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Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0227-bcm2835-sdhost-Firmware-manages-the-clock-divisor.patch')
-rw-r--r--target/linux/brcm2708/patches-4.4/0227-bcm2835-sdhost-Firmware-manages-the-clock-divisor.patch226
1 files changed, 226 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0227-bcm2835-sdhost-Firmware-manages-the-clock-divisor.patch b/target/linux/brcm2708/patches-4.4/0227-bcm2835-sdhost-Firmware-manages-the-clock-divisor.patch
new file mode 100644
index 0000000000..828692dd9d
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0227-bcm2835-sdhost-Firmware-manages-the-clock-divisor.patch
@@ -0,0 +1,226 @@
+From 08532d242d7702ae0add95096aa49c5e96e066e2 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.org>
+Date: Mon, 4 Apr 2016 16:03:18 +0100
+Subject: [PATCH 227/232] bcm2835-sdhost: Firmware manages the clock divisor
+
+The bcm2835-sdhost driver hands control of the CDIV clock divisor
+register to matching firmware, allowing it to adjust to a changing
+core clock. This removes the need to use the performance governor or
+to enable io_is_busy on the on-demand governor in order to get the
+best SD performance.
+
+N.B. As SD clocks must be an integer divisor of the core clock, it is
+possible that the SD clock for "turbo" mode can be different (even
+lower) than "normal" mode.
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.org>
+---
+ drivers/mmc/host/bcm2835-sdhost.c | 120 ++++++++++++++++++-----------
+ include/soc/bcm2835/raspberrypi-firmware.h | 1 +
+ 2 files changed, 74 insertions(+), 47 deletions(-)
+
+--- a/drivers/mmc/host/bcm2835-sdhost.c
++++ b/drivers/mmc/host/bcm2835-sdhost.c
+@@ -50,6 +50,7 @@
+ #include <linux/of_dma.h>
+ #include <linux/time.h>
+ #include <linux/workqueue.h>
++#include <soc/bcm2835/raspberrypi-firmware.h>
+
+ #define DRIVER_NAME "sdhost-bcm2835"
+
+@@ -183,6 +184,7 @@ struct bcm2835_host {
+ unsigned int use_sbc:1; /* Send CMD23 */
+
+ unsigned int debug:1; /* Enable debug output */
++ unsigned int firmware_sets_cdiv:1; /* Let the firmware manage the clock */
+
+ /*DMA part*/
+ struct dma_chan *dma_chan_rxtx; /* DMA channel for reads and writes */
+@@ -430,7 +432,7 @@ static void bcm2835_sdhost_reset_interna
+ host->clock = 0;
+ host->sectors = 0;
+ bcm2835_sdhost_write(host, host->hcfg, SDHCFG);
+- bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
++ bcm2835_sdhost_write(host, SDCDIV_MAX_CDIV, SDCDIV);
+ mmiowb();
+ }
+
+@@ -1534,62 +1536,75 @@ void bcm2835_sdhost_set_clock(struct bcm
+
+ host->mmc->actual_clock = 0;
+
+- if (clock < 100000) {
+- /* Can't stop the clock, but make it as slow as possible
+- * to show willing
+- */
+- host->cdiv = SDCDIV_MAX_CDIV;
+- bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
+- return;
+- }
+-
+- div = host->max_clk / clock;
+- if (div < 2)
+- div = 2;
+- if ((host->max_clk / div) > clock)
+- div++;
+- div -= 2;
++ if (host->firmware_sets_cdiv) {
++ u32 msg[3] = { clock, 0, 0 };
+
+- if (div > SDCDIV_MAX_CDIV)
+- div = SDCDIV_MAX_CDIV;
++ rpi_firmware_property(rpi_firmware_get(NULL),
++ RPI_FIRMWARE_SET_SDHOST_CLOCK,
++ &msg, sizeof(msg));
+
+- clock = host->max_clk / (div + 2);
+- host->mmc->actual_clock = clock;
