Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752564AbdHIUKq (ORCPT ); Wed, 9 Aug 2017 16:10:46 -0400 Received: from mail-pf0-f172.google.com ([209.85.192.172]:34669 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751932AbdHIUKk (ORCPT ); Wed, 9 Aug 2017 16:10:40 -0400 From: Bjorn Andersson To: Andy Gross , David Brown , Rob Herring , Mark Rutland Cc: Stephen Boyd , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org Subject: [PATCH v3 2/3] firmware: qcom: scm: Expose download-mode control Date: Wed, 9 Aug 2017 13:10:32 -0700 Message-Id: <20170809201033.4967-3-bjorn.andersson@linaro.org> X-Mailer: git-send-email 2.12.0 In-Reply-To: <20170809201033.4967-1-bjorn.andersson@linaro.org> References: <20170809201033.4967-1-bjorn.andersson@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8368 Lines: 256 In order to aid post-mortem debugging the Qualcomm platforms provides a "memory download mode", where the boot loader will provide an interface for custom tools to "download" the content of RAM to a host machine. The mode is triggered by writing a magic value somehwere in RAM, that is read in the boot code path after a warm-restart. Two mechanism for setting this magic value are supported in modern platforms; a direct SCM call to enable the mode or through a secure io write of a magic value. In order for a normal reboot not to trigger "download mode" the magic must be cleared during a clean reboot. Download mode has to be enabled by including qcom_scm.download_mode=1 on the command line. Signed-off-by: Bjorn Andersson --- Changes since v2: - Define memory address by reference to TCSR - Provide Kconfig option for defaulting to enabled - Provided some comment in the code Changes since v1: - Specify DT propert being two-cell - Correct handling of scm-call return code .../devicetree/bindings/firmware/qcom,scm.txt | 2 + drivers/firmware/Kconfig | 11 ++++ drivers/firmware/qcom_scm-32.c | 6 ++ drivers/firmware/qcom_scm-64.c | 13 ++++ drivers/firmware/qcom_scm.c | 69 ++++++++++++++++++++++ drivers/firmware/qcom_scm.h | 2 + 6 files changed, 103 insertions(+) diff --git a/Documentation/devicetree/bindings/firmware/qcom,scm.txt b/Documentation/devicetree/bindings/firmware/qcom,scm.txt index 20f26fbce875..838dba841797 100644 --- a/Documentation/devicetree/bindings/firmware/qcom,scm.txt +++ b/Documentation/devicetree/bindings/firmware/qcom,scm.txt @@ -18,6 +18,8 @@ Required properties: * Core, iface, and bus clocks required for "qcom,scm" - clock-names: Must contain "core" for the core clock, "iface" for the interface clock and "bus" for the bus clock per the requirements of the compatible. +- qcom,dload-mode: phandle reference to the TCSR hardware block containing the + download mode control register (optional) Example for MSM8916: diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 6e4ed5a9c6fd..ed23c77d6361 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -215,6 +215,17 @@ config QCOM_SCM_64 def_bool y depends on QCOM_SCM && ARM64 +config QCOM_SCM_DOWNLOAD_MODE_DEFAULT + bool "Qualcomm Download mode enabled by default" + depends on QCOM_SCM + help + A device with "download mode" enabled will upon an unexpected + warm-restart enter a special debug mode that allows the user to + "download" memory content over USB for offline postmortem analysis. + The feature can be enabled/disabled on the kernel command line. + + Say Y here to enable "download mode" by default. + config TI_SCI_PROTOCOL tristate "TI System Control Interface (TISCI) Message Protocol" depends on TI_MESSAGE_MANAGER diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c index 11fdb1584823..68b2033bc30e 100644 --- a/drivers/firmware/qcom_scm-32.c +++ b/drivers/firmware/qcom_scm-32.c @@ -561,6 +561,12 @@ int __qcom_scm_pas_mss_reset(struct device *dev, bool reset) return ret ? : le32_to_cpu(out); } +int __qcom_scm_set_dload_mode(struct device *dev, bool enable) +{ + return qcom_scm_call_atomic2(QCOM_SCM_SVC_BOOT, QCOM_SCM_SET_DLOAD_MODE, + enable ? QCOM_SCM_SET_DLOAD_MODE : 0, 0); +} + int __qcom_scm_set_remote_state(struct device *dev, u32 state, u32 id) { struct { diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c index bf50fb59852e..3fea6f563ca9 100644 --- a/drivers/firmware/qcom_scm-64.c +++ b/drivers/firmware/qcom_scm-64.c @@ -440,6 +440,19 @@ int __qcom_scm_iommu_secure_ptbl_init(struct device *dev, u64 addr, u32 size, return ret; } +int __qcom_scm_set_dload_mode(struct device *dev, bool enable) +{ + struct qcom_scm_desc desc = {0}; + struct arm_smccc_res res; + + desc.args[0] = QCOM_SCM_SET_DLOAD_MODE; + desc.args[1] = enable ? QCOM_SCM_SET_DLOAD_MODE : 0; + desc.arginfo = QCOM_SCM_ARGS(2); + + return qcom_scm_call(dev, QCOM_SCM_SVC_BOOT, QCOM_SCM_SET_DLOAD_MODE, + &desc, &res); +} + int __qcom_scm_io_readl(struct device *dev, phys_addr_t addr, unsigned int *val) { diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c index e18d63935648..88472cde8936 100644 --- a/drivers/firmware/qcom_scm.c +++ b/drivers/firmware/qcom_scm.c @@ -19,15 +19,20 @@ #include #include #include +#include #include #include #include +#include #include #include #include #include "qcom_scm.h" +static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT); +module_param(download_mode, bool, 0); + #define SCM_HAS_CORE_CLK BIT(0) #define SCM_HAS_IFACE_CLK BIT(1) #define SCM_HAS_BUS_CLK BIT(2) @@ -38,6 +43,8 @@ struct qcom_scm { struct clk *iface_clk; struct clk *bus_clk; struct reset_controller_dev reset; + + u64 dload_mode_addr; }; static struct qcom_scm *__scm; @@ -345,6 +352,48 @@ int qcom_scm_io_writel(phys_addr_t addr, unsigned int val) } EXPORT_SYMBOL(qcom_scm_io_writel); +static void qcom_scm_set_download_mode(bool enable) +{ + bool avail; + int ret = 0; + + avail = __qcom_scm_is_call_available(__scm->dev, + QCOM_SCM_SVC_BOOT, + QCOM_SCM_SET_DLOAD_MODE); + if (avail) { + ret = __qcom_scm_set_dload_mode(__scm->dev, enable); + } else if (__scm->dload_mode_addr) { + ret = __qcom_scm_io_writel(__scm->dev, __scm->dload_mode_addr, + enable ? QCOM_SCM_SET_DLOAD_MODE : 0); + } else { + dev_err(__scm->dev, + "No available mechanism for setting download mode\n"); + } + + if (ret) + dev_err(__scm->dev, "failed to set download mode: %d\n", ret); +} + +static int qcom_scm_find_dload_address(struct device *dev, u64 *addr) +{ + struct device_node *tcsr; + struct resource res; + int ret; + + tcsr = of_parse_phandle(dev->of_node, "qcom,dload-mode", 0); + if (!tcsr) + return 0; + + ret = of_address_to_resource(tcsr, 0, &res); + of_node_put(tcsr); + if (ret) + return ret; + + *addr = res.start; + + return 0; +} + /** * qcom_scm_is_available() - Checks if SCM is available */ @@ -370,6 +419,10 @@ static int qcom_scm_probe(struct platform_device *pdev) if (!scm) return -ENOMEM; + ret = qcom_scm_find_dload_address(&pdev->dev, &scm->dload_mode_addr); + if (ret < 0) + return ret; + clks = (unsigned long)of_device_get_match_data(&pdev->dev); if (clks & SCM_HAS_CORE_CLK) { scm->core_clk = devm_clk_get(&pdev->dev, "core"); @@ -418,9 +471,24 @@ static int qcom_scm_probe(struct platform_device *pdev) __qcom_scm_init(); + /* + * If requested enable "download mode", from this point on warmboot + * will cause the the boot stages to enter download mode, unless + * disabled below by a clean shutdown/reboot. + */ + if (download_mode) + qcom_scm_set_download_mode(true); + return 0; } +static void qcom_scm_shutdown(struct platform_device *pdev) +{ + /* Clean shutdown, disable download mode to allow normal restart */ + if (download_mode) + qcom_scm_set_download_mode(false); +} + static const struct of_device_id qcom_scm_dt_match[] = { { .compatible = "qcom,scm-apq8064", /* FIXME: This should have .data = (void *) SCM_HAS_CORE_CLK */ @@ -448,6 +516,7 @@ static struct platform_driver qcom_scm_driver = { .of_match_table = qcom_scm_dt_match, }, .probe = qcom_scm_probe, + .shutdown = qcom_scm_shutdown, }; static int __init qcom_scm_init(void) diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h index a60e4b9b1394..83f171c23943 100644 --- a/drivers/firmware/qcom_scm.h +++ b/drivers/firmware/qcom_scm.h @@ -14,9 +14,11 @@ #define QCOM_SCM_SVC_BOOT 0x1 #define QCOM_SCM_BOOT_ADDR 0x1 +#define QCOM_SCM_SET_DLOAD_MODE 0x10 #define QCOM_SCM_BOOT_ADDR_MC 0x11 #define QCOM_SCM_SET_REMOTE_STATE 0xa extern int __qcom_scm_set_remote_state(struct device *dev, u32 state, u32 id); +extern int __qcom_scm_set_dload_mode(struct device *dev, bool enable); #define QCOM_SCM_FLAG_HLOS 0x01 #define QCOM_SCM_FLAG_COLDBOOT_MC 0x02 -- 2.12.0