mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-25 12:33:41 +00:00
68 lines
2 KiB
C
68 lines
2 KiB
C
|
// SPDX-License-Identifier: GPL-2.0+
|
||
|
|
/*
|
||
|
|
* (C) Copyright 2018 Cisco Systems, Inc.
|
||
|
|
*
|
||
|
|
* Author: Thomas Fitzsimmons <fitzsim@fitzsim.org>
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <common.h>
|
||
|
|
#include <mach/sdhci.h>
|
||
|
|
#include <malloc.h>
|
||
|
|
#include <sdhci.h>
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The BCMSTB SDHCI has a quirk in that its actual maximum frequency
|
||
|
|
* capability is 100 MHz. The divisor that is eventually written to
|
||
|
|
* SDHCI_CLOCK_CONTROL is calculated based on what the MMC device
|
||
|
|
* reports, and relative to this maximum frequency.
|
||
|
|
*
|
||
|
|
* This define used to be set to 52000000 (52 MHz), the desired
|
||
|
|
* maximum frequency, but that would result in the communication
|
||
|
|
* actually running at 100 MHz (seemingly without issue), which is
|
||
|
|
* out-of-spec.
|
||
|
|
*
|
||
|
|
* Now, by setting this to 0 (auto-detect), 100 MHz will be read from
|
||
|
|
* the capabilities register, and the resulting divisor will be
|
||
|
|
* doubled, meaning that the clock control register will be set to the
|
||
|
|
* in-spec 52 MHz value.
|
||
|
|
*/
|
||
|
|
#define BCMSTB_SDHCI_MAXIMUM_CLOCK_FREQUENCY 0
|
||
|
|
/*
|
||
|
|
* When the minimum clock frequency is set to 0 (auto-detect), U-Boot
|
||
|
|
* sets it to 100 MHz divided by SDHCI_MAX_DIV_SPEC_300, or 48,875 Hz,
|
||
|
|
* which results in the controller timing out when trying to
|
||
|
|
* communicate with the MMC device. Hard-code this value to 400000
|
||
|
|
* (400 kHz) to prevent this.
|
||
|
|
*/
|
||
|
|
#define BCMSTB_SDHCI_MINIMUM_CLOCK_FREQUENCY 400000
|
||
|
|
|
||
|
|
static char *BCMSTB_SDHCI_NAME = "bcmstb-sdhci";
|
||
|
|
|
||
|
|
/*
|
||
|
|
* This driver has only been tested with eMMC devices; SD devices may
|
||
|
|
* not work.
|
||
|
|
*/
|
||
|
|
int bcmstb_sdhci_init(phys_addr_t regbase)
|
||
|
|
{
|
||
|
|
struct sdhci_host *host = NULL;
|
||
|
|
|
||
|
|
host = (struct sdhci_host *)malloc(sizeof(struct sdhci_host));
|
||
|
|
if (!host) {
|
||
|
|
printf("%s: Failed to allocate memory\n", __func__);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
memset(host, 0, sizeof(*host));
|
||
|
|
|
||
|
|
host->name = BCMSTB_SDHCI_NAME;
|
||
|
|
host->ioaddr = (void *)regbase;
|
||
|
|
host->quirks = 0;
|
||
|
|
|
||
|
|
host->cfg.part_type = PART_TYPE_DOS;
|
||
|
|
|
||
|
|
host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
|
||
|
|
|
||
|
|
return add_sdhci(host,
|
||
|
|
BCMSTB_SDHCI_MAXIMUM_CLOCK_FREQUENCY,
|
||
|
|
BCMSTB_SDHCI_MINIMUM_CLOCK_FREQUENCY);
|
||
|
|
}
|