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openwrtv4/target/linux/brcm2708/patches-4.4/0223-Revert-bcm2835-sdhost-Precalc-divisors-and-overclock.patch
Álvaro Fernández Rojas 011f2c26f1 brcm2708: update linux 4.4 patches to latest version 
As usual these patches were extracted and rebased from the raspberry pi repo:
https://github.com/raspberrypi/linux/tree/rpi-4.4.y

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2016-12-04 12:32:04 +01:00

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From cc8d551542116bd779ee2ceb63746324bc3732ed Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Mon, 4 Apr 2016 12:35:32 +0100
Subject: [PATCH] Revert "bcm2835-sdhost: Precalc divisors and overclocks"
This reverts commit 20260462773366a5734e5268dae0a4c179a21a2d.
---
drivers/mmc/host/bcm2835-sdhost.c | 152 ++++++++++++++++----------------------
1 file changed, 64 insertions(+), 88 deletions(-)
--- a/drivers/mmc/host/bcm2835-sdhost.c
+++ b/drivers/mmc/host/bcm2835-sdhost.c
@@ -154,15 +154,12 @@ struct bcm2835_host {
u32 pio_timeout; /* In jiffies */
int clock; /* Current clock speed */
- int clocks[2];
bool slow_card; /* Force 11-bit divisor */
unsigned int max_clk; /* Max src clock freq */
- unsigned int src_clks[2]; /* Min/max src clock freqs */
- unsigned int cur_clk_idx; /* Index of current clock */
- unsigned int next_clk_idx; /* Next clock index */
- unsigned int cdivs[2];
+ unsigned int min_clk; /* Min src clock freq */
+ unsigned int cur_clk; /* Current src clock freq */
struct tasklet_struct finish_tasklet; /* Tasklet structures */
@@ -216,7 +213,7 @@ struct bcm2835_host {
u32 delay_after_stop; /* minimum time between stop and subsequent data transfer */
u32 delay_after_this_stop; /* minimum time between this stop and subsequent data transfer */
u32 overclock_50; /* frequency to use when 50MHz is requested (in MHz) */
- u32 prev_overclock_50;
+ u32 overclock; /* Current frequency if overclocked, else zero */
u32 pio_limit; /* Maximum block count for PIO (0 = always DMA) */
u32 sectors; /* Cached card size in sectors */
@@ -1512,35 +1509,10 @@ static irqreturn_t bcm2835_sdhost_irq(in
return result;
}
-static void bcm2835_sdhost_select_clock(struct bcm2835_host *host, int idx)
-{
- unsigned int clock = host->clocks[idx];
- unsigned int cdiv = host->cdivs[idx];
-
- host->mmc->actual_clock = clock;
- host->ns_per_fifo_word = (1000000000/clock) *
- ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
-
- host->cdiv = cdiv;
- bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
-
- /* Set the timeout to 500ms */
- bcm2835_sdhost_write(host, clock/2, SDTOUT);
-
- host->cur_clk_idx = host->next_clk_idx = idx;
-
- if (host->debug)
- pr_info("%s: clock=%d -> src_clk=%d, cdiv=%x (actual %d)\n",
- mmc_hostname(host->mmc), host->clock,
- host->src_clks[idx], host->cdiv,
- host->mmc->actual_clock);
-}
-
void bcm2835_sdhost_set_clock(struct bcm2835_host *host)
{
int div = 0; /* Initialized for compiler warning */
unsigned int clock = host->clock;
- int clk_idx;
if (host->debug)
pr_info("%s: set_clock(%d)\n", mmc_hostname(host->mmc), clock);
@@ -1581,45 +1553,53 @@ void bcm2835_sdhost_set_clock(struct bcm
return;
}
- /* Calculate the clock divisors */
- for (clk_idx = 0; clk_idx <= host->variable_clock; clk_idx++)
- {
- unsigned int cur_clk = host->src_clks[clk_idx];
- unsigned int actual_clock;
+ div = host->cur_clk / clock;
+ if (div < 2)
+ div = 2;
+ if ((host->cur_clk / div) > clock)
+ div++;
+ div -= 2;
+
+ if (div > SDCDIV_MAX_CDIV)
+ div = SDCDIV_MAX_CDIV;
+
+ clock = host->cur_clk / (div + 2);
+ host->mmc->actual_clock = clock;
+
+ /* Calibrate some delays */
+
+ host->ns_per_fifo_word = (1000000000/clock) *
+ ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
- div = cur_clk / clock;
- if (div < 2)
- div = 2;
- if ((cur_clk / div) > clock)
- div++;
- div -= 2;
-
- if (div > SDCDIV_MAX_CDIV)
- div = SDCDIV_MAX_CDIV;
- actual_clock = cur_clk / (div + 2);
-
- host->cdivs[clk_idx] = div;
- host->clocks[clk_idx] = actual_clock;
-
- if (host->overclock_50 != host->prev_overclock_50) {
- const char *clk_name = "";
- if (host->variable_clock)
- clk_name = clk_idx ? " (turbo)" : " (normal)";
- if (actual_clock > host->clock)
- pr_info("%s: overclocking to %dHz%s\n",
- mmc_hostname(host->mmc),