++ clock = max(msg[1], msg[2]);
++ } else {
++ if (clock < 100000) {
++ /* Can't stop the clock, but make it as slow as
++ * possible to show willing
++ */
++ host->cdiv = SDCDIV_MAX_CDIV;
++ bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
++ return;
++ }
++
++ div = host->max_clk / clock;
++ if (div < 2)
++ div = 2;
++ if ((host->max_clk / div) > clock)
++ div++;
++ div -= 2;
++
++ if (div > SDCDIV_MAX_CDIV)
++ div = SDCDIV_MAX_CDIV;
++
++ clock = host->max_clk / (div + 2);
++
++ host->cdiv = div;
++ bcm2835_sdhost_write(host, host->cdiv, SDCDIV);
++
++ if (host->debug)
++ pr_info("%s: clock=%d -> max_clk=%d, cdiv=%x "
++ "(actual clock %d)\n",
++ mmc_hostname(host->mmc), input_clock,
++ host->max_clk, host->cdiv,
++ clock);
++ }
+
+ /* Calibrate some delays */
+
+ host->ns_per_fifo_word = (1000000000/clock) *
+ ((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
+
+- if (clock > input_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;
++ if (input_clock == 50 * MHZ) {
++ if (clock > input_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));
+ }
+ }
+- 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);
+
+ /* Set the timeout to 500ms */
+- bcm2835_sdhost_write(host, host->mmc->actual_clock/2, SDTOUT);
++ bcm2835_sdhost_write(host, clock/2, SDTOUT);
+
+- if (host->debug)
+- pr_info("%s: clock=%d -> max_clk=%d, cdiv=%x (actual clock %d)\n",
+- mmc_hostname(host->mmc), input_clock,
+- host->max_clk, host->cdiv, host->mmc->actual_clock);
++ host->mmc->actual_clock = clock;
+ }
+
+ static void bcm2835_sdhost_request(struct mmc_host *mmc, struct mmc_request *mrq)
+@@ -1704,11 +1719,6 @@ static void bcm2835_sdhost_set_ios(struc
+
+ log_event("IOS<", ios->clock, 0);
+
+- if (!ios->clock || ios->clock != host->clock) {
+- bcm2835_sdhost_set_clock(host, ios->clock);
+- host->clock = ios->clock;
+- }
+-
+ /* set bus width */
+ host->hcfg &= ~SDHCFG_WIDE_EXT_BUS;
+ if (ios->bus_width == MMC_BUS_WIDTH_4)
+@@ -1721,6 +1731,11 @@ static void bcm2835_sdhost_set_ios(struc
+
+ bcm2835_sdhost_write(host, host->hcfg, SDHCFG);
+
++ if (!ios->clock || ios->clock != host->clock) {
++ bcm2835_sdhost_set_clock(host, ios->clock);
++ host->clock = ios->clock;
++ }
++
+ mmiowb();
+
+ spin_unlock_irqrestore(&host->lock, flags);
+@@ -1953,6 +1968,7 @@ static int bcm2835_sdhost_probe(struct p
+ struct bcm2835_host *host;
+ struct mmc_host *mmc;
+ const __be32 *addr;
++ u32 msg[3];
+ int ret;
+
+ pr_debug("bcm2835_sdhost_probe\n");
+@@ -2058,6 +2074,16 @@ static int bcm2835_sdhost_probe(struct p
+ else
+ mmc->caps |= MMC_CAP_4_BIT_DATA;
+
++ msg[0] = 0;
++ msg[1] = ~0;
++ msg[2] = ~0;
++
++ rpi_firmware_property(rpi_firmware_get(NULL),
++ RPI_FIRMWARE_SET_SDHOST_CLOCK,
++ &msg, sizeof(msg));
++
++ host->firmware_sets_cdiv = (msg[1] != ~0);
++
+ ret = bcm2835_sdhost_add_host(host);
+ if (ret)
+ goto err;
+--- a/include/soc/bcm2835/raspberrypi-firmware.h
++++ b/include/soc/bcm2835/raspberrypi-firmware.h
+@@ -79,6 +79,7 @@ enum rpi_firmware_property_tag {
+ RPI_FIRMWARE_SET_VOLTAGE = 0x00038003,
+ RPI_FIRMWARE_SET_TURBO = 0x00038009,
+ RPI_FIRMWARE_SET_CUSTOMER_OTP = 0x00038021,
++ RPI_FIRMWARE_SET_SDHOST_CLOCK = 0x00038042,
+
+ /* Dispmanx TAGS */
+ RPI_FIRMWARE_FRAMEBUFFER_ALLOCATE = 0x00040001,