From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH 2/3] mmc: sdhci-esdhc-imx: add SD clock limitation for imx6ull Date: Thu, 27 Dec 2018 10:01:24 +0200 Message-ID: References: <1545292612-14471-1-git-send-email-haibo.chen@nxp.com> <1545292612-14471-2-git-send-email-haibo.chen@nxp.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1545292612-14471-2-git-send-email-haibo.chen@nxp.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: BOUGH CHEN , "ulf.hansson@linaro.org" , "robh+dt@kernel.org" , "mark.rutland@arm.com" , "shawnguo@kernel.org" , "s.hauer@pengutronix.de" , "kernel@pengutronix.de" , Fabio Estevam Cc: "devicetree@vger.kernel.org" , "linux-mmc@vger.kernel.org" , dl-linux-imx , "linux-arm-kernel@lists.infradead.org" List-Id: linux-mmc@vger.kernel.org On 20/12/18 9:49 AM, BOUGH CHEN wrote: > i.MX6ULL has errata ERR010450, point out that due to SOC I/O > timing limitation, for eMMC HS200 and SD/SDIO 3.0 SDR104, the > clock rate can't exceed 150MHz. And for eMMC DDR52 and SD/SDIO > DDR50 mode, the clock rate can't exceed 45MHz. > > This patch add this limit for imx6ull. > > Signed-off-by: Haibo Chen Apart from the kbuild test robot complaints (do they need to be fixed?): Acked-by: Adrian Hunter > --- > drivers/mmc/host/sdhci-esdhc-imx.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c > index d0d3193..75a2484 100644 > --- a/drivers/mmc/host/sdhci-esdhc-imx.c > +++ b/drivers/mmc/host/sdhci-esdhc-imx.c > @@ -138,7 +138,11 @@ > #define ESDHC_FLAG_HS200 BIT(8) > /* The IP supports HS400 mode */ > #define ESDHC_FLAG_HS400 BIT(9) > - > +/* The IP has errata ERR010450 > + * uSDHC: Due to the I/O timing limit, for SDR mode, SD card clock can't > + * exceed 150MHz, for DDR mode, SD card clock can't exceed 45MHz. > + */ > +#define ESDHC_FLAG_ERR010450 BIT(10) > /* A clock frequency higher than this rate requires strobe dll control */ > #define ESDHC_STROBE_DLL_CLK_FREQ 100000000 > > @@ -177,6 +181,12 @@ struct esdhc_soc_data { > | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200, > }; > > +static struct esdhc_soc_data usdhc_imx6ull_data = { > + .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING > + | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200 > + | ESDHC_FLAG_ERR010450, > +}; > + > static struct esdhc_soc_data usdhc_imx7d_data = { > .flags = ESDHC_FLAG_USDHC | ESDHC_FLAG_STD_TUNING > | ESDHC_FLAG_HAVE_CAP1 | ESDHC_FLAG_HS200 > @@ -227,6 +237,7 @@ struct pltfm_imx_data { > { .compatible = "fsl,imx6sx-usdhc", .data = &usdhc_imx6sx_data, }, > { .compatible = "fsl,imx6sl-usdhc", .data = &usdhc_imx6sl_data, }, > { .compatible = "fsl,imx6q-usdhc", .data = &usdhc_imx6q_data, }, > + { .compatible = "fsl,imx6ull-usdhc", .data = &usdhc_imx6ull_data, }, > { .compatible = "fsl,imx7d-usdhc", .data = &usdhc_imx7d_data, }, > { /* sentinel */ } > }; > @@ -733,6 +744,12 @@ static inline void esdhc_pltfm_set_clock(struct sdhci_host *host, > | ESDHC_CLOCK_MASK); > sdhci_writel(host, temp, ESDHC_SYSTEM_CONTROL); > > + if (imx_data->socdata->flags & ESDHC_FLAG_ERR010450) { > + if (imx_data->is_ddr) > + clock = clock > 45000000 ? 45000000 : clock; > + else > + clock = clock > 150000000 ? 150000000 : clock; > + > while (host_clock / (16 * pre_div * ddr_pre_div) > clock && > pre_div < 256) > pre_div *= 2; >