- actual_clock, clk_name);
- else if ((host->overclock_50 < 50) && (clk_idx == 0))
- pr_info("%s: cancelling overclock%s\n",
- mmc_hostname(host->mmc),
- host->variable_clock ? "s" : "");
+ if (clock > host->clock) {
+ /* Save the closest value, to make it easier
+ to reduce in the event of error */
+ host->overclock_50 = (clock/MHZ);
+
+ if (clock != host->overclock) {
+ pr_warn("%s: overclocking to %dHz\n",
+ mmc_hostname(host->mmc), clock);
+ host->overclock = clock;
}
}
+ else if (host->overclock)
+ {
+ host->overclock = 0;
+ if (clock == 50 * MHZ)
+ pr_warn("%s: cancelling overclock\n",
+ mmc_hostname(host->mmc));
+ }
- if (host->clock == 50*MHZ)
- host->prev_overclock_50 = host->overclock_50;
+ host->cdiv = div;
+ bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
- bcm2835_sdhost_select_clock(host, host->cur_clk_idx);
+ /* Set the timeout to 500ms */
+ bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
+
+ if (host->debug)
+ pr_info("%s: clock=%d -> cur_clk=%d, cdiv=%x (actual clock %d)\n",
+ mmc_hostname(host->mmc), host->clock,
+ host->cur_clk, host->cdiv, host->mmc->actual_clock);
}
static void bcm2835_sdhost_request(struct mmc_host *mmc, struct mmc_request *mrq)
@@ -1677,9 +1657,6 @@ static void bcm2835_sdhost_request(struc
spin_lock_irqsave(&host->lock, flags);
- if (host->next_clk_idx != host->cur_clk_idx)
- bcm2835_sdhost_select_clock(host, host->next_clk_idx);
-
WARN_ON(host->mrq != NULL);
host->mrq = mrq;
@@ -1742,7 +1719,11 @@ static int bcm2835_sdhost_cpufreq_callba
return NOTIFY_BAD;
break;
case CPUFREQ_POSTCHANGE:
- host->next_clk_idx = (freq->new > freq->old);
+ if (freq->new > freq->old)
+ host->cur_clk = host->max_clk;
+ else
+ host->cur_clk = host->min_clk;
+ bcm2835_sdhost_set_clock(host);
up(&host->cpufreq_semaphore);
break;
default:
@@ -1782,11 +1763,8 @@ static void bcm2835_sdhost_set_ios(struc
ios->clock, ios->power_mode, ios->bus_width,
ios->timing, ios->signal_voltage, ios->drv_type);
- if (ios->clock && (host->cur_clk_idx == -1)) {
- unsigned int cur_clk =
- get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
- host->cur_clk_idx = (cur_clk == host->src_clks[0]) ? 0 : 1;
- }
+ if (ios->clock && !host->cur_clk)
+ host->cur_clk = get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
spin_lock_irqsave(&host->lock, flags);
@@ -1876,12 +1854,11 @@ static void bcm2835_sdhost_tasklet_finis
/* Drop the overclock after any data corruption, or after any
error overclocked */
- if (host->clock > 50*MHZ) {
+ if (host->overclock) {
if ((mrq->cmd && mrq->cmd->error) ||
(mrq->data && mrq->data->error) ||
(mrq->stop && mrq->stop->error)) {
- host->overclock_50 = (host->clock/MHZ) - 1;
-
+ host->overclock_50--;
pr_warn("%s: reducing overclock due to errors\n",
mmc_hostname(host->mmc));
bcm2835_sdhost_set_clock(host);
@@ -2045,7 +2022,7 @@ static int bcm2835_sdhost_probe(struct p
struct bcm2835_host *host;
struct mmc_host *mmc;
const __be32 *addr;
- unsigned int max_clk, min_clk;
+ unsigned int max_clk;
int ret;
pr_debug("bcm2835_sdhost_probe\n");
@@ -2151,8 +2128,12 @@ static int bcm2835_sdhost_probe(struct p
else
mmc->caps |= MMC_CAP_4_BIT_DATA;
+ ret = bcm2835_sdhost_add_host(host);
+ if (ret)
+ goto err;
+
/* Query the core clock frequencies */
- min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
+ host->min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
max_clk = get_core_clock(RPI_FIRMWARE_GET_MAX_CLOCK_RATE);
if (max_clk != host->max_clk) {
pr_warn("%s: Expected max clock %d, found %d\n",
@@ -2160,24 +2141,19 @@ static int bcm2835_sdhost_probe(struct p
host->max_clk = max_clk;
}
- host->src_clks[0] = min_clk;
- host->cur_clk_idx = -1;
- if (max_clk != min_clk) {
- host->src_clks[1] = max_clk;
+ if (host->min_clk != host->max_clk) {
host->cpufreq_nb.notifier_call =
bcm2835_sdhost_cpufreq_callback;
sema_init(&host->cpufreq_semaphore, 1);
cpufreq_register_notifier(&host->cpufreq_nb,
CPUFREQ_TRANSITION_NOTIFIER);
host->variable_clock = 1;
+ host->cur_clk = 0; /* Get this later */
} else {
host->variable_clock = 0;
+ host->cur_clk = host->max_clk;
}
- ret = bcm2835_sdhost_add_host(host);
- if (ret)
- goto err;
-
platform_set_drvdata(pdev, host);
pr_debug("bcm2835_sdhost_probe -> OK\n");
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