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Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0224-bcm2835-sdhost-Precalc-divisors-and-overclocks.patch')
-rw-r--r--target/linux/brcm2708/patches-4.4/0224-bcm2835-sdhost-Precalc-divisors-and-overclocks.patch270
1 files changed, 270 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0224-bcm2835-sdhost-Precalc-divisors-and-overclocks.patch b/target/linux/brcm2708/patches-4.4/0224-bcm2835-sdhost-Precalc-divisors-and-overclocks.patch
new file mode 100644
index 0000000000..14c2e8c861
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0224-bcm2835-sdhost-Precalc-divisors-and-overclocks.patch
@@ -0,0 +1,270 @@
+From 20260462773366a5734e5268dae0a4c179a21a2d Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Thu, 31 Mar 2016 15:44:53 +0100
+Subject: [PATCH 224/232] bcm2835-sdhost: Precalc divisors and overclocks
+
+Recalculating the clock divisors when the core clock changes is wasteful
+and makes it harder to manage the overclock settings. Instead,
+precalculate them and only report significant changes.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/mmc/host/bcm2835-sdhost.c | 152 ++++++++++++++++++++++----------------
+ 1 file changed, 88 insertions(+), 64 deletions(-)
+
+--- a/drivers/mmc/host/bcm2835-sdhost.c
++++ b/drivers/mmc/host/bcm2835-sdhost.c
+@@ -154,12 +154,15 @@ 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 min_clk; /* Min src clock freq */
+- unsigned int cur_clk; /* Current 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];
+
+ struct tasklet_struct finish_tasklet; /* Tasklet structures */
+
+@@ -213,7 +216,7 @@ 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 overclock; /* Current frequency if overclocked, else zero */
++ u32 prev_overclock_50;
+ u32 pio_limit; /* Maximum block count for PIO (0 = always DMA) */
+
+ u32 sectors; /* Cached card size in sectors */
+@@ -1509,10 +1512,35 @@ 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);
+@@ -1553,53 +1581,45 @@ void bcm2835_sdhost_set_clock(struct bcm
+ return;
+ }
+
+- 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);
++ /* 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;
+
+- 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;
++ 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" : "");
+ }
+ }
+- else if (host->overclock)
+- {
+- host->overclock = 0;
+- if (clock == 50 * MHZ)
+- pr_warn("%s: cancelling overclock\n",
+- mmc_hostname(host->mmc));
+- }
+
+- host->cdiv = div;
+- bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
++ if (host->clock == 50*MHZ)
++ host->prev_overclock_50 = host->overclock_50;
+
+- /* 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);
++ bcm2835_sdhost_select_clock(host, host->cur_clk_idx);
+ }
+
+ static void bcm2835_sdhost_request(struct mmc_host *mmc, struct mmc_request *mrq)
+@@ -1657,6 +1677,9 @@ 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;
+
+@@ -1719,11 +1742,7 @@ static int bcm2835_sdhost_cpufreq_callba
+ return NOTIFY_BAD;
+ break;
+ case CPUFREQ_POSTCHANGE:
+- if (freq->new > freq->old)
+- host->cur_clk = host->max_clk;
+- else
+- host->cur_clk = host->min_clk;
+- bcm2835_sdhost_set_clock(host);
++ host->next_clk_idx = (freq->new > freq->old);
+ up(&host->cpufreq_semaphore);
+ break;
+ default:
+@@ -1763,8 +1782,11 @@ 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)
+- host->cur_clk = get_core_clock(RPI_FIRMWARE_GET_CLOCK_RATE);
++ 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;
++ }
+
+ spin_lock_irqsave(&host->lock, flags);
+
+@@ -1854,11 +1876,12 @@ static void bcm2835_sdhost_tasklet_finis
+
+ /* Drop the overclock after any data corruption, or after any
+ error overclocked */
+- if (host->overclock) {
++ if (host->clock > 50*MHZ) {
+ if ((mrq->cmd && mrq->cmd->error) ||
+ (mrq->data && mrq->data->error) ||
+ (mrq->stop && mrq->stop->error)) {
+- host->overclock_50--;
++ host->overclock_50 = (host->clock/MHZ) - 1;
++
+ pr_warn("%s: reducing overclock due to errors\n",
+ mmc_hostname(host->mmc));
+ bcm2835_sdhost_set_clock(host);
+@@ -2022,7 +2045,7 @@ static int bcm2835_sdhost_probe(struct p
+ struct bcm2835_host *host;
+ struct mmc_host *mmc;
+ const __be32 *addr;
+- unsigned int max_clk;
++ unsigned int max_clk, min_clk;
+ int ret;
+
+ pr_debug("bcm2835_sdhost_probe\n");
+@@ -2128,12 +2151,8 @@ 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 */
+- host->min_clk = get_core_clock(RPI_FIRMWARE_GET_MIN_CLOCK_RATE);
++ 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",
+@@ -2141,19 +2160,24 @@ static int bcm2835_sdhost_probe(struct p
+ host->max_clk = max_clk;
+ }
+
+- if (host->min_clk != host->max_clk) {
++ host->src_clks[0] = min_clk;
++ host->cur_clk_idx = -1;
++ if (max_clk != min_clk) {
++ host->src_clks[1] = 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");