diff options
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.patch | 226 |
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, |