From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sowjanya Komatineni Subject: [PATCH V1 02/11] mmc: sdhci: allow host to specify maximum tuning loops Date: Fri, 1 Mar 2019 21:20:16 -0800 Message-ID: <1551504025-3541-2-git-send-email-skomatineni@nvidia.com> References: <1551504025-3541-1-git-send-email-skomatineni@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <1551504025-3541-1-git-send-email-skomatineni@nvidia.com> Sender: linux-kernel-owner@vger.kernel.org To: adrian.hunter@intel.com, ulf.hansson@linaro.org, robh+dt@kernel.org, mark.rutland@arm.com, riteshh@codeaurora.org Cc: thierry.reding@gmail.com, jonathanh@nvidia.com, anrao@nvidia.com, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, Sowjanya Komatineni List-Id: devicetree@vger.kernel.org As per the Host Controller Standard Specification Version 4.20, limitation of tuning iteration count is removed as PLL locking time can be longer than UHS-1 tuning due to larger PVT fluctuation and it will result in increase of tuning iteration to complete the tuning. This patch creates a hook get_max_tuning_loop_count to allow hosts to specify maximum tuning iterations and updates execute_tuning to use the specified maximum tuning iteration count. Signed-off-by: Sowjanya Komatineni --- drivers/mmc/host/sdhci.c | 7 +++++-- drivers/mmc/host/sdhci.h | 1 + 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index a8141ff9be03..e9e919218006 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2366,12 +2366,15 @@ EXPORT_SYMBOL_GPL(sdhci_send_tuning); static int __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode) { int i; + int tuning_loop_count = MAX_TUNING_LOOP; + if (host->ops->get_max_tuning_loop_count) + tuning_loop_count = host->ops->get_max_tuning_loop_count(host); /* * Issue opcode repeatedly till Execute Tuning is set to 0 or the number - * of loops reaches 40 times. + * of loops reaches tuning loop count. */ - for (i = 0; i < MAX_TUNING_LOOP; i++) { + for (i = 0; i < tuning_loop_count; i++) { u16 ctrl; sdhci_send_tuning(host, opcode); diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 01002cba1359..c80e0d6f9b10 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h @@ -638,6 +638,7 @@ struct sdhci_ops { unsigned int (*get_ro)(struct sdhci_host *host); void (*reset)(struct sdhci_host *host, u8 mask); int (*platform_execute_tuning)(struct sdhci_host *host, u32 opcode); + int (*get_max_tuning_loop_count)(struct sdhci_host *host); void (*set_uhs_signaling)(struct sdhci_host *host, unsigned int uhs); void (*hw_reset)(struct sdhci_host *host); void (*adma_workaround)(struct sdhci_host *host, u32 intmask); -- 2.7.4