| Message ID | 1409058728-13347-4-git-send-email-tomeu.vizoso@collabora.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 08/26/2014 07:12 AM, Tomeu Vizoso wrote: > Sets the EMC clock rate based on the bandwidth requirements registered by > memory clients through the PM_QOS_MEMORY_BANDWIDTH class. > > Note: this is just an example and not a proper driver for a external memory > controller. Its only purpose is to illustrate how such a driver would set the > frequency of the external memory clock based on the bandwidth requirements of > memory clients. > diff --git a/arch/arm/mach-tegra/tegra.c b/arch/arm/mach-tegra/tegra.c > @@ -112,6 +117,11 @@ static void __init tegra_dt_init(void) > parent = soc_device_to_device(soc_dev); > > /* > + * HACK: register a platform device to probe the driver > + */ > + platform_device_register(&tegra_emc); I don't think this is a hack, except for the bug: That should only happen on Tegra124 not on all Tegra SoCs. Do you intend all 3 patches in this series to be merged? You'd mentioned you didn't when asked about this for a previous version. I'm not sure if that's changed? To merge, I'd need Thierry's ack on patch 2, and Thierry's, Peter's, Mikko's, and/or Tuomas's on this patch. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/26/2014 07:17 PM, Stephen Warren wrote: > On 08/26/2014 07:12 AM, Tomeu Vizoso wrote: >> Sets the EMC clock rate based on the bandwidth requirements registered by >> memory clients through the PM_QOS_MEMORY_BANDWIDTH class. >> >> Note: this is just an example and not a proper driver for a external >> memory >> controller. Its only purpose is to illustrate how such a driver would >> set the >> frequency of the external memory clock based on the bandwidth >> requirements of >> memory clients. > >> diff --git a/arch/arm/mach-tegra/tegra.c b/arch/arm/mach-tegra/tegra.c > >> @@ -112,6 +117,11 @@ static void __init tegra_dt_init(void) >> parent = soc_device_to_device(soc_dev); >> >> /* >> + * HACK: register a platform device to probe the driver >> + */ >> + platform_device_register(&tegra_emc); > > I don't think this is a hack, except for the bug: That should only > happen on Tegra124 not on all Tegra SoCs. > > Do you intend all 3 patches in this series to be merged? You'd mentioned > you didn't when asked about this for a previous version. I'm not sure if > that's changed? Yeah, I don't want 3/3 merged because we don't have a functional EMC clock yet on T124, and because I don't know yet where will be the best place to have that code in. That depends on Mikko's work on the real EMC driver which is in a bit of flux right now. I have kept posting it just because I think it complements nicely the explanation in the cover letter, but maybe confuses more than helps. Regards, Tomeu > To merge, I'd need Thierry's ack on patch 2, and Thierry's, Peter's, > Mikko's, and/or Tuomas's on this patch. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 08/27/2014 01:32 AM, Tomeu Vizoso wrote: > On 08/26/2014 07:17 PM, Stephen Warren wrote: >> On 08/26/2014 07:12 AM, Tomeu Vizoso wrote: >>> Sets the EMC clock rate based on the bandwidth requirements >>> registered by >>> memory clients through the PM_QOS_MEMORY_BANDWIDTH class. >>> >>> Note: this is just an example and not a proper driver for a external >>> memory >>> controller. Its only purpose is to illustrate how such a driver would >>> set the >>> frequency of the external memory clock based on the bandwidth >>> requirements of >>> memory clients. >> >>> diff --git a/arch/arm/mach-tegra/tegra.c b/arch/arm/mach-tegra/tegra.c >> >>> @@ -112,6 +117,11 @@ static void __init tegra_dt_init(void) >>> parent = soc_device_to_device(soc_dev); >>> >>> /* >>> + * HACK: register a platform device to probe the driver >>> + */ >>> + platform_device_register(&tegra_emc); >> >> I don't think this is a hack, except for the bug: That should only >> happen on Tegra124 not on all Tegra SoCs. >> >> Do you intend all 3 patches in this series to be merged? You'd mentioned >> you didn't when asked about this for a previous version. I'm not sure if >> that's changed? > > Yeah, I don't want 3/3 merged because we don't have a functional EMC > clock yet on T124, and because I don't know yet where will be the best > place to have that code in. That depends on Mikko's work on the real EMC > driver which is in a bit of flux right now. > > I have kept posting it just because I think it complements nicely the > explanation in the cover letter, but maybe confuses more than helps. OK. If you make this one a [PATCH RFC], or add a note to that effect to the commit description (perhaps underneath the --- line), that'd be helpful for future postings. