0;
}
static int dh_set_params(struct dh_ctx *ctx, struct dh *params)
{
if (dh_check_params_length(params->p_size << 3))
return -EINVAL;
ctx->p = mpi_read_raw_data(params->p, params->p_size);
if (!ctx->p)
return -EINVAL;
ctx->g = mpi_read_raw_data(params->g, params->g_size);
if (!ctx->g)
return -EINVAL;
return 0;
}
static int dh_set_secret(struct crypto_kpp *tfm, const void *buf,
unsigned int len)
{
struct dh_ctx *ctx = dh_get_ctx(tfm);
struct dh params;
/* Free the old MPI key if any */
dh_clear_ctx(ctx);
if (crypto_dh_decode_key(buf, len, ¶ms) < 0)
goto err_clear_ctx;
if (dh_set_params(ctx, ¶ms) < 0)
goto err_clear_ctx;
ctx->xa = mpi_read_raw_data(params.key, params.key_size);
if (!ctx->xa)
goto err_clear_ctx;
return 0;
err_clear_ctx:
dh_clear_ctx(ctx);
return -EINVAL;
}
static int dh_compute_value(struct kpp_request *req)
{
struct crypto_kpp *tfm = crypto_kpp_reqtfm(req);
struct dh_ctx *ctx = dh_get_ctx(tfm);
MPI base, val = mpi_alloc(0);
int ret = 0;
int sign;
if (!val)
return -ENOMEM;
if (unlikely(!ctx->xa)) {
ret = -EINVAL;
goto err_free_val;
}
if (req->src) {
base = mpi_read_raw_from_sgl(req->src, req->src_len);
if (!base) {
ret = -EINVAL;
goto err_free_val;
}
} else {
base = ctx->g;
}
ret = _compute_val(ctx, base, val);
if (ret)
goto err_free_base;
ret = mpi_write_to_sgl(val, req->dst, req->dst_len, &sign);
if (ret)
goto err_free_base;
if (sign < 0)
ret = -EBADMSG;
err_free_base:
if (req->src)
mpi_free(base);
err_free_val:
mpi_free(val);
return ret;
}
static unsigned int dh_max_size(struct crypto_kpp *tfm)
{
struct dh_ctx *ctx = dh_get_ctx(tfm);
return mpi_get_size(ctx->p);
}
static void dh_exit_tfm(struct crypto_kpp *tfm)
{
struct dh_ctx *ctx = dh_get_ctx(tfm);
dh_clear_ctx(ctx);
}
static struct kpp_alg dh = {
.set_secret = dh_set_secret,
.generate_public_key = dh_compute_value,
.compute_shared_secret = dh_compute_value,
.max_size = dh_max_size,
.exit = dh_exit_tfm,
.base = {
.cra_name = "dh",
.cra_driver_name = "dh-generic",
.cra_priority = 100,
.cra_module = THIS_MODULE,
.cra_ctxsize = sizeof(struct dh_ctx),
},
};
static int dh_init(void)
{
return crypto_register_kpp(&dh);
}
static void dh_exit(void)
{
crypto_unregister_kpp(&dh);
}
module_init(dh_init);
module_exit(dh_exit);
MODULE_ALIAS_CRYPTO("dh");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("DH generic algorithm");
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