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mmc: atmel-mci: add support for odd clock dividers 

Add an odd clock divider capability available from v5xx. It also involves
changing the clock divider calculation, and changing the switch-case
statement to use top-down fallthrough.

Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Ludovic Desroches 2012-03-21 16:41:23 +01:00 committed by Chris Ball
parent 33ab4bbbdf
commit faf8180b20
2 changed files with 30 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
drivers/mmc/host/atmel-mci-regs.h
View File

@ -31,6 +31,7 @@
# define ATMCI_MR_PDCFBYTE ( 1 << 13) /* Force Byte Transfer */
# define ATMCI_MR_PDCPADV ( 1 << 14) /* Padding Value */
# define ATMCI_MR_PDCMODE ( 1 << 15) /* PDC-oriented Mode */
# define ATMCI_MR_CLKODD(x) ((x) << 16) /* LSB of Clock Divider */
#define ATMCI_DTOR 0x0008 /* Data Timeout */
# define ATMCI_DTOCYC(x) ((x) << 0) /* Data Timeout Cycles */
# define ATMCI_DTOMUL(x) ((x) << 4) /* Data Timeout Multiplier */

48
drivers/mmc/host/atmel-mci.c
View File

@ -77,6 +77,7 @@ struct atmel_mci_caps {
bool has_cstor_reg;
bool has_highspeed;
bool has_rwproof;
bool has_odd_clk_div;
};
struct atmel_mci_dma {
@ -1134,16 +1135,27 @@ static void atmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
}
/* Calculate clock divider */
clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
if (clkdiv > 255) {
dev_warn(&mmc->class_dev,
"clock %u too slow; using %lu\n",
clock_min, host->bus_hz / (2 * 256));
clkdiv = 255;
if (host->caps.has_odd_clk_div) {
clkdiv = DIV_ROUND_UP(host->bus_hz, clock_min) - 2;
if (clkdiv > 511) {
dev_warn(&mmc->class_dev,
"clock %u too slow; using %lu\n",
clock_min, host->bus_hz / (511 + 2));
clkdiv = 511;
}
host->mode_reg = ATMCI_MR_CLKDIV(clkdiv >> 1)
| ATMCI_MR_CLKODD(clkdiv & 1);
} else {
clkdiv = DIV_ROUND_UP(host->bus_hz, 2 * clock_min) - 1;
if (clkdiv > 255) {
dev_warn(&mmc->class_dev,
"clock %u too slow; using %lu\n",
clock_min, host->bus_hz / (2 * 256));
clkdiv = 255;
}
host->mode_reg = ATMCI_MR_CLKDIV(clkdiv);
}
host->mode_reg = ATMCI_MR_CLKDIV(clkdiv);
/*
* WRPROOF and RDPROOF prevent overruns/underruns by
* stopping the clock when the FIFO is full/empty.
@ -2014,37 +2026,35 @@ static void __init atmci_get_cap(struct atmel_mci *host)
"version: 0x%x\n", version);
host->caps.has_dma = 0;
host->caps.has_pdc = 0;
host->caps.has_pdc = 1;
host->caps.has_cfg_reg = 0;
host->caps.has_cstor_reg = 0;
host->caps.has_highspeed = 0;
host->caps.has_rwproof = 0;
host->caps.has_odd_clk_div = 0;
/* keep only major version number */
switch (version & 0xf00) {
case 0x100:
host->caps.has_pdc = 1;
break;
case 0x200:
host->caps.has_pdc = 1;
host->caps.has_rwproof = 1;
break;
case 0x300:
case 0x400:
case 0x500:
host->caps.has_odd_clk_div = 1;
case 0x400:
case 0x300:
#ifdef CONFIG_AT_HDMAC
host->caps.has_dma = 1;
#else
host->caps.has_dma = 0;
dev_info(&host->pdev->dev,
"has dma capability but dma engine is not selected, then use pio\n");
#endif
host->caps.has_pdc = 0;
host->caps.has_cfg_reg = 1;
host->caps.has_cstor_reg = 1;
host->caps.has_highspeed = 1;
case 0x200:
host->caps.has_rwproof = 1;
case 0x100:
break;
default:
host->caps.has_pdc = 0;
dev_warn(&host->pdev->dev,
"Unmanaged mci version, set minimum capabilities\n");
break;