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/mach-tegra/tegra.c b/arch/arm/mach-tegra/tegra.c index 5ef5173..099d8e7f 100644 --- a/arch/arm/mach-tegra/tegra.c +++ b/arch/arm/mach-tegra/tegra.c @@ -70,6 +70,11 @@ u32 tegra_uart_config[3] = { 0, }; +static struct platform_device tegra_emc = { + .name = "tegra124-emc", + .id = -1, +}; + static void __init tegra_init_early(void) { of_register_trusted_foundations(); @@ -112,6 +117,11 @@ static void __init tegra_dt_init(void) parent = soc_device_to_device(soc_dev); /* + * HACK: register a platform device to probe the driver + */ + platform_device_register(&tegra_emc); + + /* * Finished with the static registrations now; fill in the missing * devices */ diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig index fab81a1..2088b2b 100644 --- a/drivers/memory/Kconfig +++ b/drivers/memory/Kconfig @@ -61,6 +61,15 @@ config TEGRA30_MC analysis, especially for IOMMU/SMMU(System Memory Management Unit) module. +config TEGRA124_EMC + tristate "Tegra124 External Memory Controller (EMC) driver" + default y + depends on ARCH_TEGRA_124_SOC + help + This driver is for the External Memory Controller (EMC) module + available in Tegra124 SoCs. + + config FSL_CORENET_CF tristate "Freescale CoreNet Error Reporting" depends on FSL_SOC_BOOKE diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile index 4055c47..0a6d117 100644 --- a/drivers/memory/Makefile +++ b/drivers/memory/Makefile @@ -12,3 +12,4 @@ obj-$(CONFIG_FSL_IFC) += fsl_ifc.o obj-$(CONFIG_MVEBU_DEVBUS) += mvebu-devbus.o obj-$(CONFIG_TEGRA20_MC) += tegra20-mc.o obj-$(CONFIG_TEGRA30_MC) += tegra30-mc.o +obj-$(CONFIG_TEGRA124_EMC) += tegra124-emc.o diff --git a/drivers/memory/tegra124-emc.c b/drivers/memory/tegra124-emc.c new file mode 100644 index 0000000..a290ad5 --- /dev/null +++ b/drivers/memory/tegra124-emc.c @@ -0,0 +1,117 @@ +/* + * Copyright (c) 2013, NVIDIA CORPORATION. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/clk.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pm_qos.h> + +#define DRV_NAME "tegra124-emc" +#define EMC_FREQ_CUTOFF_USE_130_PERCENT 100000000 +#define EMC_FREQ_CUTOFF_USE_140_PERCENT 50000000 +#define BYTES_PER_EMC_CLOCK 16 + +struct tegra124_emc { + struct clk *clk; + struct notifier_block memory_bw_notifier; +}; + +static struct platform_device *emc_pdev; + +static unsigned long tegra124_emc_bw_to_freq_req(s32 bw) +{ + return (bw * 8 + BYTES_PER_EMC_CLOCK - 1) / BYTES_PER_EMC_CLOCK; +} + +static void tegra124_emc_update_rate(struct tegra124_emc *emc, s32 total_bandwidth) +{ + struct clk *emc_master; + unsigned long freq; + + emc_master = clk_get_parent(emc->clk); + freq = tegra124_emc_bw_to_freq_req(total_bandwidth * 1024); + freq = clk_round_rate(emc_master, freq); + + /* Depending on frequency value, the amount of bandwidth usage % of + * total we should use is different. Thus we should request a multiple of + * original bandwidth on this. Use 1.4 for < 50MHz, 1.3 for < 100MHz, + * else 1.1 */ + if (freq < EMC_FREQ_CUTOFF_USE_140_PERCENT) + total_bandwidth += 4 * total_bandwidth / 10; /* 1.4 */ + else if (freq < EMC_FREQ_CUTOFF_USE_130_PERCENT) + total_bandwidth += 3 * total_bandwidth / 10; /* 1.3 */ + else + total_bandwidth += total_bandwidth / 10; /* 1.1 */ + + freq = tegra124_emc_bw_to_freq_req(total_bandwidth * 1024); + + clk_set_floor_rate(emc->clk, freq); +} + +int memory_bw_notify(struct notifier_block *nb, unsigned long data, void *dummy) +{ + s32 total_bw = (s32) data; + struct tegra124_emc *emc = + container_of(nb, struct tegra124_emc, + memory_bw_notifier); + + tegra124_emc_update_rate(emc, total_bw); + + return NOTIFY_OK; +} + +static int tegra124_emc_probe(struct platform_device *pdev) +{ + struct tegra124_emc *emc; + + emc_pdev = pdev; + + emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL); + if (emc == NULL) { + dev_err(&pdev->dev, "Failed to allocate private memory\n"); + return -ENOMEM; + } + + emc->clk = clk_get_sys("tegra-clk-debug", "emc"); + if (IS_ERR(emc->clk)) { + devm_kfree(&pdev->dev, emc); + dev_err(&pdev->dev, "Can not find EMC clock\n"); + return -EPROBE_DEFER; + } + + platform_set_drvdata(emc_pdev, emc); + + emc->memory_bw_notifier.notifier_call = memory_bw_notify; + pm_qos_add_notifier(PM_QOS_MEMORY_BANDWIDTH, &emc->memory_bw_notifier); + + return 0; +} + +static struct platform_driver tegra124_emc_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, + .probe = tegra124_emc_probe, +}; + +module_platform_driver(tegra124_emc_driver); + +MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>"); +MODULE_DESCRIPTION("Tegra124 EMC driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" DRV_NAME);
Sets the EMC clock rate based on the bandwidth requirements registered by memory clients through the PM_QOS_MEMORY_BANDWIDTH class. Note: this is just an example and not a proper driver for a external memory controller. Its only purpose is to illustrate how such a driver would set the frequency of the external memory clock based on the bandwidth requirements of memory clients. --- v4: * Add hack so the driver gets actually registered. * Use the tegra-clk-debug dev_id to query the EMC clock * Get units right and use types consistently --- arch/arm/mach-tegra/tegra.c | 10 ++++ drivers/memory/Kconfig | 9 ++++ drivers/memory/Makefile | 1 + drivers/memory/tegra124-emc.c | 117 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 137 insertions(+) create mode 100644 drivers/memory/tegra124-emc.c